Cooling System Rebuild. PICS!
 

Cooling System Overhaul
1996 318ti Auto / M44.

Parts List

• Radiator, 17111728905 - $128 (ebay - AC Imports)
• OE Water Pump, 11510393338? - $79.82 (Tischer BMW)
• 1 Gallon Coolant, 82141467704 - $18.48 (Local Dealer)

Autohausaz.com Parts

• Thermostat w/housing, 11531743017 - $34.30
• Radiator Cap, 17111742231 - $9.78
• Upper Radiator Hose, 11531743535 - $13.70
• Lower Radiator Hose, 11531247261 - $8.63
• Combo Vacuum/Coolant Hose, 11151247903 - $15.35
• Small Reservoir Hose, 11531743295 - $13.61
• Misc. Hose #1, 11531247398 - $8.17
• Misc. Hose #2, 64211387010 - $5.94
• Heater Hose #1, 64218391252 (or 64211394295 on 4/96+ cars*) - $5.50
• Heater Hose #2, 64211394291 - $6.23
• Plastic Coolant Connector #1 (Block), 11531714738 - $11.54
• O-Ring for Block Coolant Connector, 11531709157 - $1.15
• Plastic Coolant Connector #2 (Head), 11531743679 - $8.18
• Lower Intake Manifold Gasket, 11611734684 - $3.50
• Upper to Lower Manifold Gasket (2x), 11611247478 - $2.92 total
• Block Coolant Drain Seal Ring, 07119963200 - $0.12

*My car was a 3/1996 build, but it used the newer 4/1996+ hoses.

Parts Total, with shipping and tax: $374.92 .

Quick Links to RealOEM.com Diagrams

Plastic Coolant Connector #1 (Block)

Plastic Coolant Connector #2 (Head)

Water Pump / Thermostat

Main Radiator Hoses

Intake Manifold Gaskets

Radiator

Heater Hoses

And some new part pictures. Hoses, connectors, and gaskets.
http://i44.photobucket.com/albums/f2...ling/hoses.jpg

eBay (Behr?) Radiator.
http://i44.photobucket.com/albums/f2...g/radiator.jpg

Close ups of block coolant connector.
http://i44.photobucket.com/albums/f2.../coolant2a.jpg
http://i44.photobucket.com/albums/f2.../coolant2b.jpg

Close ups of head coolant connector.
http://i44.photobucket.com/albums/f2...onnector1a.jpg
http://i44.photobucket.com/albums/f2...onnector1b.jpg

The entire project is very involved, so a step-by-step guide is about impossible. I’ll try my best though!

Many parts need to be removed to have clear access to the radiator, water pump, and coolant connectors. Start by safely supporting your vehicle on jack stands of ramps. Disconnect the negative battery terminal.

In this picture I have removed the entire intake box, rubber intake boot, electric cooling fan and main intake tubing.
http://i44.photobucket.com/albums/f2...ling/work1.jpg

Other angles of the exposed radiator.
http://i44.photobucket.com/albums/f2...ling/work2.jpg
http://i44.photobucket.com/albums/f2...ling/work3.jpg

Next I removed the AC belt, and main serpentine belt to gain access to the water pump and pulley. The four main pully bolts were simple to remove, as long as the belt was still attached.
http://i44.photobucket.com/albums/f2...ling/pump1.jpg

Here’s a pic of the old pump, after the pulley was removed.
http://i44.photobucket.com/albums/f2...ling/pump2.jpg

Unfortunately I tapped the pully with a rubber mallet and it broke the pulley. I was not expecting the pulley to be plastic. Be careful! I eventually just pulled the pulley off by hand.
http://i44.photobucket.com/albums/f2...ling/pump3.jpg

Time to start into the intake manifold. Both the upper and lower sections need to be removed to access the coolant connectors as well as some of the coolant hoses.

Numerous electrical connections and vacuum hoses need to be removed for the upper manifold to come off. The throttle cable also need to be disconnected. There are 2 nuts and 1 long bolt holding the upper intake manifold on. Along with these are two other supports that need to be loosened, but not removed. Here's a picture of the upper mainfold pulled.
http://i44.photobucket.com/albums/f2...ling/work4.jpg

Thanks, that is a nice write up. I wish I photographed mine. I just did much of the same thing on my 1995 M42 while changing the starter. The sensors are a royal pain in the butt to unhook/and re-hook. Be sure to label some of them well, although it is somewhat clear where each one goes (use tape because permanent marker rubs off if you have grease on your fingers). I think it took me 15 hours to remove/reinstall the air intakes, all new hoses and misc, and the starter.

