Boost leak loud squeal more prevalent when cold

[bpull]

I am looking for a boost leak that doesn't squeal all the Time . When truck is cold I can get it to squeal and goes away when I lift, after it warms up it may not do it. I have psi tested to 20# which it will not hold. I can hear air under valve cover and when I remove oil cap It is louder. I soap all boot connections. Do not hear air any other places. Should the psi hold when checking. My mechanic told me that you can not psi test because the valves will be open and blow right out exhaust. Any suggestions?

 

[bpull]

Sorry forgot to add 2003 5.9 355000 miles stock

 

[6speed]

Yes valves will be open, but my son and I did his turbo equipped Honda trying to find some air leaks and yes it will pressurize, but it won't hold pressure very long. I had it up to about 15 PSI and like I said it fell off quickly. I just made sure I didn't excede about 25 PSI while doing it.

 

[SierraRam]

Are you sure it is not on the exhaust side like the turbo mounting flange?

 

[leaky gasket]

Do you think it could be possible that you have a crack or a delamination in your charge air cooler? Your scenario reminds me of an exhaust manifold that ticks when it's cold but seals when it's hot.

 

[bpull]

If it is the exhaust side will I find soot build up at suspected area? If it is charge air cooler cracked or delaminating wouldn't it leak and make noise all the time. Drove truck 120 miles today 25 degrees truck plugged in did not make noise once.

 

[6speed]

If it is in the exhaust side I would think you would find some soot build up. I'd try the pressurizing route first. It took both of us to chase it. One putting air in and the other running their hands around all the joints. I had a little problem keeping the adapter on when I was putting air in.

 

[Joseph Donnelly]

To get it to hold 20 psi you have to cap off the lines at the engine and at the turbo. Also check the turbo to make sure the bushings are good and the impeller isn't rubbing on the housing during spool up.

 

[Bob4x4]

You do not need it sealed to find a leak if you have a compressor.Regulate to the pressure your test rig is safe to(30psi or less).Spray a soapy solution on all the possible leak sites.It will bubble up.

 

[buzzinghalfdozen24]

I agree with Joe. I'm a heavy equipment technician, and have had several squalling like crazy. I go on troubleshooting boost, rail pressure, starting, etc... then 20 minutes later the turbo seals blow out sending an oil cloud out of the exhaust.