Rough idle for 40 seconds followed by white smoke
 

Hello - 96/318ic/175k miles/auto It all started with a rough idle on cold start for 40 to 60 seconds and then everything is normal (very famous problem in this forum with no knowN fix!, other than replacing everything under the hood)
Finally when I was revving up the engine one morning, noticed white smoke in the exhaust
Checked coolant level - its dropping for sure
Checked dipstick and oil filler cap - no signs of coolant in the oil
Exhaust has a smell of burning wood. Not sure if it smells like coolant, but doesn't smell like pure gasoline

Car is definitely losing coolant, although there is no leak in the cooling system

Can it be a blown head gasket? Is it possible for the coolant to enter in the combustion chamber before mixing up with oil. Coolant in the cylinders may explain why the rough idle for the fist 40 seconds of a cold start?

Any help/suggestion is greatly appreciated

Sounds like a bad head gasket to me.

Oil passages and water passages are around the cylinders and one (or more) of the water passages is now open to one (or more) of the cylinders.

If an oil passage opens to a cylinder, you burn a lot of oil.

If the water is open to the oil, you get water in oil (or vice-versa).

Based on what you are describing, you have a water passaage open to the cylinder.

Head gasket required, cooling system rebuild, proper bleeding after adding BMW coolant and distilled water mix... Do a search and you will find what you need to do it correctly.

Jim, thanks for the reply
I was always under the impression that a blown head gasket will cause coolant to mix up with engine oil. Thanks again for the explanation on this special situation

I did a complete cooling system rebuild 3 years ago and cooling system still going solid, so this time it's going to be just HG. Going to order HG kit from autohausaz Will be following Bentley manual

While I go that far, anything else should be replaced inside or outside the engine?

There are actually three ways it can fail: water and oil mix; water in CC; oil in CC; inter-cylinder failure (small gasket area between #2 & #3 going bad allowing compression from one to leak into exhaust of the other for example). The last needs a leak down test as well as compression test of all cylinders to isolate, and can sometimes leak one way but not the other, which can look like bad rings in one cylinder...

I hate the Bentley manual. It is best used as a wheel chock or to absorb oil spills. Chilton is the best of the 'generic' manuals, but still leaves a lot to be desired. You can find the BMW TIS manual on-line to read (free) and I suggest you do so. I think you can also print pages.

The bores should be carefully checked. More than 0.001" wear at top ring reversal is cause for opening the bore (honing) and fitting over-sized rings and/or pistons if the wear is excessive. That is assuming you want to keep the car for another 100K or more. If you cannot measure accurately (you need a bore gage) see if you can still see the honing marks in that top ring reversal area. If so, you are probably fine.

Have the head checked for flatness while it is off. If it is out of allowance, it will cause the HG to fail again.

Maybe consider a timing chain, but they are not prone to excessive stretch on these cars as far as I am aware. Reassembly and reverifying cam timing will make up for any stretch and 'pep up' the engine as will the new head gasket.

I think you need new head bolts too. If I am not mistaken, these are torque angle spec bolts (the S52 is for sure). So you tighten to a specific torque and then rotate a specific number of degrees after that. Because of this they stretch, and I think are allowed to be re-used once (others may know for sure) but it is generally a good idea to just get new ones, clean and oil the threads (chase the threads in the block too!) and torque properly to prevent the gasket from failing.

Also: MAKE SURE YOU TAKE THE HEAD OFF FOLLOWING THE TORQUE SEQUENCE BACKWARDS to avoid possibly warping the head during removal. It is a common mistake, and easily avoided.

Others can chime in with more if there is anything...

Best way to diagnose a BHG is to perform a leakdown test. You can also test the coolant for exhaust gasses. Your local auto parts store should sell both test kits. Best of luck to ya.

Good point. Thanks Cooljess

I am trying to get these two special BMW tools for the Head Gasket work
11 2 300
11 3 240

Called dealer and cost is around $500 each!!! I read some where people using a tool in the tool box that came with the car. Any advice? I would rather give to a mechanic than spending $1000 for this tool + HG kit and all my work

Not sure which tools those are, but if you need cam blocks the Haynes manual has a template to make your own on page 2A-3. There's also a thread in the knowledge base with instructions on how to make the rigid timing chain tensioner and flywheel locking pin.