You don't have to take this off until you remove the lower manifold. The entire flange with coolant hoses attached (remove the breather hose from the PCV valve) will slide between the intake runners by the sensor "squid". The reason I call it a squid will become apparent when you have it taken off. I think the M44 has a better design for the squid that will let you disconnect it from the main wiring harness. For the flange, on mine, one hose from the flange attaches to the tubular plastic piece on the side of the block, and the other hose attaches to the head somewhere below the intake, if memory serves.

I think there was 9 or 10 sensors and the starter and alternator wires attached to the squid, including the reverse light switch, which had me fooled. I couldn't find what was holding the squid in place. I think all the connectors are: 2 ping sensors low in the block, 2 sensors just under the intake, 2 running from a harness around the front of the engine, 1 going by the alternator, 1 going to a vacuum valve by the charcoal canister, 1 to the reverse light switch, and 1 to the ICV. Then the alternator has a positive cables and a control signal wire, and the starter has two large positive cables, and two small control signal cables connected to it (grounds comes from the engine block). I think those are all the wires on the squid that I recall.

Also the two fuel lines going to the fuel rails make it a pain to remove the lower intake manifold as it hangs up when you try to pull it over them. You might remove the rubber hoses from them to make it easier. Also, remove the fuel injectors carefully so you don't chip them. You don't need to remove the clips from them if you don't want, they all pop in as a unit attached to the fuel rail (unbolt the fuel rail and pull all 4 off at once).

Finally, it makes it easier to connect/disconnect wires from the squid if you remove all the bolts holding the lower intake in place so you can lift it a few inches to gain more clearance. There are 5 or so bolts on the head side, mostly easily accessible, and two large bolts holding it to a bracket above the alternator. If you can't disconnect the squid from the main harness, you will likely have to remove the vent piece for the cabin air filters (see the knowledge base articles) to release the main engine wiring harness, and disconnect all the connectors by the fuse box and pull the harness out across the engine to the battery side of the car so it is out of the way. Those circular connectors have neat little clips that hold them to the body by the fuse box. Very easy to remove. If you do need to remove the harness (i.e. your squid doesn't detach from the main harness), I attached a drawing.

I should point out again, that I have the M42, and it appears your vehicle is slightly different under the intake, the squid might be much easier to remove in yours. I see your Idle Control valve (attaches to the air lines going to the fuel injectors) is in a different location towards the front of the engine. Mine was attached directly to the top of the squid, and I just see the air hose for yours going off to the side where you have it disconnected.

The injector rail needs to come off before you remove the lower intake manifold. The electrical connections need to be disconnected, as well as the fuel lines. Depressurize your fuel system with a cold engine. Depress the thing(?) on the schraeder valve that's welded to the fuel rail. Have a rag ready to soak up fuel. Gently wiggle loose the entire fuel rail/injector/air hose assembly.
http://i44.photobucket.com/albums/f2...ling/work5.jpg

With the fuel rail out of the way, the tangled mess of a electrical harness needs to be disconnected and removed. Unfortunately the wires run through the center of the lower intake manifold. The most of the connections are simple plugs, but you'll also need to remove three nuts & wires leading to the starter. There are also two nuts and wires leading to the alternator. They need to be removed as well. The starter wires are an absolute pain!

http://i44.photobucket.com/albums/f2...ling/work6.jpg

My-oh-my!! Look at my fuel injectors. :eek: I cleaned them up as gently as possible after this shot. Hopefully I didn't plug anything up....

http://i44.photobucket.com/albums/f2...ling/work7.jpg

Here's a shot after I have disconnected the wiring harness and folded it away (towards the USA driver's side)

http://i44.photobucket.com/albums/f2...ling/work8.jpg

I removed the intake manifold flange (with holds the PVC valve) by disconnecting the two coolant lines and the one vacuum line. The lower intake manifold was free to remove at this point. Only minimal wiggling is required to make it past the two fuel lines. The lower intake manifold and intake ports were absolutely CAKED with crud/carbon/whatever. I spent quite a while degunking the manifold, and spent a little time carefully cleaning the intake ports.

http://i44.photobucket.com/albums/f2...ling/work9.jpg

All that prep, and finally we can start working on the cooling system itself. That's what I tore this thing apart for, right?? Here's the coolant connector that's attached to the side of the engine block.

http://i44.photobucket.com/albums/f2...ing/work10.jpg

I removed the two bolts and three coolant hoses that are connected to it, then gently pulled it away from the block. SNAP! I think it was in a weakend state, because it gave way with very little effort. Here's a little carnage. It left the O-ring and some plastic in the block.

