Turbo seals leakage

[blackrosenova40]

Basically I did a boost leak test and I heard air whooshing ino my exhaust manilfold.
So I decided to do a test after the turbo compressor and had no leaks so that ruled out valve overlapping.


My question is this, is it supposed to leak without there bieng oil pressure? I have heard that it may and I have heard it shouldnt so I dont know what is the correct answer.

And if the turbo is not supposed to leak , even when there is no oil pressure, is there any way I can replace the seals on the compressor side myself, and what seals are there.

 

[blackrosenova40]

psshhhhhhhhhhhhh

 

[ericbev]

It is normal for air to escape around the bearing during a boost leak (at the inlet versus the intercooler pipe) test because of the lack of oil pressure. You were correct.

On a side note, dont bump your own threads, its against the rules.

 

[blackrosenova40]

Well Ive heard that it is normal, and I have heard that it isnt normal.

 

[blackrosenova40]

So for everyone that does a boost leak test, it will result in air leaking into the exhaust manifold from the turbo? Whats the point of doing the boost leak test at the turbo inlet then? WTF

 

[chanley talon]

I usally do my boost leak test on the nipple of the j pipe . I block off the the j pipe with a piece of metal that i drilled holes through and bolt it down using it as A block off plate .
My car sounds like yours a leak somwhere in the motor? However my brother in laws will hold boost great during the test matter fact when his gets to 18 19 psi the motor starts to roll over! His slowly loses boost!

 

[blackrosenova40]

What im saying is that if it were true that the turbo is supposed to leak into the exhaust manifold without oil pressure, then why are people making boost leak testers at the inlet at the turbo.

My car does leak air into the exhaust manifold during the boost leak test but none if I do the test after the compressor.

 

[oldman]

No, it isn't normal for compressed air to go from cold side to hot side during a static test, it is normal however to leak from the cold side -> oil return -> crankcase. Are you blowing smoke under boost? Air escaping into the exhast, verified by listening at the tailpipe and not mistaken with the sound of conpressor cover seal leak, are usually caused by valve overlap or stuck open EGR.

 

[blackrosenova40]

As I stated I have no boost leaks after the compressor, but I do hear what sounds like air going ino my exhaust manifold if I do a boost leak test at the turbo inlet.

On a side note, why dont they make some kind of colored gas that would be safe in the intake tract, that we could somehow use to compress and watch it escape where our boost leaks are?

 

[kenamond]

As I stated I have no boost leaks after the compressor, but I do hear what sounds like air going ino my exhaust manifold if I do a boost leak test at the turbo inlet.

On a side note, why dont they make some kind of colored gas that would be safe in the intake tract, that we could somehow use to compress and watch it escape where our boost leaks are?

As oldman asked, do you see blue-white smoke under full boost? Have you checked the turbo for in-out or excessive side-side shaft play?

If the seal is blown, you'll be burning a lot of oil. Having a minor amount of air leaking into the center section is normal, but I usually hear bubbling where the oil return tube bolts to the oil pan, but it's like maybe two "bloop"s per second. If a huge amount of air were being pushed through the oil return tube, this would blow up into the valve cover and out the VC breather, not the exhaust manifold. The only way I can think air could get to ex. mani. when pressurizing at the compressor but NOT leaking there after the compressor would be if you were leaking straight into the turbine housing, but you'd be burning oil then, too.

 

[blackrosenova40]

nope no smoke whatsover and the turbo has 0 shaft play (stock 14b)