Edit; here you go:
http://www.318ti.org/forum/showthread.php?t=11334

Awesome!! Thanks cooljess. You saved me a lot of money and trouble

I did a compression test over the weekend and all 4 cylinders come out with the same reading around 140 ( don't remember the unit) on 4 cranks.
I may need to try another method of test to make sure it is absolutely a BHG ?

While I was pulling the spark plug out, noticed the plug #2 was filled with oil till the connector end. Looks like I need to replace the Valve Head gasket, but that doesn't explain the rough idle and white smoke?

Dude I think you may have dodged a bullet. Yes it does explain the rough idle. Your engine was misfiring because the plug wire was submerged in oil. This is a common issue on these engines. You need to replace your valve cover gasket and spark plug seals. IIRC, they're sold as a kit. Now theres a couple things you should do. Hopefully you soaked up the oil with a shop towel BEFORE you removed the spark plug to do the compression test. If not, all that oil is now in the combustion chamber and your car will smoke like crazy, probably foul the spark plug, possibly the o2 sensors and gunk up the catalytic converter. You can remove that spark plug and crank the engine over a couple times. This will blow most of the oil out of the cylinder. Next you're gonna want to clean the oil out of the plug wire connector. Best way to do this is to use brake cleaner. Don't use carb cleaner as it will dry out the rubber. Spray it out really good with brake cleaner and allow it to dry completely. TAKE A FEW PIECES OF MASKING TAPE AND NUMBER THE PLUG WIRES ONE AT A TIME.

When you remove the valve cover to replace the gasket and spark plug seals, there's a hose towards the back on the driver's side of the valve cover that goes to the CCV. Remove that hose from the valve cover, then spray some brake cleaner through the orifice that the hose attaches to on the valve cover. It gets gunked up over time.

When you reinstall the valve cover, double and triple check that the spark plug seals don't shift or fall out of position. You want those things to seal up really nicely. And finally, it's very important to torque the valve cover down exactly as outlined in the manual. If you don't already have one, buy a Bentley manual. At the very least, buy a Haynes manual if the Bentley is out of your budget. Use a torque wrench, the cylinder head can easily become damaged if you don't.

Let's keep these details in mind. The oily plug does not help the situation; however there may still be a problem, particularly if the cooling system is only a few years old...

Cooljess and Jim. thanks, You both have a point . I think cooljess, your theory explains the rough idle issue . The oil leak need to to be fixed for sure. Missing coolant still bothers me. I still suspect the BHG for the coolant missing issue. Is there any other test I can do to rule out a BHG?
The guy at local autozone showed me a dye that I can put in the coolant to detect leak, but not sure if that will help if the coolant gents into the CC ? You think the color of the exhaust will change if I do this test ?

Generally a compression test is not what you would do to diagnose a BHG. Instead, you'd want to perform a leakdown test. If oil was leaking into the combustion chamber, you'd see bluish-white smoke. If coolant was getting in, you'd see cloudy white smoke and notice a sweet smell. I've seen the dye test however I've never tried it. I'm assuming that they dye has a chemical reaction to exhaust gasses and the coolant will change colors if exhaust gasses are detected. I could be wrong though.

FWIW, I was losing coolant for almost a year. It started out, just a little at a time, then it got to the point that I was losing almost a gallon a day. That's how I became so good at bleeding the system, lol. Everyone was telling me that I had a BHG although my car was running great, no smoke, no coolant-oil mix, and I had put over 10k miles on it since the coolant loss was fisrt noticed. Turns out I had a hairline crack between my radiator and expansion tank which progressively got worse. Coolant was leaking out so slowly that it would evaporate before it had the chance to even drip. I found the leak by rigging up a schrader valve to an old radiator cap and using a bicycle pump I pressurized the system to about 5 psi. The car was parked in my garage so there was no distracting noise. I traced the hissing down to a crack between the expansion tank and the side of the radiator. So yes, you may have two separate issues going on and the coolant loss needs to be identified.

Another thing to consider is the possibility that maybe you purchased some bad gas. You can remedy this by adding a can of seafoam to a full tank or at least 8 gallons of fuel. The seafoam costs about 7 bucks a can at your local auto parts store and it will mix with any moisture in your fuel system and make it combustable.

How do I do a leak down test ? is it something I can do myself or better done outside for accurate result?
does the leakdown test procedure in the link below explains the correct procedure?
http://www.pelicanparts.com/bmw/tech..._rebuild-1.htm