Compression and/or Leak Down Tester

[Shawn]

Anyone have a compression tester that Chris and I can borrow to test the engine on the TT? We had a small oil leak that we have identified at the valve cover gasket but we are seeing some more oil at the back of the engine that might be from the head gasket. I suspect we really need the leak down tester as I suspect a compression tester would not show a small leak in the head gasket.

Shawn

[MRS Joe]

Oil from the head gasket leak wouldn’t present with a compression tester unless the leak was from oil passage to the combustion chamber. 

Since it’s visible it’s external which is a pain.

Usually it’s the high pressure oil passage that runs up the side of the block (many motors) into the head that leaks between the passage and external world. It’s a leak that is dreadful but not that common. I’d check seals and other sources as testing this is impossible. I’d thoroughly clean the area and use dye and a UV light to trace it.

Did you put in a high volume oil pump or shim/regear the stock one? 

I have a compression tester your welcome to borrow 

[Shawn]

Thanks Joe. Chris did notice that when he was driving there was some smoke occasionally. He thought that the smoke was white but it could have been bluish...hard to tell though the mirrors while driving, but not black. What you say makes sense about the oil pump as the one leak that appears to be between the head and block is on the same side as the oil pump (which is completely stock).

Chris thought that maybe the catch can got too full which might have been a cause of the smoke but running a few tests wouldn't hurt either.

I am grabbing a leak down tester from Corey today and might hit you up for the compression tester too.

[Brian_Earl_Spilner]

If it was white smoke, blown head gasket would be a suspect for sure. Have one of you trail behind while the other blasts it in front to confirm.

Edited July 10, 2018 by Brian_Earl_Spilner

[Shawn]

Yeah, Chris confirmed today that after fixing the one leak on the valve cover gasket and going for a drive, that when he shifts gears he gets white smoke and says he can smell the coolant. But he says it only happens when he shifts...so far. Driving behind to really see what is happening is a good idea.

[MRS Joe]

There’s vacuum/negative pressure in the cylinder when lifting out to shift. It’s probably pulling the coolant in then.

You will probably be getting bubbles in the coolant under load. 

[Shawn]

1 minute ago, MRS Joe said:

There’s vacuum/negative pressure in the cylinder when lifting out to shift. It’s probably pulling the coolant in then.

You will probably be getting bubbles in the coolant under load. 

Besides gasket failure or crack in the block/head, what else could be the cause?

[MRS Joe]

Well the gaskets on the oil filter housing are notorious on the BMW’s. But that would show as milky oil and/or discolored coolant only.

I think your looking at a head gasket. A compression and leakdown test can tell for sure.