http://i44.photobucket.com/albums/f2...ing/work12.jpg

http://i44.photobucket.com/albums/f2...ing/work13.jpg

Time for the back of the head connector. Hard to take any pictures of it becuase it's so tight back there. This is a shot after the new one was in. Wow is this thing a b!tch. You need an open ended wrench for the top bolt, and a socket/rachet for the lower bolt. Sorry, I forgot the size. Getting the hose clamps off is really hard as well. That required a tiny 6 mm open ended wrench. Removing the cabin filter cover is pretty much required for this. It gave me a little more working room. My connector was still very study. I smacked it against the concrete a few times and jumped on it once. It didn't break.

http://i44.photobucket.com/albums/f2...ing/work11.jpg

Radiator and water pump time. Removing the radiator is pretty simple. Shove a small flathead screwdriver into the main clips (look for the arrow), then pull straight up on the clip. If you have an automatic like me, the trans cooler needs to be unscrewed from the main radiator. The are 4 sheet metal screws connecting them, and thankfully the trans line DO NOT need to be opened. Here's a shot of my tans cooler!! This one is sandwiched between the AC and main radiator, so I don't understand how it got so caked with junk. The AC condenser (?) in front wasn't very dirty at all.? Nice to know I've been running without a trans cooler for quite a long time.

http://i44.photobucket.com/albums/f2...ing/work14.jpg

With the radiator out of the way, you now have pretty good access to work on the water pump. This is another tough one. I ended up breaking the old pump using the threaded holes to pull/press it out. It came out by gently prying it out with a hammer claw. I was pleased that the water pump bore was very clean and pretty much corrosion free.

http://i44.photobucket.com/albums/f2...ing/work15.jpg

Old vs. New. I believe the old one was a Thyssen. The new one was straight from a dealer with BMW logo and all. They definitely were not the same part. Both had a plastic impeller.

http://i44.photobucket.com/albums/f2...ing/work16.jpg

I lighly greased the water pump o-ring before installation. The pump requires quite a bit of effort to press in. The o-ring is quite meaty and gets compressed a fair amount.

http://i44.photobucket.com/albums/f2...ing/work17.jpg

Now's a good time to replace your thermostat. I didn't because mine was replaced just a year ago after it failed (stuck open). Here's the trans cooler attached to the new radiator. I cleaning as good as I could without backflushing it with a hose. That would have been ideal, but the work was done in a garage. Some carb cleaner and a brush did a fair job.

http://i44.photobucket.com/albums/f2...ing/work18.jpg

And she sleeps. Kiboshed for the evening due to an incorrect hose. From the realoem.com and bmwfans.info diagrams, there was a coolant hose switch in 4/1996. My car is a 3/1996, so I ordered the older version. Turns out I have the newer version. I went this far, and dug this deep, I figured I ought to get the correct hose and do the job correctly the first time. Hopefully a dealer will have it in stock tomorrow morning.....

http://i44.photobucket.com/albums/f2...ing/work19.jpg

Day 3. Thankfully a local dealer had the heater hose in stock so I as able to finish the project today. I didn't take any pictures as everything is just in reverse. Just make triple-sure you have tightened all the hose clamps, and made all the electrical connections. I filled the system with 50/50 BMW Coolant/Distilled water and bled the system following these instructions: http://www.understeer.com/waterpump.shtml I've tried the procedure in the Bentley manual, but it doesn't seem to work too well.

If nothing else, this project was good for just cleaning out that lower intake manifold. I wish I had taken a picture. There was a good 2mm - 3mm thick coating of gunk. After the cleaning, the car seems to rev smoother in the upper RPM range, and it seems to rev more eagerly.

One more recommendation. If you don't buy all-new hose clamps, make sure you oil or grease the threads on the old clamps. I've found the light corrosion the old ones get makes the clamps hard to tighted accurately. The new clamps from the dealer have a coating of oil on them.

tastade, Thank you for your input. The M44 squid is still a tough bugger, but it seem a little easier than the M42.

From memory, here's what needed disconnecting.

• The starter was the hardest, with three nuts holding on four wires. The fourth was a red battery(?) cable that got paired up with the larger wire in the squid. It helped to remove the fuel rail first and install the rail last to gain access to the starter wire. I needed to work from above and below the car to access them all.

• The alternator wires were pretty easy. Just two nuts/wire with fairly easy access.

• The knock sensors were not part of the squid. They ran to the main harness under the intake manifold. I didn't need to touch them.

• The camshaft postion sensor just plugged into the side of the squid body, so it was easy to deal will.

• One more plug into the side of the squid body, but I forget what this was leading to.?

• One plug to the DISA

• One plug to the oil pressure switch

• Four plugs leading to the fuel injectors. These were all topside, so they were easy.

• One plug to the idle control valve. Another topside easy one.

• One plug to the throttle position. Topside and easy.

