Atcpup

2008 S550 with 45k miles. It has blown a fairly good size of smoke twice now. Both times the conditions were similar. The first time (a month or so ago) I backed the car out of the garage to wash it. The car was cold, meaning it had not been run in several hours. After about an hour, cranked it and it blew a noticeable amount of what looked like white smoke. Ran it around the block and up to operating temperature, could not get it to do it again. Fast forward to today and it did the same thing. Backed it out of the garage and had to cut it off to run back inside to do a few things. Came back out in 5 minutes, cranked it and blew the white smoke again. This time I jumped out to smell it. It had a very rich smell to it, not an oil smell. Any ideas what this could be? I'm thinking an overly rich condition?? The common denominator is a cold motor being shutoff and re cranked. I find it hard to believe that the computer can not adjust for this condition. It is not blowing smoke under any other conditions. Any ideas on where to start? Please don't say the dealer, I know that is an option. Just looking to pick the brains of some forum pros here.

Thanks!

platt-deutsch

Coolant?

phatisfy

I get that problem sometimes too when I leave the car sitting long.

cool_lagoon

check tail pipe with finger and feel if there are oil residue, if yes it's a blown piston ring, if the white smoke disappear it can mean moisture during cold start then that's nothing to worry about, on mixture of air and fuel, it is controledby control modules inside the computer box, if white smoke does not disappear then you start worrying. you might want to check the oil stick to check if you have water contamination in your oil (milky color will turn out if contaminated with water).

phatisfy

Thanks for the info. Yea, mine goes away after a few minutes. whew!!! I got nervous for a second.

Atcpup

Not sure if I follow you when you say "disappear". The car blows a puff of smoke out, but not continuously. That puff is carried off by the wind. It's not the smoke you see on a cold morning when the car is warming up. The tail pipes are not oily nor does the oil stick indicate anything abnormal. Its happened twice. Both times the car was cranked while cold then shutoff less than a minute later. It blew the smoke when the car was cranked a short time later. It happened only under those exact conditions, no other times. I am thinking it is cold start rich condition or the moisture you mention from not doing a full warmup.

cool_lagoon

if the white smoke persist to blow continually then you have a blown water seal jacket or a blown cylinder head gasket on your cylinder head, you need top overhaul for that to be fixed. now if it is burning oil which can be tested by touching the inside of the tail pipe for signs of oil, then that would be the piston rings. the car unless properly maintained should not have those issues. This models do not have much headache on the engine as well as engine management system, but when it comes to the fuel system, suspension system, electrical accessories this are the water loo, and the main nemesis of this series are fuel grade and filters, otherwise this is almost as good as the W126 series. The worst was the W220 then the W140 (due to wire harness factory defect).

hyperion667

that happened a couple of times on my amg too, puff of white out back, but it went away and has not done it since, my indy guy said it's normal in chilly conditions

good luck

Bobsbenz1952

I recently purchased a 2008 cls 550, originally it is from California. After having it a couple of weeks, I noticed a miss in the engine. I changed the spark plugs but that did not help. This vehicle has 78,000 miles. I finally took it to my MB dealer in Naples Florida. They did a compression test and some of the cylinders had low compression, due to defective cylinder heads. My service advisor said this is very rare with this engine. He also said there was a service bulletin from MB about these defective CH's. The repairs to replace them will cost 7000.00 which is a real big disappointment to me. As of today 12-5-2015, I am waiting for new heads found only in Germany. Now this past week, I drove the car for about 20 minutes. When I came home I shut the car off and and let it sit for maybe an hour. When I started the car again I noticed a puff of white smoke from the exhaust. The miss in the engine is not severe and the car still seems to have plenty of power. Also I cannot find any service bulletin on this topic. Please if anybody is familiar with this problem please advise me. I greatly appreciate any help I can get. Bob

xxfightclubxx

the heads can just be resurfaced you dont need to buy brand new ones. look into machines shops that work specifically on heads and motors. good luck.

Bobsbenz1952

Thanks for your suggestion. The SA told me that the holes ( I'm not a mechanic) the valves travel up and down through, get wore out so the valves just flop around when the engine gets hot. He told me that there is a service bulletin from MBUSA concerning this problem. I cannot find SB anywhere. Thanks again for your help. This is why I need new heads.

Nickthegreek

If it only happens for a few seconds on cold start that is totally normal. When you first start an engine cold there are 2 things:

A)the piston rings are cold and have not expanded yet and do not seal 100%.

B) the computer is in what is callled open loop mode. In open loop mode it does not use the input of the O2 sensors because they need to heat up to a certain temp before they can start working, so the computer uses what are called substituted values. It is programmed to run slightly rich from a cold start in open loop to avoid knocking and predetonation.

If you smell burning oil and there is blue smoke that keeps coming out even when at operating temp then your rings are not sealing at all and there is an issue. The rings are just contracted when cold and allow some blowby smoke and then as they get hotter they expand and seal better. This is how the car was engineered otherwise the rings would scrape against the cylinder too hard

A common issue in cars that can be mistaken for bad rings is the ring getting caught in the groove due to carbon deposits. It shows as a bad compression but after allowing solvent to soak in the combustion chamber overnight it frees the rings and then the issue goes away.

What you have described is totally normal. The only reason you notice it on a cold day is that theres water vapor in with the oil in the smoke.

alx

this

Jason B

I've had this happen on numerous cars. Usually after sitting for a while in the garage. Back it out to wash it, then white smoke. Only has happened a handful of times over the years to quite a few cars. Hasn't happened with the S yet.

Atcpup

This happened shortly after purchasing the car. Haven't seen it since, about 60k miles ago..