boost leak test

[datbmac]

When doing a blt are there supposed to be any air leak through the turbo? I have replaced both o-rings inside of the turbo.

 

[Brandon1ggsx]

There should be zero air leaks.

 

[TSITurbo95]

^ Perfectly said. No leaks at all.

 

[datbmac]

Ok will a complete turbo rebuild stop that leak?

 

[Best Talon TSi]

A full rebuild should stop the leak. But yeah there she be no leaks at all.

 

[Brandon1ggsx]

Did you spray it with soapy water to determine 100% where its coming from??

 

[habitatguy187]

Who knows, the housing might be cracked somewhere and you just need a new turbo. How bad is it leaking out?

 

[datbmac]

I used a smoke machine on monday and found out the compressor seal was leaking so I replaced that and I did another boost leak yesterday and heard it leaking through the housing on the hot side so I thought maybe if I replaced the other o-ring the leak would stop. So then I ran another boost leak test today and it was still leaking but not as fast as it was before. I was going to have it smoke tested again on monday or tuesday but I was just gathering information before I go on.

 

[habitatguy187]

How slow is it leaking out? Like if you pressurize it to 20psi how long does it take to bleed down to 10, from 10 to 5, from 5 to zero? All cars will slowly leak boost. Was the car warmed up? It's POSSIBLE that the oil seal needs heated up to create a good seal, but I wouldn't hold your breath on that one.

 

[JayB12]

Is your engine rotated so your intake valves are shut while testing? If not you could just be leaking out the exhaust valves. Which could explain the change in flow between tests as well.

 

[datbmac]

How slow is it leaking out? Like if you pressurize it to 20psi how long does it take to bleed down to 10, from 10 to 5, from 5 to zero? All cars will slowly leak boost. Was the car warmed up? It's POSSIBLE that the oil seal needs heated up to create a good seal, but I wouldn't hold your breath on that one.

The highest it got up to was 17 psi and it dropped down to 10 in about 2 seconds, down to 5 in about 2 more seconds, and down to 0 in about 5 seconds; and the car was cold when I did the tests.

Is your engine rotated so your intake valves are shut while testing? If not you could just be leaking out the exhaust valves. Which could explain the change in flow between tests as well.

I haven't started the car since the first test I did on monday. Plus I have the exhaust off the car and I don't hear any air coming out of the exhaust ports.

 

[edged1g]

Is your engine rotated so your intake valves are shut while testing? If not you could just be leaking out the exhaust valves. Which could explain the change in flow between tests as well.

Not to hijack the thread, but I have been searching EVERYWHERE to find out exactly how to do this, and have come up empty. I read i want the crank at 51* ABDC but HOW do i actually get the engine to that state? any help is appreaciated!

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[datbmac]

Not to hijack the thread, but I have been searching EVERYWHERE to find out exactly how to do this, and have come up empty. I read i want the crank at 51* ABDC but HOW do i actually get the engine to that state? any help is appreaciated!

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The easiest way would probably be to take the valve cover off and rotate the crankshaft until you see the intake valves physically close. That would get you as close as you need.

 

[datbmac]

I found the leak today. I used a smoke machine with the turbo off the car and saw smoke coming out of the oil drain. So I guess it's time for a rebuild.