• One plug leading to something on the side of the head. I think it was a temp gauge/switch of some sorts.

I'm rebuilding my cooling system right now....a few observations:

* Check the vacuum hoses on the distribution "tree" for the fuel injectors. Several of my hoses were cracked at each end. I used Goodyear 7.8mm fuel/emission hose from Autozone to replace the four hoses.

http://members.roadfly.com/anvis6/injectortree.JPG


*I have 96K miles on my car and the coolant block and head manifold were both in good condition. Water pump had a tiny bit of play in it, but looked to be in good shape too.
*Removing the throttle and cruise cable were the biggest PITA so far, followed closely by the wiring harness "squid". Not looking forward to reinstalling the lower manifold / wiring harness and installing all the connectors and mounting hardware.

The throttle cable shouldn't be hard to remove. You pull the throttle slightly open (by hand) and unclip the end. Once you have the end unclipped, you snap the cylinder on the end out from the clip holding it. The clip that was holding the cylinder on the end of the cable to the throttle actuator will come off the cable through a slit on the side if you pry it open slightly. Once this is done the cable with the cylinder can be threaded through the throttle actuator hole.

This still leaves the bracket. You slide the throttle adjuster screw out of the rubber grommet, then you pop the rubber grommet out from the bracket. Once the grommet is released from the bracket you can pull everything through the bracket hole, and the throttle cable is free to do as you please.

Here's a hose that fell apart on me. It runs from the Carbon Filter to the "Fuel tank breather valve". That then runs to the throttle body, right below the ICV. I'm not quite sure if this hose carries a vacuum or not, but it's not a standard rubber hose. Kind of a corrugated plastic flexi pipe.
http://i44.photobucket.com/albums/f2...ing/work20.jpg

problem....
everything back together....turn ignition and just get a whirring* sound from the starter solenoid- no ignition/engine won't turn over.

update: check TIS and troubleshoot: ~14Volts at battery and hot (red cable) starter solenoid. Ignition to start to measure volts and terminal 50 (small 14 ga. black wires at solenoid) and they read ~14 volts too.
Ohm meter check between battery negative & starter housing: ~0
=
replace solenoid.
UPDATE Part Deux: (I am a D*ckhead/or/don't wire ur starter after a 14 hour day & waiting two weeks to reinstall)
Got the remanufactured starter/PB Blaster soaking for about 5 hours and finally got the (2) E12 torx bolts off. In my late night wiring harness install, I had placed both "small" black wires on the post @ 11 o'clock (#30) = symptoms described above. Well, I have a nice "new" starter to go with the cooling system.

For future reference if anyone (like me) forgets where the starter wires go, here is a description.
Facing the starter solenoid from front of car:
(1) 14 ga. black wire mounts on pin at ~ 11 o'clock (#30)
(1) Red heavy ga. wire from battery mounts on large post at 2 o'clock
(1) 12 ga. black wire mounts on pin at ~ 5 o'clock (#50) below red cable.
:redface:a bit embarrassing to post...but it may help the next guy

Hmm... That's too bad. I doubt you wired the starter wrong, because it's just about impossible since all three terminals are different sizes. The big one is the only one that had two wires to the terminal. Good Luck!!

tastade's comment above..... I had the two large hot cables (battery in and alternator out)...
and the two small black wires connect to the small fitting on the left side of the solenoid when facing engine.
I don't recall a third fitting on the starter solenoid but a few posts mention that..only two connection posts IIRC....
CONFIRM the 3rd terminal??????

This is a great write-up! Thanks for putting it together.

I am in the process of doing the same project, but I'm having trouble getting the lower connector (the one on the block) to seal. What's the trick to get that fat O-ring to slide into the block?

Thanks!
Martin

I used a little bit of white lithium grease on all the o-rings... Both connectors and the water pump. If I remember correctly, that block connector o-ring made the connector push itself out. Not sure if that makes sense, but the squishiness of the rubber doesn't make the connector stay in via friction. I believe I wiggled the connector so it was flush with the block, held it tightly against the block, then tightened the bolts to hold it in position.

My Cooling System Experience
 

First off, a big thanks to CirrusSR22 for the initial write-up, and to the others who posted as well. This was my first major project on my '98 ti and the information was invaluable.

Now that I've finished this project I thought I'd share my experience in the hope that it helps others. I initially decided to do this job because my thermostat was stuck open, but I also wanted replace the plastic connector pipes and radiator before something bad happened. My car has about 98K miles on it.

Tools
A good 1/4-inch socket set is essential. Gear wrenches are nice. And I had to make my own water pump puller too.

