Help diagnosing/confirming a possible boost leak

[07specbshtbox]

I've been hunting down a new noise that developed that sounds like a BOV, except I have a factory BPV installed so there should not be any such noise. After tracing vacuum lines and looking at mating surfaces for evidence of a leak I remembered the issue with the OEM intercoolers and how the end tanks separate from the core. I inspected the intercooler and found one side that looks to be separating just the tiniest bit and bending back the tabs that clamp it down.

 

Every other side has the tabs seated flat against the plastic, is this the source of the noise?

I would also like to know if its possible to pinch the tabs back down and buy the Bulletproof TMIC kit or if I should track down a junkyard intercooler that isn't separated then bulletproof that one instead. Any input is appreciated.

[tdelker]

I believe the most common cause of that noise is the large hose between the intercooler and the intake have a small gap in it and at high boost it causes a noise. Might want to look there and refit and retighten that interface.

[silverton]

there's definitely an issue with your intercooler. You can try squeezing that back down and see if it takes care of your issue.

[m sprank]

That could be or could not be an issue.  It might be the very beginning of the seam separating at that single point, or not.  I HIGHLY doubt that is the source of any noise.  A smoke test is your friend.  Otherwise, keep looking. 

[07specbshtbox]

I would try a smoke test but I'm pretty confident that it would pass even with the intercooler being the issue. I don't hear any noise like an air leak at idle, only when under boost. I don't think a smoke machine could pressurize the intake system to boost pressures.

[m sprank]

Mine hit 14+ psi.  Yes, thee are smoke machines that specifically operate at higher pressures.  Turbo shops use them to replicate boost.  Many shops use these to locate vacuum leaks and emission module leaks working from the exhaust back to the engine. 

[07specbshtbox]

I will have to call around to some shops and see if they're willing to do a simple smoke test for cheap or free, I can't afford to do much more than that rn.

[m sprank]

I charged a flat rate of $40 for a smoke test on a turbo Subie.   Today I would probably ask for $50-$75 (inflation). 

[tdelker]

There are smoke machines on amazon for $100. I plan on doing this as if I find something, I need to probably get a gasket, then retest. Pretty soon you are over the cost of the machine. If you want the shop to do the work, probably easier to just let them find AND fix the leaks.

For full pressure, I am going to try to build something that attaches do the turbo (I have a gen 5 GT so front mounting makes this easier) and pressurize to 14 psi and look for a leak slower than 1 psi/sec. If its higher, try to listen to find it and plug it.

To be fair, I've never done either, but I also had never pulled an engine or installed a head until a few weeks ago, and that went well! 

[m sprank]

A professional smoke machine capable of 14+ psi will cost over $3000.  They are not available on Amazon.  REAL tool cost REAL money.  Thats why mechanics charge $100+ per hour.  They have to pay for the tools purchased on credit.   Tools are like a loan that never goes away because you always need new/replacement tools.  The software updates on a professional scanner cost several thousand dollars per year alone. 

 

I closed my shop in 2018 and paid off my tool bill with Snap On April 2022. 

[tdelker]

Totally! I'm not suggesting do it with the $100 smoke machine and a separate home-made pressure test is going to give the same ease of results and I understand shop rates have a lot wrapped up it in. I don't begrudge it at all. A good shop is worth the money!

[Max Capacity]

What I do for the boost leak test is, plug the tube coming off the air filter box. Take the small hose off the BOV, give that hose a "quick" blast of air from my air compressor, put my thumb over the hose, listen for leaks. That seems to have worked well for me over the years.