bubbly noises pressure testing charge pipes
 

so today was boost leak eradication day. had 3 boosted 86's in the green monsta's garage all getting tested. all three made this weird bubbly gurgly noise when the system was pressurized... sounded like fluid bubbling. any idea what this might be? tried popping the oil cap and gas cap to see if pressure was getting in the fuel system or crankcase... nothin'. ideas? anyone else pressure tested their system and heard the same thing?

http://miketurboinc.com/pages.php?pageid=16

Dont know if this helps, but good luck with finding your problem!

I will let you know in a few days.

i check coolant also, gotta be fuel.

I had some gurgling noises after having the car sit for three months. It was coming form the catch can. Was worried I somehow f*cked up the motor.... It went away after a few WOT pulls. I figured it was the PCV valve clogged up.

I have not heard them ever again.

Probably off topic but just a random thought to consider.

Was this when the cars were on or when the engines were shut off, had something similar on my wrx when I turn the car off. I flushed the radiator and changed the thermostat and the noise went away.

Where do you have the caps when your pressure testing? I always put mine at the turbo inlet and then at the pipe the hooks up to the TB. So when I pressurize it's only the turbo/pipes/and intercooler. I don't see how any of that would reflect in the motor? Is that how you did yours?

@jamesm did you find out what the bubbling was from?

Yes that is how we were testing, at the turbo inlet. I still haven't thought of anything that could be the cause. I don't think it's a problem as much as just some weirdness lol. All 3 cars made the same noise, and none had abnormal leakdown.

I'm definitely interested to find out what it is though, for science.

Edit: just re-read your post and no we didn't block off the pipe at the throttle body, just hooked up to the turbo inlet and expected some leakdown through the valves. We didn't rotate the engine to tdc first either.

I wont be able to test mine until the weekend. I will have an update by then though.

This, otherwise your pressurizing the head, the block, the pcv system, etc the gurgling sound is probably air bubling through oil.

In fact we are not pressurizing the oil there is no pressure at either side of te head. Also Im not running pcv in my setup neither are the other two cars.

You can in fact leave the TB elbow on and pressurize the entire intake system including the manifold which is where most leaks occur. You take that elbow off and cap it you wont know about any leaks after the TB. TB seals can leak, vacuum lines attached to the mani can leak.

The only thing capping the at the TB solves is ic piping and bov leaks. Which i would find hard to believe

I do my tests in 2 steps. IC/turbo/bov and then the manifold. Problem is you cant close all the valves but usually if you just keep the pressure going its enough to find any issues.

that's pretty much what we were doing.. just expecting some leakdown through the valves. it's easy enough to tell the difference between normal leakdown and a blown-off hose on the manifold (which seems to be the common culprit with these damn things).

and like @Ironsquid mentioned none of us have intact pcv recirculation. all dual VTA catch cans, as the turbo car gods intended :).