Head Connector Pipe
Yeah, this is a difficult little bugger. I was able to remove it myself, but installation was another matter--my hands are just too big. This is where a lovely and talented assistant can be big help. I talked my wife into laying on a board placed on top of the engine. She was able to reach behind the head get the connector bolts started--I pre-connected the hoses. If you've been waiting for reason to buy a set of metric Gear Wrenches, now's the time. A 12-mm gear wrench made it a lot easier to tighten the top bolt.

Water Pump
When I tried to use the extra bolt holes to remove the water pump, the top part of the flange broke and then I discovered that the head of the bolt wouldn't clear the water pump housing on the bottom of my pump. Damn, the water pump didn't want to give up without a fight. I ended up making my own puller to get the water pump out. I kinda enjoy challenges like this.

Broken water pump flange.
http://www.2002tii-restoration.org/i...terpump_03.jpg

I welded some nuts on to a piece of 1/8 plate and cut a notch in the plate so fit over the pump shaft. I put some shims between the bolts and the timing chain cover so I wouldn't damage it. However,my first attempt at a puller wasn't strong enough.
http://www.2002tii-restoration.org/i...terpump_01.jpg

I reinforced puller with a piece of 1 inch square tube. The pump popped right out.
http://www.2002tii-restoration.org/i...terpump_02.jpg

Reassembly
I made some goofs that really cost me a lot of time.

I didn't use any lube on the connector O-rings; I should have. When I filled the engine with coolant, the block connector started leaking because the O-ring didn't seat. The 12 V battery cable messed with me too; I managed to put everything together the first time without connecting it to the starter. Doh! Oh-well, I was going to have to remove the lower intake anyway to deal with the leaking connector.

After the second reassembly, the engine wouldn't idle and was making a loud sucking noise near the injectors. I suspected that the air jacket system had a leak. So the upper half of the intake came back off and I replaced all the old hose (just like an earlier post in this thread). The hoses didn't seem to have any cracks, but replacing it helped.

This time the engine ran fine and there weren't any water leaks, but now both fuel fittings on the fuel rail were dripping. Yay! I got to take the upper intake off one more time. To get the fuel fittings tight enough, I had to put a cheater bar on my flare wrench.

The third time was the charm: The engine ran, there were no major coolant leaks, and I wasn't about to burn my car up, but I did have to tighten the radiator hoses a bit.

I'm glad I did this project; I now have heat--a good thing now that we've got daytime temps in the 20s and 30s. I've got a lot more confidence working on the intake side of the engine, and that gnarly squid doesn't scare me anymore.

Lessons Learned

• Don't forget to hook up the 12 V cable at the starter.
• Use lube on the O-rings, white lithium grease, silicone grease, whatever.
• Get the fuel lines good and tight.
• Get the hose clamps nice and tight too.

Cheers,
Martin

My pump broke exactly like yours and it was siezed in the block. I used a pair of channel lock pliers to rip it out. Took about 30 seconds. I wouldn't advise threading anything into or prying against your block. It can crack just as easily as your water pump did.

I wouldn't hammer on it either, it's designed to slide straight in and out. If you knock it crooked, you're putting a lot of stress on the block.

My car has been leaking a little bit of coolant ever since I did this. I just took my alternator off (it died :( ) and saw where my leak was coming from; the bigger plastic connector which attaches to the side of the block. It's the same one I had to force on, and the same one "martin02" had trouble with.

I'm not up for taking the whole intake manifold off, so I think I'm gonna clean the area and use some RTV silicone to seal it. Just a heads-up for those doing this project. You might want to add some sealant to both of the plastic connectors upon assembly.

Water pump FYI: make sure there is coolant added around the pump prior to starting the engine, after completing the project. If you run the new water pump dry you can damage the mechanical seal in the pump (which I think I did)
I've had a small coolant seep from the water pump and a spray pattern from it when the engines running. The water pump has a weep hole for coolant to seep out if the seal is leaking. The leak has slowed to almost nothing after the first 1,000 miles but I assume the mechanical seal was damaged during the initial startup. The Graf tech. manual says a small seep is normal in the beginning but I'm watching and waiting....crap, another $60 :rolleyes:

Everyone read this first. Water pump removal
 

Everyone read this before you remove your water pump.

On the M44 water pump, you don't need to fab a tool or use a puller to remove the water pump.

If you will look at the pump (while installed), you will notice additional threaded bolt holes. Thank god for the germans and their thoughtfulness for maintainers.

1. Remove your mount bolts
2. Use your mount bolts in the extra threaded holes
(tighten them, they will push against the block, removing your water pump with much ease)

Your welcome.

Block coolant line
 

If you happen to notice the block coolant line under the intake leaking, it would be highly recommended that you change it.

