Hi i'm having trouble with some very annoying oil leak from tha back of the engine (Miata 1.6 '91). To cut the story short every sealant was replaced with new one (cas, valve cover, under flywheel) and the gearbox bellhouse is still covered in oil, especially on the top.
Here's a picture with droped gearbox:



As you can see cas is clean. Oil covers the area from collant route all the way down. Any sugestions? Could it be blown head gasket?

 

is it your turbo's oil feed fitting? very hard to tell form the pic, but might be headgasket.

 

Well the oil feed line was replaced two monts ago - original greddy line just droped dead. No leak from this point. Dry and clean.
Is there some kind of way to tell is it headgasket for 100% ? There's no oil in coolant and water in oil. Car runs perfect except it drops little oil on the ground.

 

did you just pound a new rear main seal in? or did you take off the bracket that holds the rear main seal. if you didn't, that could be leaking. along with the little half circle rubber pieces, there's one on either end of the oil pan

 

Rear seal sits corectly. Rear cover was tremoved in order to replace the oil seal. All done by the book.The flywheel is dry and clean from the seal side.The oil drops from way above. I have no clue...

 

Can't you get a glow in the dark dye that you add to the oil? That should help you pin point where it is coming from.

 

I just used a UV dye for the cooling system. It did end up helping me trace my leak.

 

might be a dumb idea.... but check the rubber boots on your shifter.... my inner was torn, and I overfilled the turret, it covered the top of my tranny in what looked like oil but was not. It freaked me out until I figured out what was goin on!

 

Is UV dye for coolant/ac mixable with engine oil?

Those rubber boots are brand new... besides it is engine oil that drops on the ground

 

Did you remember to put sealant on the corners when you replaced the valve cover gasket?

 

Yes, I've paid a lot of attention to those 90 degree corners. Sealed with a high temp silicone.

 

The bronze colored freeze plug looking thing to the right there is for the oil galley. Since there's oil inside of your starter, this could be leaking.

 

I believe there is specific UV dye for oil system. I picked mine up from the local autozone. Total cost was like 20 bucks for the dye and a glasses/blacklight pen kit.

 

This does sound an awful lot like the oil leak I was having earlier in the year. Mine did in fact turn out to be the head gasket. It was depositing oil on the top of the bellhousing which worked its way back to coat the whole tranny, and a small amount of it even managed to climb up to the top of the valve cover near the ignition coils.

 

Sounds like I have the same thing. Tomorrow I will try to clean this mess and seal everything once again this time with a lot of silicone, put it back together,go for a ride and try to spot that leak. Before I will dissamble the engine i would like to know it its head gasket for sure.

 

Problem solved. This leak came from bridge over CAS (this bridge holds CAS from above and its screwed to head with two bolts). I took it off, put silicone betwen head and bridge, put in cas, bridge and bolted them together.
Not even one oil drop since then....