How would you know when to replace valve oil seals
 

So i know this is completely the wrong forum but i have a 98 passat v6 stock turbo in my garage and its burning oil. Either, bad turbo, pistons rings, valve seals, But how can figure out which it is. I would put this on a VW forum but this is not a car specific. it could go with any engine.

Thanx.

well when i blew my turbo on one of my dsm's i could floor it and get on boost and there wouldnt be any smoke. then as soon as i let off, tons of smoke. thats how i knew it was my turbo. another way to find out would be to pull the exhaust manifold and see if its covered with oil. if the manifold before the turbo and closer to the head isnt covered with oil and the exhaust housing after the turbo is covered with oil, you'll know where your problem resides.

ya, turbo, im familiar with seeing the condition. My question was more towards, how would i know if the valve seals need to be replaced. Thanx for the answer.

I would do a leakdown test first.

How many miles are on that engine?

oh gotcha. sorry. i thought i read that your original post asked how to figure out which is the problem.

do a leakdown and go from there.

Blowing Smoke
 

1+ or more!! Yep, easy test not requiring much in it way of wrenching. :thumbup:

I can understand leakdown helping with combustion chamber leaks. So if its not combustion chamber leak or turbo, then it must be seals right? Is that what you are saying.

bring it to sears! LOL.. sorry Ed I had too.

hahaha, I'll take it there when my gun cant take off the camshaft cap bolts. ;)

a leakdown test won't show if the valve seals are going bad. it'll show if you have a bad fitement between the valve and the valve seat.


if your valve stem seals are done, there will be oil leaking down the valveguides.

I know this, which is why I asked mileage. Leaky valve stem seals usually result in blow by through the intake manifold via PCV, and could be a source of oil consumption. But the first thing I would check, if I have a high oil consumption motor, is check leakdown first...then work from there.

I can also take the intake manifold off and check on the intake valves to see if its oil covered right? That way, it would be seals?

One sign for leaky stems is the spark plug tip would be covered in oil.

leakdown is also a good place to start

If it blows a good amount of blue smoke when you start it, that's a sign of the valve stem seals leaking. As when you turn off the motor, oil will leak past and down the valves/combustion chamber. When you start it, it will burn it off and then not smoke until you let it sit again.

Turbo oil leak. Just pull off hose just forward of the turbo's compressor side. If it's all oily, there you go.

Rings, you'll see oil when driving and especially in boost. As said, a leakdown test would verify

Thanx jeff.

Ok so i took off the intercooler pipe today right before the intercooler and i saw maybe a glass full of oil just pour out. I was shocked how much oil came out. So i guess the turbo needs to be replaced.