These things have been known to rot and wear over time and temp. I've seen picture after picture of these things falling apart, flange deterioration, nipple deterioration. I had this happen to me, everytime the engine temp rose above normal, the hose would blow off of it.

It's worth the money (expensive plastic) and effort to unbolt your intake and pull it back enough to replace it.

While you're at it, you might consider replacing the one on the back of the cylinder head. Both are a little hard to get to, especially on a Z3 however; well worth your time and piece of mind.

Thanks for the great article, CirrusSR22, that is quite a job. I did mine today, about 11hrs. I found the rear fitting bolts were easier to get from below. The parts list was very handy too.

I am in the middle of doing this since either a hose or the cylinder head connector gave out while I was on I-95 (good thing I was close to home!). But one thing that I have found out while removing my injectors is that the insulation on one of the injector wires has split. I want to replace it but I am having a hard time finding the part number on realoem. Does anyone here know what that part number is?

ok... I too broke the top part of the water pump off when I tried to remove it with the mount bolts.

Anyone have any other ideas on how to remove this POS w/o making the problem worse? Otherwise its going to the local BMW wrench and so they can remove it and then I'll wheel it back out and finish in his parking lot.

Stupid flimsy @ss pump... I thought these cars were supposed to be better than my Mustangs, Nothing like this has ever happened on one of them.

cooljesse said to take a giant pliers and give it a little twist in some other thread awhile back.

yeah I dont have a set of really big vice grip pliers though.... Guess I'll have to go buy some and spray it down with PB Blaster.

5litrarag

Did you try using the mounting bolts in other flange holes to lever out the pump, as in thread #23 ?? (pnchafin post)

yeah...thats how the flange itself broke. Following the removal directions. :mad:

I haven't had anymore time to fool with it yet.

Ok, i just rebuilt my cooling system and now it won't start at all :( I have an abs light and when I turn the key to start, nada, nothing. I double checked all the connections when I was reinstalling the squid, the only thing that I am questioning is the starter solenoid. I have the three prongs, 11, 1, and 5 o'clock positions (roughly) I have the two positive on the post for the two wires @ the 11 o'clock, the small ground at at the small post @ 1 o'clock and the fat ground at the 5 o'clock. Is this right? any other suggestions? My dad is borrowing my peake tool, I am going to see him tomorrow and take it back, any other suggestions? TIA

See post #13

For future reference if anyone (like me) forgets where the starter wires go, here is a description.
Facing the starter solenoid from front of car:
(1) 14 ga. black wire mounts on pin at ~ 11 o'clock (#30)
(1) Red heavy ga. wire from battery mounts on large post at 2 o'clock
(1) 12 ga. black wire mounts on pin at ~ 5 o'clock (#50) below red cable

I saw that and ended up being something else. Here is the link http://www.318ti.org/forum/showthread.php?t=22469

Did this job recently on my nearly 140,000-mile 1997 ti. In no particular order, some notes/tips:

* I removed the radiator and cooling fan immediately after draining the coolant. I'm pretty skinny and was able to stand in the engine compartment, which was a lot easier than bending over the whole time.

* The valve cover gasket was oozing and I planned to replace it, so I considered removing the valve cover before replacing the hard plastic connecting pipe at the rear of the head in hope of gaining easier access. I decided against it since it didn't seem to get me *that* much extra room, but if you have large hands, it might help. You'd probably want to replace the valve cover as soon as you're done with the water pipe, since there's still a lot of cooling and intake bits to replace at that point and having something fall unnoticed into the cam area would not be awesome.

* It doesn't seem possible to disconnect the M44 squid from the main wiring harness to leave the various sensor connectors in place while removing the lower intake. Most of the harness disconnects with screw-type quick release connectors near the engine compartment fuse box, but part of the harness (IIRC) passes through the firewall with no connectors. I didn't spend a lot of time pursuing this, so I might be missing a way around it.

* I removed the alternator to get easier access to the squid connectors and starter wiring. As a result, the only time I had to get under the car was to drain the coolant. The alternator is a bit of a pain to push out of (and back into) its mounting points, so it might be just as useful to remove the secondary air pump (toward the US driver's side, essentially next to the alternator). The air pump is a lot easier to get out and back in; just two or three easy-to-reach fasteners and it swings out of the way, opening a large space you can use to reach under the lower intake. This could also help during starter replacement, since it might be easier to access the starter's electrical connections from the top. I don't remember if the opening is large enough to remove the starter itself this way.

* Watch the tabs on the coolant temperature sensor (under the intake near the front of the block). I snapped one of mine off removing the electrical connector and decided to replace it, since it's ~US$20 and seems a bit harder to R&R with the intake in place.

* I forgot there's an upper-to-lower intake gasket on both the top and bottom of the PCV shim and only ordered one at first. Oops.

