Smoke from the engine bay

[Timmyboybunter]

So, happily pottering around in the car since buying in August.

Would you believe, it has taken until yesterday to actually have a couple of hours free with my wife without the children - so was the first time I have taken her out in the Z4.

Naturally, she needed a good scaring so the car was driven more enthusiastically than usual. She remarked on some kind of burning smell whilst we were travelling, I confidently said it was the lorry ahead of us and we were picking up the smell (the roof was down).

Some more enthusiastic driving later and we arrived at a set of traffic lights - to find smoke coming from the engine bay. Not a massive amount, but enough for me to panic and quickly pull over to the side of the road. It was coming from the off side front wheel area/right hand side of the engine bay as you sit in the car. It smelt vaguely of burnt oil.

After it stopped smoking, I gently drove home and had no more smoke for the rest of the journey - oil level is perfect, coolant slightly low (though I haven't checked it since I had the garage change it a few weeks ago), no obvious signs of anything leaking in the engine bay EXCEPT for the washer fluid reservoir - which was full, and showed signs of leaking from the reservoir cap and also the fluid was all bubbly, as if it had been given a good shake :evil:

Could this be the source of the smoke perhaps (the reservoir is in exactly the right place for where the smoke was - if it dropped washer fluid onto a hot engine) or something more sinister?

 

[mjennings23]

If it smells like burning oil I'd hazard a guess that the rocker cover gasket is dripping oil. Due to the layout of the engine, this causes oil to drip onto the exhaust manifold, causing it to burn off and stink. Have a look at the manifold covers on the side of the engine, if they look grubby then it's likely oil dripping from the rocker above.

Had the same thing when I got mine, it's honestly an easy fix. Remove cover panels, pull the coil packs out and then 15 bolts over the cover. Prize it off, replace gasket, job done

 

[Chris_D]

If it smells like burning oil I'd hazard a guess that the rocker cover gasket is dripping oil. Due to the layout of the engine, this causes oil to drip onto the exhaust manifold, causing it to burn off and stink. Have a look at the manifold covers on the side of the engine, if they look grubby then it's likely oil dripping from the rocker above.

Had the same thing when I got mine, it's honestly an easy fix. Remove cover panels, pull the coil packs out and then 15 bolts over the cover. Prize it off, replace gasket, job done

+1.
I'm almost so confident that it's your cam cover gasket leaking that I'm willing to bet my cat's dinner on it!
:lol:
Easy fix. I have a monster thread relating to my own experience if you can be bothered searching it out....

 

[Timmyboybunter]

Thanks both - I do have a small leak from the rocker gasket, but it's just enough to leave some residue on the side of the engine, not enough to cause all that smoke out of no-where, but perhaps you're right - it needs changing either way. My garage is going to give it a quick check on Thursday so I'll report back.

 

[andyf1140]

It's probably the vacuum pump that's at the back of the head on the driver's side, when it leaks the oil drips quite nicely onto the catalytic converter and the smoke will come out from under the car just behind the front wheel. It's actually an easier fix than the cam cover gasket and cheaper parts wise as well. The other thing to consider is that if the CCV has not been changed it may be blocked and it is probably what has caused the vacuum pump to leak.

Beware if it is the vacuum pump that is leaking it does not mean that you need a new pump it's possible to get the oil seals to repair the pump which is easy to do.

 

[scarlet-jester]

I think I may have this problem too.

I have no visible smoke but once up to temperature, there is a distinct smell of burning engine oil

 

[kis]

Another one for rocker cover (even tho already solved - for the benefit of others in the future using search). Mine stands for a week or two before it's used sometimes and this means there is a small amount of oil that leaks and then is burn when you drive. Only noticeable when up to temperature, so it can burn. Obviously, if it was a daily the oil produced would quickly be burnt up so a leaking gasket might not be noticed until left stood for some time (so it can accumulate). Hope that makes sense! My smoke comes from the left side of the engine bay when looking from the front of the car (same as OP).

 

[Timmyboybunter]

Thanks all, I'll run this thread past my mechanic when I drop it off tomorrow.

