Oil Leak (s) + burning oil smell

[TenaciousC]

Hi All,

Have noticed burning oil smell after changing oil recently. There seems to be two possible areas of interest (which may be two seperate issues).

1. Oil seems to be on the compressor side of the turbo, though feed hose seals all look OK.

2. More disturbingly was the large presence of oil on the main back coolant feed pipe of the engine. Higher, was oil at the bottom of the exhaust manifold of cylinder 1 , and this looks to have dripped from here onto the coolant pipe.

I checked the above the manifold and could not find any evidence of a leak from the top section of the cylinder head.

These other points may be relevant to a diagnosis:

• Engine running well, no misfires
• Oil consumption seems to be increasing
• No oil has dropped onto drive under car (yet)
• No blue smoke on startup or running (as far as I know)
• 4W/40 fully synthetic oil used
• No oil on spark plugs of cylinders 1/2 ... although a little oil on top of plug of cylinder1

Sorry for the lack of pictures. Any ideas what I might be dealing with here?


Thanks as ever

C

[mikealder]

Take the top cover off the engine (the black plastic part) and have a look if there is oil under that, did you spill any oil when you last topped it up/ changed the oil, double check the condition of the filler cap seal as these tend to harden then they leak. Finally check the PCV, with the engine up to temperature and running pop the dipstick out, if it's puffing smoke out of the dipstick tube you need to address the PCV before the excess crankcase pressure blows an engine seal - Mike

[merc85]

sounds like Turbo return seal, nice easy fix

[TenaciousC]

Take the top cover off the engine (the black plastic part) and have a look if there is oil under that, did you spill any oil when you last topped it up/ changed the oil, double check the condition of the filler cap seal as these tend to harden then they leak. Finally check the PCV, with the engine up to temperature and running pop the dipstick out, if it's puffing smoke out of the dipstick tube you need to address the PCV before the excess crankcase pressure blows an engine seal - Mike

Hi Mike,

Thanks for the reply. I forgot to mention in my original post that the PCV system checked out OK i.e. no smoking dipstick and also no inflation of a rubber glove held around the the filler neck whilst revving engine.

I did note that after the oil change, that oil had come out of the filler cap and was sitting under the black pastic cover (but I cleaned that up a few weeks ago and there was less evidence of this happening recently). I suspect the seal is ropey as it feels quite hard. It was an ebay one I purchased last year.

Even with the leaking cap, I can't see how the oil could easily get to where it is accumulating (at the back under the exhaust manifold) without leaving an obvious trail across the top of the engine.

[TenaciousC]

sounds like Turbo return seal, nice easy fix

The turbo oil feeds look to be OK. The oil on the turbo seems to be more on the compressor side... it could be top oil feed pipe, but I don't think that one typically leaks (as it's a banjo fitting with copper washers)

There is a good distance between the turbo and the cylinder 1 manifold, so I think they must be separate leaks.

[stribo]

Have you had a look to see if it's leaking out from the cam cover gasket?

[TenaciousC]

This thread is interesting.

http://www.volvoforums.org.uk/showthread.php?t=50802

Post #7 describes a very similar problem and mentions some kind of "in head" filters which could get blocked and be easily unblocked in under an hour. Has any one else heard of such things? News to me!

C

[T5frankie]

i too have a nice leak and burning smell lol

[bongodave]

Rocker cover gasket. Did it have synthetic oil in before? Did you spill any? Clean crank-case and rocker breathers with rocker cover removed, poke wire down any oil feed/breather pipes, clean breathers and hylomar rocker cover back on.

[TenaciousC]

Rocker cover gasket. Did it have synthetic oil in before? Did you spill any? Clean crank-case and rocker breathers with rocker cover removed, poke wire down any oil feed/breather pipes, clean breathers and hylomar rocker cover back on.

Yes always use synthetic oil. Not spilt.

Removing rocker/cam cover not trivial. Also no sign of leakage at the back of the engine along the cam cover/head gasket line. It's all very mysterious.

[bongodave]

Only takes a very light seep fro cam cover onto exhaust manifold. Seen it may times and it always due to blocked breathers causing oil to force out of gasket due to excess pressure.

[TenaciousC]

Sure thing, but PCV appears to be OK so if there is an oil pressure build up occurring in the top of the crankcase then something else must be causing it.. ALSO main buildup of leaked oil appears to be below manifold on rear coolant feed at back of engine. How it is getting there ££££ knows!

[bongodave]

Can't understand how you smelling burning oil if it is below exhaust manifold.

[stribo]

Sure thing, but PCV appears to be OK so if there is an oil pressure build up occurring in the top of the crankcase then something else must be causing it.. ALSO main buildup of leaked oil appears to be below manifold on rear coolant feed at back of engine. How it is getting there ££££ knows!

Mine had oil down the back of the block, it turned out to be the rear camshaft oil seal.

[T5frankie]

Can't understand how you smelling burning oil if it is below exhaust manifold.

it gets blown back by the wind, i had oil all over my back window from a leak down the front of my engine

[bongodave]

it gets blown back by the wind, i had oil all over my back window from a leak down the front of my engine

Lol. Use less vegetable oil in the screenwash!

[TenaciousC]

Mine had oil down the back of the block, it turned out to be the rear camshaft oil seal.

Cheers I'll look into that.

C

[TenaciousC]

Hello everyone,

This leak is still ongoing. It never drops onto the drive. I changed the Oil seal on cam sensor cam as there was a small leak.... but as I mentioned before I believe the main source to be coming from the cylinder 1 exhaust manifold.

The question is how?

Above the manifold... the cylinder head join (between upper and lower sections) is completely dry.

So the source could only be from within the cylinder head.... My theory is that the turbo is on the way out and oil is being forced into the engine combustion chambers and is going into the exhaust system, and finding a way out of the manifold on that cylinder. However, one would expect to see lots of blue smoke when under boost, and there doesn't appear to be any. Oil consumption is far higher than normal - so it's got to going somewhere, but it's not dripping out so it's got to be being burnt.

Thoughts and opinions please!! :-)

Cheers

C

[stribo]

Did you check the turbo oil return seal, as when this goes, it fires oil up the back of the engine under boost, so although the oil may look like it's coming from that bolt, it may have been sprayed from beneath. The problem is, when the car's idling it doesn't leak, so you can't just get underneath the car and see where the oils coming from, it has to be on boost before it sprays it out. If it was leaking past that stud, the nut would have to loose to allow it to escape.

[TenaciousC]

Did you check the turbo oil return seal, as when this goes, it fires oil up the back of the engine under boost, so although the oil may look like it's coming from that bolt, it may have been sprayed from beneath. The problem is, when the car's idling it doesn't leak, so you can't just get underneath the car and see where the oils coming from, it has to be on boost before it sprays it out. If it was leaking past that stud, the nut would have to loose to allow it to escape.

Hi, yes the turbo oil return seal was recently changed (for the reason you describe.) Didn't appear to make any difference. I thoroughly checked it and there is no oil on the back of the block, it seems to dripping down from above.

C