Oil smoke from under the hood

malgyver · 10-20-2016, 10:43 AM

Hi all,

In the past month or so, I've been having puffs of smoke come from under the hood when I'm stopped at a light. Seems to be most obvious after I get off the freeway, but probably because I don't do much around town driving.

I replaced the Valve Cover Gasket, and there was no difference in the smoking. I have visualized the perimeter of the cover since I changed it, and its still clean.

I put the car up on ramps, and tried to poke around underneath with the bottom panel off, and its really hard to see very much under there.

I DID, however, see what is probably repeated drops of oil dripping from the front turbo V-Clamp. I couldn't find a spot on the pipes that looked like burnt oil, though.

I am ready to replace the Oil Filter Housing gasket, which is clearly leaking, but I wanted to go ahead and post the question here to see if there is any wisdom about this, because I have my doubts that the OFHG would result in oil dripping onto the manifold/downpipe. I was also resigned to replace the turbos, but since they still push hard, I figured I would try to more closely diagnose the smoking issue before diving in to replace parts.

I tried my hardest when I was under the car to inspect the whole exhaust manifold/downpipe area, but it was very tight and I could hardly see anything.

2008 335i, DPs, 120K miles, I believe original turbos that have a good rattle but still push 15 psi, loses a good bit of oil, but none on the ground.

Thanks for any insight!!

Donutz · 10-20-2016, 12:02 PM

I'm guessing your valve cover is cracked. I once had smoke come from under the hood and my valve cover was cracked.

malgyver · 10-20-2016, 01:34 PM

Thanks for the reply. I did inspect it closely when I replaced the gasket recently. Unless it can leak from a hairline crack, I think I ruled out a cracked cover.

I will, however, take a close look again for signs of fresh oil around the cover.

Any other thoughts?

TrollToll · 10-20-2016, 02:04 PM

Quote:

Originally Posted by malgyver

Thanks for the reply. I did inspect it closely when I replaced the gasket recently. Unless it can leak from a hairline crack, I think I ruled out a cracked cover.

I will, however, take a close look again for signs of fresh oil around the cover.

Any other thoughts?

Some have reported cracks that are hard to spot, even with the valve cover removed.

Donutz · 10-20-2016, 02:17 PM

The gasket could potentially be installed incorrectly. If you cleaned around the plugs and injectors when installing the gasket I would look for freshly pooled oil. This to me would be a sign that there's a crack.

One other possibility is the seal on the oil fill cap has degraded.

10-20-2016, 10:43 AM	#1
malgyver Private 16 Rep 72 Posts Drives: 2008 335i Sedan Join Date: Feb 2015 Location: SF Bay Area, California iTrader: (0)	Oil smoke from under the hood Hi all, In the past month or so, I've been having puffs of smoke come from under the hood when I'm stopped at a light. Seems to be most obvious after I get off the freeway, but probably because I don't do much around town driving. I replaced the Valve Cover Gasket, and there was no difference in the smoking. I have visualized the perimeter of the cover since I changed it, and its still clean. I put the car up on ramps, and tried to poke around underneath with the bottom panel off, and its really hard to see very much under there. I DID, however, see what is probably repeated drops of oil dripping from the front turbo V-Clamp. I couldn't find a spot on the pipes that looked like burnt oil, though. I am ready to replace the Oil Filter Housing gasket, which is clearly leaking, but I wanted to go ahead and post the question here to see if there is any wisdom about this, because I have my doubts that the OFHG would result in oil dripping onto the manifold/downpipe. I was also resigned to replace the turbos, but since they still push hard, I figured I would try to more closely diagnose the smoking issue before diving in to replace parts. I tried my hardest when I was under the car to inspect the whole exhaust manifold/downpipe area, but it was very tight and I could hardly see anything. 2008 335i, DPs, 120K miles, I believe original turbos that have a good rattle but still push 15 psi, loses a good bit of oil, but none on the ground. Thanks for any insight!! __________________ JB4, DPs, Style 313 wheels, M-Sport front bumper, Inlets, DCI
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10-20-2016, 12:02 PM	#2
Donutz Lieutenant 140 Rep 476 Posts Drives: 335i Join Date: Sep 2015 Location: Toronto, eh iTrader: (2)	I'm guessing your valve cover is cracked. I once had smoke come from under the hood and my valve cover was cracked.
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10-20-2016, 01:34 PM	#3
malgyver Private 16 Rep 72 Posts Drives: 2008 335i Sedan Join Date: Feb 2015 Location: SF Bay Area, California iTrader: (0)	Thanks for the reply. I did inspect it closely when I replaced the gasket recently. Unless it can leak from a hairline crack, I think I ruled out a cracked cover. I will, however, take a close look again for signs of fresh oil around the cover. Any other thoughts? __________________ JB4, DPs, Style 313 wheels, M-Sport front bumper, Inlets, DCI
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10-20-2016, 02:17 PM	#5
Donutz Lieutenant 140 Rep 476 Posts Drives: 335i Join Date: Sep 2015 Location: Toronto, eh iTrader: (2)	The gasket could potentially be installed incorrectly. If you cleaned around the plugs and injectors when installing the gasket I would look for freshly pooled oil. This to me would be a sign that there's a crack. One other possibility is the seal on the oil fill cap has degraded.
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