* This is a great time to lube your steering bearing (http://forums.bimmerforums.com/forum...d.php?t=245961) if your steering squeaks since topside access is easy with everything out of the way.

* I also broke one of the water pump flange ears off when trying to press it out. Reusing the water pump fasteners to press it out is tough, since they aren't long enough for the heads to clear the water pump body when you thread one of them in. If you can find them, get some long M6 fasteners to use instead. I finally stood in the engine compartment, grabbed the pump with both hands (a claw hammer or some screwdrivers to pull on the pulley flange was probably involved at some point) and rocked/pulled backwards, trying to put as much of my body weight on the pump as possible while keeping it fairly square to the block. Curse a lot while doing this; it must have helped since the pump eventually popped out.

* Getting the new pump in was straightforward; again, standing in the engine compartment and pushing into the new pump helped. As CirrusSR22 mentioned, so does a light coating of white lithium grease on all the o-rings. The water pump and both plastic connecting pipes popped right in.

* The new pump (bought from the dealer) had a plastic impeller.

* If your car has ASC+T, there's a second throttle body upstream (toward the airbox) of the main throttle body. It operates in reverse; when the actuator pulls on the cable, the throttle plate closes, blocking intake air and decreasing power output. Nifty.

* My injectors were nearly as dirty as those pictured here. I cleaned them up carefully with some q-tips and solvent and have suffered no noticable ill effects. My lower intake also had a decent coating of oil and coke; intake cleaner sprayed copiously did a nice job of cleaning it up.

* I also used the understeer bleeding procedure. I was a little nervous about this since I've heard of people who have bled and bled their cars only to still have air in the system. Some have mentioned that it helps to raise the car to help direct air bubbles toward the radiator, so I tried that first. Fill the raditor up *as much as possible* before starting the engine, since the coolant level drops *fast*. All in all, it was pretty straightforward and I probably bled more than I had to, but once I decided I'd bled enough, the car was fine cockpit heat- and engine temperature-wise. It's helpful to keep the bleeder screw mostly down (don't remove it or loosen it too much, just crack it enough so coolant can escape). This seems to help keep a little pressure on the coolant and lets the maximum amount of air escape while losing the minimum amount of coolant. I bought two gallons of coolant just in case, and only needed one. At the end, I added 3-4 ounces of distilled water only (instead of mixing with coolant) since I didn't want to crack open the second gallon and only needed a small amount to bring the radiator up to the cold level.

* Relieving the fuel pressure wasn't a big deal. I had let the car sit overnight, and I'm not sure how much bleed-back there is. Cracking the fuel line fasteners loose resulted in a smallish dribble of fuel, easily caught with a rag or two stuffed underneath the two hard lines. The Bentley manual says you can also apply compressed air to the Schrader valve on the fuel rail to force any fuel back into the tank.

* LABEL. PHOTOGRAPH. DIAGRAM. Plenty of people preach this and it seems so simple, but I always find myself wanting to skimp on this, and it generally winds up hurting me. Having a sketch of the starter and alternator wiring connections was helpful. If you think you're wasting too much time taking photos or making notes, you're probably doing the right amount. :smile:

Got to say that this tutorial was of huge assistance, as am in the middle of doing this job on my wifes 318ti, and guess what? Bang on 130,000 miles which seems to be about the limit for these connectors! I have discovered that being a RHD model, the lower inlet manifold does not require full removal from the engine bay, and therefore only minor wiring disconnection is required. I have not needed to disconnect the solenoid or starter, and the space permitted by sliding the manifold off the mounting bolts still allows me to change the connector, manifold gaskets etc.

I just replaced my water pump today and had the same problems that apparently many others have had regarding breaking the threaded tabs off of the pump while trying to remove. Thanks to Cirrus, the claw hammer trick worked perfectly and the pump came right out.

One question I did have (for anyone that cares to answer), The thermostat that I installed was a 92* (I was told that was the OEM temp) but the one I pulled out was an 88* Thyssen (apparently, the original thermostat and pump- 153k miles!!) The gauge still rides right in the center. Should I be concerned about the temp. difference?

Hey im doing an engine swap from a 1994 m42 318i to a 1995 m42 318i. How did you guys get the "squid" engine harness off without being able to disconnect it like the M44 one? I cant find where the lower wires that come from the bottom of the harness go to? How to I reach them? I was working from above so do i need to sneak in through the bottom? THANKS ALOT!!

Work Update
 

Last winter I started having trouble with very cold starts with my ti. I think I tracked it down to a vacuum leak somewhere, so I just did work to fix that. Since it involves taking the engine apart, like doing the cooling system, I highly recommend replacing the following parts while you're in there as they are rather cheap.

