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Hello! need some advice. I have oil drips on the front exhaust pipe. It looks like it's coming from between the engine and gearbox. Dont think it's main seal because the underside of the bellhousing is not dripping. I will attach some pics maybe someone looks at them. Thnx.
Photo0011.jpg Photo0014.jpg Photo0021.jpg Photo0013.jpg
 

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The rear main crank seal is a very common leak source. Pretty much 100% guaranteed to leak as the miles grow TBH.

That first picture showing the drips on the sump tends to suggest it's that one, but oil drips do tend to move about a bit. The rear face of the flywheel is almost in the same plane as the joint between crankcase and bell housing, so you'd not expect to see oil dripping from the bell housing - the flywheel tends to keep it on the engine side. I see the small cover plate at the bottom has been removed in that second picture, that can trap a bit of oil if present. If absent, there's really very little that can make the oil from a leaky crank seal get into the bell housing.

Other common sources of oil round there would be either the gearbox input shaft seal or possibly the first signs of a failing diff. What can happen there is the diff pin comes loose, starts to shift out of place and grinds a hole in the casing inside the bell housing. Both these leaks will get you gearbox oil rather than engine oil of course, and you can probably tell the difference from the smell.

Not seen an engine oil leak on the back of any V6 that wasn't the rear crank main seal though.
 

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The rear main crank seal is a very common leak source. Pretty much 100% guaranteed to leak as the miles grow TBH.

That first picture showing the drips on the sump tends to suggest it's that one, but oil drips do tend to move about a bit. The rear face of the flywheel is almost in the same plane as the joint between crankcase and bell housing, so you'd not expect to see oil dripping from the bell housing - the flywheel tends to keep it on the engine side. I see the small cover plate at the bottom has been removed in that second picture, that can trap a bit of oil if present. If absent, there's really very little that can make the oil from a leaky crank seal get into the bell housing.

Other common sources of oil round there would be either the gearbox input shaft seal or possibly the first signs of a failing diff. What can happen there is the diff pin comes loose, starts to shift out of place and grinds a hole in the casing inside the bell housing. Both these leaks will get you gearbox oil rather than engine oil of course, and you can probably tell the difference from the smell.

Not seen an engine oil leak on the back of any V6 that wasn't the rear crank main seal though.
Ok. thanks for the info but i still dont think that it's a crank seal. Shouldn't the inner side of the flywheel have oil on it? Because it has absolutely zero oil on it. The car only has 52000kms and i removed that small plate just to take the pics. The oil is definitely engine oil.
 

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You won't necessarily get oil on the back of the flywheel - it comes out between seal and crank (obviously!), and drips down from there. Rotation will tend to throw it out rather than it travel horizontally along the bottom edge of the boss the flywheel bolts to. Quite often the bottom of the seal can be pretty wet and the top totally dry - it's just the way it goes.

Very rarely, you can get a leak between the rear main bearing cap and the block if the sealant wasn't correctly applied when the engine was assembled.

Could in theory have a head gasket leak back there I suppose, but you'd see that on the outside quite obviously and I doubt it would make its way down to the sump before you spotted it all over the top of the bell housing.

Oil gallery plug at the back near the top....maybe

Leak from the sump/block join at the back, also maybe.

I've tried to find a good picture that shows the back of the engine but there's nothing great. Have a quick Google and see if you can find something, but you'll see that the only place oil can come from inside the engine and get where it's getting is rear main seal or oil gallery plugs.

Pretty sure you're going to have to pull the box & flywheel to find it, and when you do, pretty sure it'll be the rear main seal.

Once you have the flywheel off, replacing the seal is easy enough, no need to remove sump or rear main cap.

I should say, I don’t want it to be the rear crank seal, it’s just the most likely cause of the problem.
 

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You won't necessarily get oil on the back of the flywheel - it comes out between seal and crank (obviously!), and drips down from there. Rotation will tend to throw it out rather than it travel horizontally along the bottom edge of the boss the flywheel bolts to. Quite often the bottom of the seal can be pretty wet and the top totally dry - it's just the way it goes.

Very rarely, you can get a leak between the rear main bearing cap and the block if the sealant wasn't correctly applied when the engine was assembled.

Could in theory have a head gasket leak back there I suppose, but you'd see that on the outside quite obviously and I doubt it would make its way down to the sump before you spotted it all over the top of the bell housing.

Oil gallery plug at the back near the top....maybe

Leak from the sump/block join at the back, also maybe.

I've tried to find a good picture that shows the back of the engine but there's nothing great. Have a quick Google and see if you can find something, but you'll see that the only place oil can come from inside the engine and get where it's getting is rear main seal or oil gallery plugs.

Pretty sure you're going to have to pull the box & flywheel to find it, and when you do, pretty sure it'll be the rear main seal.

Once you have the flywheel off, replacing the seal is easy enough, no need to remove sump or rear main cap.

I should say, I don’t want it to be the rear crank seal, it’s just the most likely cause of the problem.
Thanx a lot! I've done some research myself and found the same. maybe the cigarette seals but not convinced. Anyhow thank you for helping.
 

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Alfa stopped using actual rubber cigarette seals many years ago and moved over to just squirting silicone sealant into the holes on assembly. TBH, works better than the original idea and a whole lot easier to do.

Probably about the same time they stopped using sump gaskets and went over to liquid sealant for those too I think. Mid-late '90's I reckon.

166 for sure is a gob-of-snot job :)
 
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