 

[Timmyboybunter]

Well, the garage had a different theory. On removing the engine covers, they found oil present in the front couple of sections on top and believed it may be seeping up through the first (the front most) rocker cover screw - so have cleaned it all up and re-seated, will now keep an eye out for signs of any new oil present. Rocket gasket apparently ok.
Excellent garage, they'll turn their hand to anything - including doing my CDV delete a few weeks ago based on my description only, they've even remapped my Octavia unfortunately the Zed came back from them at the beginning of this week with 2 new 4 inch parallel scratches on the front bumper which I'm gutted about. Bit awkward, as it's a classic 'my word against theirs' scenario but they do seem genuinely baffled how they may have gotten there - and offered to fit a new/2nd hand bumper for free if I can source one (mine is quite damaged under the front lip so seems silly to attempt a scratch repair) which is a reasonable gesture - as I guess it could genuinely be something outside their control like another clumsy customer. Shame though.

30 mile enthusiastic drive tonight, no oil smell or smoke so time will tell.

Thanks all for the input.

 

[kis]

This is interesting as the screw is independent of the engine.
i.e. if the oil is leaking through the screw, engine oil must first come through the rocker cover gasket :?

 

[Timmyboybunter]

Ah, I may be explaining what they told me incorrectly as I didn't actually see the engine - they said there are 4 or 5 screws on top of the engine, 2 (?) of which hold the engine covers to the top of the engine, once the covers are removed, the remaining screws - each with a rubber seal - then hold the top of the engine in place.

I'm clutching at straws will probably take the covers off and have a look myself - apparently there are several chambers exposed, the front couple of which had oil in them. Trying to find a picture of the engine with covers removed so I can understand but failing.

 

[kis]

Full video below.

https://www.youtube.com/watch?v=TCbOHO-KALY

All screws, etc. Will have the rocker cover as a barrier from oil... so either the gasket requires replacement or hasn't been fitted properly. In all honesty, if it's the latter it could probably do with a replacement as may have deformed, etc.

 

[patriot66]

Engine oil cannot leak up through the two bolts that hold the top 'BMW' cover on. They are blind bolts moulded into the plastic of the cam cover as can be seen circled in this photo taken when I replaced my gaskets.
If there was any amount of oil in the 'chambers' between the spark plug holes then it must have come from the gaskets that seal the top of the spark plug tubes to the cam cover or the 4 bolts in a line between the spark plug tubes. You can see the gaskets in situ and the underside of the cam cover in this photo.
My Zed was leaking oil from the back drivers side corner which was burning off on the exhaust manifold cover as can be seen in this photo.
If I was you I would replace the cam cover gasket complete. It is an inexpensive and easy task.

 

[Timmyboybunter]

@patriot66 thanks, you've provided the words I've been struggling to remember when at the garage yesterday

It's the '4 bolts in a line between the spark plug tubes' that they think was the source of the leak, specifically the first bolt closest to the front of the car.

I'll keep an eye on it - I was half surprised that the rocker gasket may be leaking even though I could clearly see evidence of oil coming from somewhere, as the previous owner (who was a mechanic) changed it at some point in the last couple of years. I've asked the garage to send me on the photos they showed me yesterday so I'll add them here if I get a reply.

 

[patriot66]

@patriot66 thanks, you've provided the words I've been struggling to remember when at the garage yesterday

It's the '4 bolts in a line between the spark plug tubes' that they think was the source of the leak, specifically the first bolt closest to the front of the car.

I'll keep an eye on it - I was half surprised that the rocker gasket may be leaking even though I could clearly see evidence of oil coming from somewhere, as the previous owner (who was a mechanic) changed it at some point in the last couple of years. I've asked the garage to send me on the photos they showed me yesterday so I'll add them here if I get a reply.

 

[Chris_D]

I would simply be replacing the rocker cover gasket and cleaning up any residual oil which may have collected on the underside of any drip paths/surfaces.
I recall when I replaced my gasket that it was still smoking like billyo which led me to falsely believe there was still a leak somewhere until it all burned off. Been leak-free happy days since.....