The goal for this project was to replace every vacuum hose and o-ring that could lead to a vacuum leak in cold weather.

Parts:
• Fuel Injector O-Rings: 13641743377 (4x)
• Fuel Line O-Ring (replace, as long as the fuel rail is off): 13531247953
• DISA O-Ring: 11611437690
• Vacuum hose between the intake boot and injector vacuum hose "Tree": 13411247782 (no ASC part#)
• 3' of Goodyear 5/16" (7.9mm) Fuel/Emission Hose, Auto Zone. Approx $1.19/ft.
http://www.goodyearep.com/productsdetail.aspx?id=10526

• 1' of Goodyear 5/16" (7.9mm) Fuel Injection Hose, AutoZone. Approx. $3.39/ft
http://www.goodyearep.com/ProductsDetail.aspx?id=5144
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I replaced the roughly 3" segment of fuel-rail hose with the Goodyear Fuel Injection hose. As you can see from the link above, it's a special high pressure, specially lined hose just for fuel injection supply. Do not use the standard fuel hose. That's for the vacuum work.

The top hose is the higher quality injection hose and the bottom is the emission hose.
http://i44.photobucket.com/albums/f23/vasa58/vac2.jpg
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Here's the new Goodyear injection hose on the left next to the little segment that connects to the fuel rail. This is an optional step, but it's worth it when you're in there. I think this hose can also be used when replacing your fuel filter. I know the hose at my fuel filter connections is in bad shape.
http://i44.photobucket.com/albums/f23/vasa58/vac1.jpg
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Next I replaced the fuel injector o-rings that seal the injector to the manifold. Surprisingly my injectors are MUCH cleaner at 185,000 than they were at 158,000 when I did the orginal project. I've been using the new BP gas with Invigorate a lot lately. Maybe that actually works?
http://i44.photobucket.com/albums/f23/vasa58/vac4.jpg
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Old, squished O-ring.
http://i44.photobucket.com/albums/f23/vasa58/vac5.jpg
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New, fresh o-ring, lubed with brake caliper grease. I hear that's a good choice for injectors since it's rubber safe.
http://i44.photobucket.com/albums/f23/vasa58/vac9.jpg

Next I tackled the injector vacuum "tree" which is getting notorious for hard, brittle hoses that crack. See elfhearse's picture above! Mine were not as bad, but were definitely starting to crack. They were also getting extremely hard.

Following elfhearse's advice, I found the Goodyear 5/16" (7.9mm) fuel/emission hose to be a perfect fit. I suggest slicing the old hoses off with a razor.

Cut replacement hoses from your 3' section of emision hose and reassemble the tree. You'll need no more than 2' of the Goodyear emission hose which will be under $2.50. You can also buy a new tree assembly from BMW for about $26. Replace the larger vacuum hose that runs from the tree to the intake boot as well.

Orginal tree.
http://i44.photobucket.com/albums/f23/vasa58/vac3.jpg
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Hoses removed
http://i44.photobucket.com/albums/f23/vasa58/vac6.jpg
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http://i44.photobucket.com/albums/f23/vasa58/vac7.jpg

New hoses fitted. The tightly bent hose is a little finicky because the factory hose is molded to that curve, whereas the emission hose kinks a bit when you bend it that tight. It takes a little squeezing/working of the hose to remove that slight kink. That's the only downside I can think of by using the Goodyear emision hose vs. a new factory tree. Thankfully you can make the curves of your replacement hose larger than the factory hoses as there's no need to make an EXACT reproduction of the factory hose. All this is doing is carrying a little vacuum.
http://i44.photobucket.com/albums/f23/vasa58/vac8.jpg
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After that, I used the remaining portion of the emission hose to replace the section that runs from the throttle body to the "fuel tank breather valve". Not sure what this valve does, but it's electrically controlled and it sits between this vacuum hose and the carbon filter.

The hose in question:
http://i44.photobucket.com/albums/f23/vasa58/vac11.jpg
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http://i44.photobucket.com/albums/f23/vasa58/vac10.jpg

Simply replace this hose with the remaining emission hose. The original hose is molded to keep it from touching the alternator. I found I needed to use a little electrical tape (or zip tie) and attach it to the bottom of the intake boot to provide clearance from the alternator.

While everything was out, I also replaced the o-ring that seals the DISA valve to the lower intake manifold. Just remove the three bolts holding on the DISA valve, use a pick to remove the old o-ring, and install the new one using some synthetic caliper grease. Make sure you clean the bore the DISA valve goes into first with a clean rag.

Also, use a pick and replace the tiny o-ring that's in the hard fuel rail connection. Probably not necessary, but might as well as you have everything apart.