Intermitent smoke from behind my engine

[Bimminator]

I have been noticing an intermitent burnt oil smell for some time now. Was constantly looking for slicks under the engine after being parked, and have never seen any brown or black stains in the snow either. Recently while checking for vaccum leaks I noticed little puffs of white smoke rising from between the rear of the motor and the firewall. My mechanic says the rear seal has a slight leak and since my oil level is not dropping abnormally I shouldn't worry about that much as it is kind of a costly repair. I don't think I want to put up with intermitent burnt oil smell inside the car all summer so may fix it sooner than later.

Any thoughts?

[Kalevera]

What motor?

If it's an M30 -- I've noticed that the valve cover can leak at the gasket (feel around there with a towel when the engine's cold and see if anything gets sopped up) if the gasket hasn't been replaced when the valves are adjusted.

Best, whit

[Bimminator]

It's a 535i, and i di have a valve adjustment about two months ago but Im not sure if they replaced the gasket? I will check with a towel in the morning though, thanks.

[Kalevera]

Either way, if you have access to a 10mm (? -- maybe it's a 13mm, I forget) socket and a small extension/ratchet, it might be smart to just tighten up the castle nuts.

But yeah, the valve cover gasket will leak (mine did it at the rear of the block...which sounds like what's going on with yours) after I pulled the cover ~ 2 times and didn't replace the gasket.

best, whit

[Bimminator]

Thanks, I hope that is the issue I will try that

[peks]

if you spilled a little oil on the exhaust manifold gasket/heatshield deal just below the oil fill hole it will stay there forever and smell like burning oil when it gets hot.

[Bimminator]

Yeh, there could have been some oil slopped around in there, I didn't do my last couple of oil changes so who knows if any was slopped. Would engine degreaser liberally applied clean that adequately enough?

[peks]

i tried that but never had a chance to see if it helped. didthe clutch a couple days later and pulled the manifolds off and replaced the gaskets while i was in there. the rear one especially just crumbled away.. probably just many years of oilspills and heat. it was shot.

[epj3]

this thread is ironic (to me...), I just did an oil change today and let the engine run to warm up a bit, and i had the hood up looking around checking for everything, and noticed this smoke too! Doesn't really smell but I had the same thing on my e30. I think it's either the valve cover leaking (...just did a valve adjustment last week, so maybe I didn't tighten it enough), or the exhaust is leaking (which was the e30's problem...though my m30 is much healthier than the m20 in my e30 was)

[peks]

exhaust could be leaking from the joint at the bottom of the header too