I can't find boost leak

[dsmcoder]

I can hear a whistle of air in my car when under boost, it just started doing this. I tried to do a boost leak test but I can't find out where the leak is coming from but the pressure only holds for about 10-30 seconds before all the air is out. It sounds like the air is coming from inside my engine and I can feel some air coming from my dipstick, is this normal? What possible reasons would cause air to be leaking in my engine?

 

[mx035racer]

Try spraying soapy water on everything when you do the boost leak test, that way whatever is leaking will blow bubbles thus making the boost leak test more efficient. As for the air coming from the dipstick tube that is normal. You can always do a compression test just to make sure your rings arent worn plus its always good to know your compression numbers.

 

[dsmcoder]

I did a compression test last week, I had 150 across the board.

 

[nrwtrn6492]

150 is very good

Just as stated before you need to use windex or soapy water on every coupler and anything connecting your turbo to your intake manifold.

What PSI are you able to hit while doing a boost leak test.

 

[mx035racer]

Then you should be all set! As long as the leak isnt excessive then it is normal for 1g 6 bolts to leak boost out of the dipstick. I know a few people who actually bought a dipstick from STM so the dipstick wouldnt pop out. Also check to see if your pcv valve is working properly.

 

[dsmcoder]

I went up to about 20 psi, I don't have a problem getting the pressure up there, but as soon as I remove the air source it doesn't hold it.

How do I check the pcv valve? There has to be something wrong because it wasn't making a hissing sound before under boost while driving.

 

[Calan]

You also need to make sure that the engine is warmed up and the valves are all closed. If the engine is cold and any intake valves are open, air can leak past the rings and into the crankcase. Warm the motor up and then manually rotate the motor so that it is 10-15* past TDC before doing the BLT.

From this article:

How do I test my PCV valve?

The PCV valve should allow air to pass through in one direction but not the other, and the internal spring and ball should move freely (if you shake it, you should be able to hear it rattle). To check it's ability to seal under boost, apply about 5 psi more than the amount of boost you plan to run to the hose nipple, opposite the threaded end. There should not be any air escaping from the threaded end.

 

[dsmcoder]

I ordered some of those check valves to put in, hopefully it solves the problem.

 

[cbr600teardrop]

tb shaft seal leak extremepsi.com has the seals

 

[Jafro]

If it leaks down fast and soapy water didn't show you anything on any part of the intake, plug up and clamp your breather hoses using bolts and zip ties. That will shut 'em up for the test and help you find other leaks more easily. Tie down the dipstick to keep it from launching if you do this. See if you get the same result.

If so, it's probably your turbo's center section. Remember that thing is connected to your oil system and crankcase. Blow-by won't have anywhere to go if you plug the breathers, except out the exhaust if the center section is leaking. Mitsubishi turbos are famous for this because of their 270° bearing design. It's why Mitsubhishi turbos get smokey when they're old. Listen to the exhaust. I like to just stretch a rubber glove over it and watch it.

But if blocking off the breathers slows down the leak enough and verifiably on the boost gauge that it takes twice as long to leak down, then it's leaking into the crankcase rather than the exhaust. If the air stops completely, you don't have a leaky center section, you have a blow-by problem.

...but that's the complicated part. It's usually the easy stuff.

If you haven't done the soapy water thing, use Softsoap. Get an empty windex bottle and add about 10 squirts to 2/3 of a bottle of water. Best bubbles for this kind of thing and the smell attracts petite twenty-somethings for some odd reason.

http://www.youtube.com/watch?v=fdjadhUP1u4