Burning smell from under the hood.

[Drexel]

Hey guys. I need some help here regarding a burning smell that's coming from my 2004 Z4 3.0i.

A couple of months ago I noticed a faint burning smell coming from my car. This was in the summer months when I would drive it on a regular basis. At first I thought it was nothing... I figured it was from the environment around me, or other cars. Then I started to notice that it was pretty persistent, and after parking in garage I could really distinguish this aroma of what might smell like burning plastic, or some other synthetic material.

The smell hasn't gone away. I've taken it to two shops now and neither of them are able to tell me where it's coming from. I had the oil filter housing gasket replaced last year when it started leaking, and neither shop was able to identify any leaks or liquids that might be burning off anywhere under the hood. In September one of my ignition coils went and had it replaced (I thought it might have been that), but that didn't fix the problem. My regular mechanic thinks it might be carbon buildup burning off, but really, is that a thing?

Today I took the car out for what I think will be my last drive of the season. I put some fuel stabilizer in it and drove for about 20 minutes to my parents house. When I got there I smelled burning again, so popped the hood, and since it's now so cold here in Toronto I saw a lot of smoke/steam coming from around the left side of the engine (passenger side here in Canada), close to where the sheet metal wraps around it.

Any idea what this might be? I'm worried now that something vital is burning and I don't want to believe it's just "carbon buildup burning off". My fear is obviously catching fire while I'm driving, or a breakdown or my engine blowing.

Any help would be GREATLY appreciated!!

http://www.z4-forum.com/forum/download/file.php?mode=view&id=9324

http://www.z4-forum.com/forum/download/file.php?mode=view&id=9323

http://www.z4-forum.com/forum/download/file.php?mode=view&id=9323

 

[Drexel]

I found a thread here where they're describing pretty much exactly what I'm experiencing!

http://www.z4-forum.com/forum/viewtopic.php?f=2&t=81049&p=1194667&hilit=burning#p1194667

The YouTube video posted in that thread seem to indicate the same, but there's no solution posted.

 

[Chris_D]

Sounds like exactly what ive been through- i'm not a betting man but i'd be willing to wager that your cam cover gasket needs replacing, as also suggested in your quoted thread.
Oil usually seeps out of the rear lowest corner and drips down onto the exhaust manifold causing the burning smell.
When the motor is cool have a feel around that area for seepage. You may have to loosen the heat shield a little to get your hand around the back of the head.
Cheap easy fix.
Good luck

Edit: dug up one of my own old threads where you can see my own cam cover gasket replacement details.
http://www.z4-forum.com/forum/viewtopic.php?f=3&t=90194&hilit=Betty&start=60

Keep us posted re ur own progress....

 

[Drexel]

Thanks Chris!!!

I'm gonna be dropping by the shop tomorrow to take care of the brakes on my SUV. I'll mention this to my mechanic and see what he says. If possible I'll try to swing by next week with my Z4 to see if they can look into the problem and identify if this is in fact what's causing the issue.

I really appreciate the input! At least there's others out there who have run into the same issue.

My one big question is, how dangerous is this? Would it be safe to store my Z4 for the next 5 months and then take it in to get fixed or does it need attention right away?

 

[Number5]

Also, if you've topped up the oil recently and spilt some, it will run under the rocker cover and then only when the engine is warm, it runs to that same back corner and drips onto the hot manifold.

Pop the enginer cover off and have a mop around.

You havent said what the burnng smells like. - Oiily smell or plastic. Acrid and plastic I'd be far more worried.

 

[Lance]

I've had a similar issue for most of this year now and after a bit of digging about under the bonnet confirmed mine to be a weeping cam cover gasket, with the odd drip of oil making it's way down to the hot parts, hence the smell. Laziness and other life things to do meant that I have put this rather simple fix off and off and now it's freezing here in the UK and it will have to wait for a mild day (or probably springtime). The parts are cheap, around £50 I believe and it's only an hours work to swap to a new gasket (there's a video on you tube).

Dangerous? IMO no! Store and fix next spring, again IMO this would be fine.

Cheers

 

[Chris_D]

Thanks Chris!!!

I'm gonna be dropping by the shop tomorrow to take care of the brakes on my SUV. I'll mention this to my mechanic and see what he says. If possible I'll try to swing by next week with my Z4 to see if they can look into the problem and identify if this is in fact what's causing the issue.

I really appreciate the input! At least there's others out there who have run into the same issue.

My one big question is, how dangerous is this? Would it be safe to store my Z4 for the next 5 months and then take it in to get fixed or does it need attention right away?

Not so dangerous as this common problem tends to produce only a small amount of oil leakage.
The gasket hardens over time and this causes the leak. The gasket s ctions around the spark plug holes also harden and the forward section on mine cyls 1&2 hardened to point where oil had seeped into the spark plug hole for cyl 1 and fouled the threads but thankfully not the plug itself. Something to bear in mind perhaps.
If you follow my quot d thread youll see that i still had smoking and a burning smell post-replacement but this was just oil reaidue still on the manifold burning off. No problems now as its all burned off. Its an easy enough DIY if youre confident enough.
Good luck

 

[eleflo]

Hi, not sure if it helps but I had the same a few years ago on my 2.0L, it was the vacuum pump at the back of the engine leaking and dropping onto the exhaust, at first it did look like the cam cover gasket (at there was oil on the metal shelf) but it turnout to be a leak from the pump, might be worth a look.

 

[csquire4]

I had same problem with E39 3.0 and it was rocker cover gasket. It was at it's worse when on an incline and then pulling off, basically, a drop of leaking oil drops on hot manifold and then burns off (I was getting smoke in the cabin).

The second time I got the gasket changed I used a BMW one and also changed the rubber washers (I think there are 15 of them about a £1 each) which seemed to do the trick.

http://www.bestpartstore.co.uk/1881767


If this doesn't fix it it could be that the rocker cover is cracked or warped.

Good luck.