Rough idle for 40 seconds followed by white smoke

[applefan]

Jess Thanks for all the help.

I checked heater this evening. It blows hot air even while the car is idling.
I rented a radiator pressure tester from autozone. Will use that to compress and do the test you described above

[applefan]

Another update:

I tried a cold start this morning and evening ( didn't drive), there were no rough idle. I will wait for few more days and few more starts before confirming the rough idle issue fixed for sure. Looks like the valve cover gasket and spark plug replacement , along with the cable/cluster cleaning did the trick.

Thanks Jess and Jim ( and anybody else I missed mentioning) for your valuable help!

I filled up coolant again and going to keep and eye on it. Will get to the rest of the tests after confirming a genuine coolant disappearance

[tiFreak]

Originally Posted by cooljess76

I wouldn't take it past 5psi though, you don't want to make things worse by overpressurizing it.

a lot of cooling systems run about 15 psi, not sure what the ti system runs at but it should be good at least up until that. I've seen cars with coolant leaks that can hold 5 psi no problem, sometimes you need to go over that to see the leak

[cooljess76]

Yeah, I think out radiator caps are set to relieve at 15psi. So between 5 and 10 should be fine.

[applefan]

Update: every 100 miles trip I make, coolant level goes down an inch or two ( on the radiator reserve tank). also when I fill up the tank all the way, I can see the exhaust puffing white steam. I am going to bite the bullet and change the head gasket this weekend. I already have most of the parts and tools. The HG kit I bought is VictorReinz. I saw some posts saying, use everything int the VR kit, except the VR head gasket itself and buy a genuine BMW head gasket instead. Is that still true or that was a problem in the past ?

[applefan]

Another interesting finding : - Last night I was checking the coolant level and it was all the way at the bottom of the tank. Was going to fill up again and when took the radiator cap off, coolant came back to the tank all the way to the top of the tank. didn't fill any coolant, just closed the cap and when started this morning, no more rough idle.

Does this mean the excessive pressure in the cooling system causing the coolant to leak into the cylinder overnight and causing the rough idle?

[J!m]

Have you tried another cap on the tank yet?

Sounds like (from that description) it is not working properly.

[applefan]

no I haven't tried another cap. Will try another cap tonight. Jim, Thanks . I never thought about it.
didn't know the cap regulates pressure either.

[cooljess76]

Originally Posted by applefan

Another interesting finding : - Last night I was checking the coolant level and it was all the way at the bottom of the tank. Was going to fill up again and when took the radiator cap off, coolant came back to the tank all the way to the top of the tank. didn't fill any coolant, just closed the cap and when started this morning, no more rough idle.

Does this mean the excessive pressure in the cooling system causing the coolant to leak into the cylinder overnight and causing the rough idle?

The dye kit you purchased was supposed to be used with this tool, not poured into the radiator:
http://compare.ebay.com/like/2308122..._lwgsi=y&cbt=y

http://www.handsontools.com/Lisle-75..._campaign=BROI

Did you do a leakdown test? How about a radiator pressure test? You definitely have a lot of air in the system and it needs to be bled properly.

[ryszardsh]

If you look the cap it will be marked at the pressure it is supposed to hold - 5.5 Bar or something like that. It does so with a spring and a gasket, hole in one or wear on the other and pressure on the cooling system is incorrectly held.

RAS

[applefan]

This is exactly what I rented from Autozone along with the blue liquid that changes color. did this test 2 weeks ago - turned out negative. ( the dye to pour into the coolant was different. i didn't buy that )

Originally Posted by cooljess76

The dye kit you purchased was supposed to be used with this tool, not poured into the radiator:
http://compare.ebay.com/like/2308122..._lwgsi=y&cbt=y



http://www.handsontools.com/Lisle-75..._campaign=BROI

Did you do a leakdown test? How about a radiator pressure test? You definitely have a lot of air in the system and it needs to be bled properly.

didn't do the leakdown test and radiator pressure test, as the exhaust gas presence test turned out negative.

[cooljess76]

Do the radiator pressure test, I bet you'll find something. Probably a cracked radiator. Follow up with a few cycles of bleeding the system:

http://www.318ti.org/forum/showthread.php?t=27983

When you're doing the radiator pressure test, do it in a closed environment such as a quiet garage so you can hear and track down any hissing from air escaping the system.

[applefan]

Originally Posted by J!m

Have you tried another cap on the tank yet?

Sounds like (from that description) it is not working properly.

I bought a new radiator cap from Kragen last night. They didn't have the 30psi one, but 20 psi.
The existing one rated 30psi ( this came with the Behr radiator I bought from ebay 2 years ago) , but thought will give the 20 psi a try

There were no rough idle this morning. Drove it to work , 45 miles, coolant level is just above the mid of the tank ( marked CALD?), unlike all the way down when using the old cap.
fingers crossed....

[applefan]

I bought a radiator cap from the dealer with the correct spec ( 30psi), coolant level went all the way down on the reservoir tank. - So it doesn't look like a bad cap issue

Next in the list- Radiator pressure test:
Went to autozone . None of the radiator pressure tester kits have a matching cap for BMW

I saw one kit at harbor freight for $80 . Anybody tried if this works on a BMW? - review of this product doesn't look good either.

[cooljess76]

Sigh...

Why not just do what I said and use your old cap now that you've wasted money on a new cap. get a shrader valve from your local tire shop(they'll probably give you one for free) or go to your local bicycle shop and ask for a tubeless rim valve stem(they're made by Mavic wheels and cost a few bucks), then drill a hole in the old radiator cap slightly smaller than the valve stem, insert the valve through the hole in the cap and use a bicycle pump to pressurize it up to 5-10 psi. Throwing random parts at something is never a good route to take. It's not my money so I shouldn't even care, but I just feel like I'm wasting my breath posting this stuff.