I see you already have posted it up.

Someone with a bit more experience with boost leak testing help this guy out. My suggestion was to do a leakdown test.

 

If you ran more than 20psi in your test, you probably pushed air through your rings.

Edit: When I do my tests, I rarely use more than 3-4psi of air. With the car off, you can hear air leaks very distinctly, and that's more than enough air to make soapy water bubble.

 

My boost gauge only read 5 lbs, 10lbs once when i pumped for a while.I thought you were supposed to put as much pressure as you plan on running, like15-20 psi to make sure it wont leak at peak boost?

 

Natch. I was fully spooling my turbo one night, but I was only developing 10lbs at the manifold. I put my pressure tester on it, instantly, I felt the wind come out of the charge pipe.

If you only had 5 lbs on it, and it was coming through the dipstick, chances are you got some blown rings.

Get a leakdown tester, rotate your engine until your cams have both sets of valves closed, and pressurize the cylinder, if you feel air moving through the dipstick hole, there's the guilty party.

 

If my rings were gone, wouldnt a compression test tell me this as well? Iether way i will know if my rings are bad, correct?

 

It would, yes. Which ever you have equipment for, do it.

 

Disconnect and plug the hose going from the valve cover into the PCV valve while testing. That's one of only 2 possible sources of air to get into the crank case. Only other way is through the valve stem seals/piston rings. TDC should close most, if not all the valves.

 

Ok will do. thanks for the help. So nobody thinks this could be bad turbo seals?

 

A compression test will tell you which cylinder is loosing pressure. A leak down test will narrow down the cause in that cylinder.

 

For enough air to travel down the oil return line, to make itself known, meh. It's much more likely for it to go through the easier paths.

 

More likely yes, But this motor has only 2700 miles on it, with everything brand new, and has not been revved past 4,000 rpm, which is why im doubting the rings, or valve stem seals. If it were the valve stem seals my motor would smoke due to oil leaking past them , and it hasnt the slightest hint of smoke. I will do the test just to confirm, because even new parts have been known to fail, I appreciate all of the help guys, keep the advice coming ^_^

 

The valve stem seals aren't designed to hold pressure. They're like a squeegie that scrapes the oil off the valve stem as it goes in and out. Put 20psi behind that seal and it won't hold a dimes worth.

Also, the piston ring breaking at 20psi is complete bullshit. There's even a special adapter designed to pressurize the cylinder chamber (80-90psi) so that you can replace the valve spings without the valves falling into the motor and eliminating the need to pull the head.

 

Check your turbo's compressor outlet for OIL. If you heard it gurgling from the depths of the motor when doing a boost leak test. Then you could very well be shoving air past the turbos seals. When mine did this, it also vomited a ridiculous amount of oil back OUT of the compressor housing and a half quart or more down into my fucking charge pipes...

(REAL fun the first time I opened the BOV and showered a cupful of oil into my engine at 30+psi) not...

I have not had the balls to do a leak test since. But I did purge all the oil from the system, and the turbo has not displayed any problems since.

A side note; if you really have 2700 miles on your "brandy" new engine and you haven't exceeded 4000 rpm I almost might blame the ring seal... it is possible, but not guaranteed that you have generated the correct loading to ensure proper break in and ring seal. I hope it saw 4000rpm at WOT and heavy deceleration in like 2nd gear... repeatedly...

If it is rings, a compression test would show it, adding a small quantity of oil will show an improvement most times if it truly is rings.

Although if the turbo is not new... I wouldn't doubt that you could possibly be pushing it up the oil feed line, or out of the drain tube.

As to the recommendation of only using 5psi to test a car. If you have a turbo doing what mine is, you may be forced to. But this is NOT THE WAY TO DO A BOOST LEAK TEST. So if you recommend doing it that half ass way again on a public forum where someone might just take your advice Need2fix, I will drive on down there and put my foot in your ass. There are sneaky leaks that only develop around or AT your desired boost level. Which means we test PAST our desired boost level to be SURE no leaks develop throughout our boosted range.

Period.

Everything's well and good until you shoot an IC pipe off at 30+psi and it comes off with enough force to shatter expensive things in your engine bay... while your driving... instead of in your garage...

 

As to the recommendation of only using 5psi to test a car. If you have a turbo doing what mine is, you may be forced to. But this is NOT THE WAY TO DO A BOOST LEAK TEST. So if you recommend doing it that half ass way again on a public forum where someone might just take your advice Need2fix, I will drive on down there and put my foot in your ass. There are sneaky leaks that only develop around or AT your desired boost level. Which means we test PAST our desired boost level to be SURE no leaks develop throughout our boosted range.

Period.

Everything's well and good until you shoot an IC pipe off at 30+psi and it comes off with enough force to shatter expensive things in your engine bay... while your driving... instead of in your garage...

Dude, more than 20- 25 psi in your engine block without it running WILL break your rings. Most of the boost leaks we have are retarded boost leaks from couplers, or pipes not tightened down right, and they will show up with barely any air moving at all. If you shoot a pipe off at 30+, and not at 20, generally something BROKE.

Meh, it's all about getting the job done without breaking shit (more).

 

Ahh so im not the first one this has happened to, ok thanks I'll do a compression test to see if my rings are good.

The motor is honestly brand new, and the only reason it hasnt been revved past 4k is due to fuel cut, and me not having DSMLink to tune with yet =/, this is also the reason it hasnt seen WOT.

As for the boost leak test, i planned on putting like 30 psi through the system, even tho im running 15psi at the moment, its more rational and also how would you know if your leaking boost at say 20 psi if you only put 5 psi through when testing? Just seems more logical to me.

 

As for the boost leak test, i planned on putting like 30 psi through the system, even tho im running 15psi at the moment, its more rational and also how would you know if your leaking boost at say 20 psi if you only put 5 psi through when testing? Just seems more logical to me.

The funny part is, I was dragging one night, and my turbo was spooling to hell and back, and I was only getting 20 psi through my system. I did a boost leak test, and as SOON as I put air through the system, I heard it creeping through my couplers. A half turn of the screw was the difference between 20 and 30 psi.

 

ok soo i did a compression test and its all good, rings are perfect, and so are valve stem seals. I did the boost leak test again with the PCV valve blocked off and the vacuum hose that runs to the wastegate also blocked off. It's still building pressure in the oil pan, so the only thing left is turbo seals, that i can think of.

 

You have to admit that there is a big difference in pressure between 20 psi and 30 psi, I just dont see how only putting 5 psi through the system will show you if 30 psi through the same system will leak or not. Im not saying you're wrong, I just cant come to a rational explanation as to how that would work, 5psi showing leaks that would occur at 30 psi. If you could explain i'd appreciate it.

Also as for the "20-25 psi would break you rings" comment, if that was true wouldnt a compression test fuck your motor up to hell, since it has like 150-250 psi of pressure in the cylinder without running, depending on the pistons, correct?

 

What you say makes sense in theory, but what doesn't make sense to me is how 30psi of air is going to bend a tiny lip of a piece of metal through the very small crack between piston and cylinder wall. I think of it as trying to break a full size pencil, then trying to break a pencil that's 1" long. Or holding the very edge of some sheet metal and trying to bend it.

 

Imagine that 1" pencil, not cut for writing. Now Imagine that pencil sharpened.

 

So many people changing the subject. Nemoo, what was your final finding? Were there and other symptoms like loss of boost? I have suspected I am having the same issue. I would expect smoke, a misfire or code with a leaky cylinder.

 

If it hasn't been done, check the valve stem seals.