Boost leak check

[civic619]

Hey guys,

I just performed a boost leak test on my car... When I pressurized it, I heard bubbles come from the oil pan. I am also unable to bring the boost levels past 5psi. Could I have lkea in the turbo where the air is escaping on the oil return line?

 

[DSMWillyb]

Some bubbling is normal... Why can't you pressurize it more than 5psi?? Are you using a hand pump or a compressor??

 

[steve]

I disagree. I can hold 20 psi without any oil bubbling sounds. Check your PVC valve to see if it's leaking under pressure. Use soapy water to look for other leaks.

Steve

 

[civic619]

this was done with an air compressor. I will check the pvc. Thanks.

 

[LowFourteen95]

I had a 14b that would allow the same noise to occur. When I upgraded to my EVO III 16g, the bubbling stopped. So my experience tells me that it's exactly what you originally thought.

 

[steve]

Good Point, I forgot last night that air can leak from the compressor to center section and into the oil lines. Normally you would have some oil pressure in the center section that you don't have when leak testing to help seal the shaft but it's not a good sign if a lot of air leaks past.

One way to narrow down where the leaks are is to test parts of the system starting at the manifold and working back to the compressor inlet. Cap the intake to the throttle body and use the PVC line to pressurize the manifold. Fix any leaks found and then move downstream and repeat.

Keep in mind that there is a small random chance that when you stop your engine it will rest in a position where a cyl has both valves open (valve overlap at the end of exhaust stroke and beginning of intake stroke) and air will go right out the exhaust.
Setting the crank to at least 30 degrees before or after TDC should make sure there is no more than one valve open per cyl.

Steve