Bit of smoke

[Denholme]

Hi all. Had a look in the forum about smoke coming from the rear but will tell you what has happened. I always fill the car up with super unleaded but the wife borrowed the car for a week and ran till nearly empty. Naturally she did what she does with her megane and filled to the brim with normal unleaded prior to us heading on a 300 mile trip. I noticed on start up that morning a small amount of smoke but then that was it till about 20 mins later going round a roundabout on acceleration I saw some more smoke. I did start to panic but as I was on my way I kept going. During the entire journey I say the smoke once more so thought maybe just the fuel. Car was running fine with no issues with power, no lights on the dash. Problem is I’m now starting to panic as in my previous experience smoke is bad. Any immediate recommendations would be much appreciated. It’s a 2004 2.2se with about 94000 on the clock. Was serviced last July. Cheers

[ERX]

What colour was the smoke? I don't imagine it would be from the fuel as the z4 can run just fine on standard fuel from the pump

[Denholme]

The smoke wasn’t black or white. Would say blue ish

[Ewazix]

I wouldn't panic yet.
1. Firstly these engines do produce vapour from the exhaust when the weather is suddenly cooler or damp but should clear once the engine is hot after a few miles and is not an issue.
2. I'd check that the oil isn't overfilled, too much oil and it will get drawn in to the cylinders and burnt off.
3. If you are not mechanically minded get someone to check the crankcase breather pipes and valve are not obstructed, if they are they cause pressure in the sump and force oil to be burnt.
4. Now check your coolant level isn't leaking/dropping and there is no overheating, these cars are prone to the coolant tank developing small leaks and can cause overheating if not fixed. Overheating these engines is a big no-no and will cause head gasket failure which will show up as coolant loss, vapour from the exhaust when hot, sludge under the oil cap and more overheating.

The M54 six cylinder engine in your car should be good for 150-175+k miles without major problems providing it's been serviced properly, you would be very unfortunate to have a badly worn engine allowing oil past valve guides, my guess is it's either new-owner nerves or one of the above

[Denholme]

My mechanic mate has had the car for a few days now just sorting a rubbing on the brakes, he was going to use a diagnostic on it but as there are no warning lights could be a waste of time. Was going to get the car back and try an cleaning additive and see how that goes but with your advice it gives me a bit more info to go on. Thanks for that, as far as I’m aware the car has had a good life service wise, the coolant levels are fine and I checked the oil before we headed off that day and all was fine. I’m hoping it was a bit of fluke that day but will get the breather pipes looked at next. Again, thanks for the advice.

[Ewazix]

My mechanic mate has had the car for a few days now just sorting a rubbing on the brakes, he was going to use a diagnostic on it but as there are no warning lights could be a waste of time. Was going to get the car back and try an cleaning additive and see how that goes but with your advice it gives me a bit more info to go on. Thanks for that, as far as I’m aware the car has had a good life service wise, the coolant levels are fine and I checked the oil before we headed off that day and all was fine. I’m hoping it was a bit of fluke that day but will get the breather pipes looked at next. Again, thanks for the advice.
[/quote

no problem, keep us updated

[Denholme]

Got the car back and brakes Are sort of sorted, will need a new backplate eventually and he noticed one of my springs are on the way out. Anyway that’s off the topic. I though about being a bit proactive about the smoke and price the ccv repair. BMW Edinburgh are charging £361 and a couple of independent garages are quoting around £250 ish. I haven’t noticed anymore smoke since getting the car back but can see me taking it to get the ccv done just to be safe. The car is about 5000 under the 100k mark and I don’t have any documentation to show it’s done so thinking paying the extra £110 to get it done by BMW. Will keep you updated.

[Chris_D]

Got the car back and brakes Are sort of sorted, will need a new backplate eventually and he noticed one of my springs are on the way out. Anyway that’s off the topic. I though about being a bit proactive about the smoke and price the ccv repair. BMW Edinburgh are charging £361 and a couple of independent garages are quoting around £250 ish. I haven’t noticed anymore smoke since getting the car back but can see me taking it to get the ccv done just to be safe. The car is about 5000 under the 100k mark and I don’t have any documentation to show it’s done so thinking paying the extra £110 to get it done by BMW. Will keep you updated.

Why not have a crack at the ccv system replacement yourself if you feel up to it?
Can save you a bit of money in the process.
Have replaced systems on both M52 and M54 engine after getting clued-up. I'm not a mechanic by any stretch but it was hugely satisfying/rewarding once sorted.

[Denholme]

I had thought of it but limited with indoor space to do the job. Like I said I do have a mechanic mate and I do like to tinker with things so that may be an option if I can enlist his help. Looked at videos online and it does look doable. Seen the kit for about £45.

[mr nurburgring]

My 2.5 used to smoke, only after doing a lot of short trips, gave it an Italian tune up, changed the oil and it never came back. (5 years ago)
I guess oil deposits build up in the intake/breather system and unless worked they just build up.
I have changed my route home from work and I now use the bypass everyday so the engine sees higher rpm and keeps things moving nicely.

[Crazy Harry]

I'd say don't worry too much about fuel. I run my Zed on standard supermarket unleaded with an occasional fill of something more exotic. I used the same approach in my Focus RS which I sold at K198 plus miles having never had any engine work other than a rolling road tune! - other than of course regular servicing (and a new sump because it had had so many oil changes the threads had worn ... and before the RS my Puma which I sold at K180 again having no engine work other than a timing belt which jumped a tooth when I floored it to overtake.

If I used more expensive fuel in both cars I got a slightly better mpg (but the fuel cost more) than standard but the average 'miles per pound' was about the same. I've watched lads spend a fortune on shell super plus (whatever) for their RS's including driving about 20 miles to get it and their cars didn't do anything like the mileage I did - not surprised the money it cost them. I did a daily 70 mile commute each way when I worked and even now If I go out I can get the car hot before I get into town - one of the few bonuses of rural living. If your wife did loads of short trips and never got the car hot what you saw may just be crap burning out of the pipes or water vapor from condensation. Short trips kill cars (particularly none stainless exhausts) not mileage in my experience.

[Denholme]

That’s all good to hear, had a few issues mostly diesels mind you where they smoked and wound up having to either change turbos or inlet manifolds which aren’t cheap. Apparently there’s a chap locally to me who does a full engine flush and is a specialist on BMW,s and was told he charges anything from £60 to £160 depending on the job. Since getting the car back I still haven’t seen the smoke but keeping and eye out. Thanks for all the advice guys, much appreciated

[mr nurburgring]

That’s all good to hear, had a few issues mostly diesels mind you where they smoked and wound up having to either change turbos or inlet manifolds which aren’t cheap. Apparently there’s a chap locally to me who does a full engine flush and is a specialist on BMW,s and was told he charges anything from £60 to £160 depending on the job. Since getting the car back I still haven’t seen the smoke but keeping and eye out. Thanks for all the advice guys, much appreciated

He may have given it a bit of fist for you, blow the cobwebs away.