Boost Leak causing crankcase pressure HELP!!

[SteveR6]

Well here we go again in this saga known as my car. Here's the whole story, sorry about the length. The T25 took a crap so I replaced with a 14B that supposedly had 10K on it since rebuild. I tried to boost leak test it the other day and could only get about 3 psi I noticed the valve cover breather was the source of the leak I also noticed I could hear oil bubbling or dripping back into the pan. So I think PCV and took it out to test it and sure enough after hooking it up to the air compressor and putting about 40 psi across it leaked (cheapo autozone one) checked out the stock one I had from another valve cover and it worked fine, put it in and got the same results. So I then say ok I'll go straight off the TB and cap the hose coming from the intake manifold. Low and behold I get a good boost reading and nice slow leakdown. So I take the plug out and put the PCV back in, same results, ruling out the PCV valve. Hooked up to the lower intercooler pipe and discovered my BOV is leaking (crap stock one) but was still able to get a decent boost reading. So I'm thinking it's the turbo, any thoughts? This Pi$#%^ me off royally as I just bought this thing and put it in. Would the fact I used the cylinder head oil feed and capped the fitting on the remote have anything to do with this? Also is it safe to drive my car as long as I don't run it hard until I can afford yet another turbo???

 

[SteveR6]

Forgot to mention I never tested the stock T25 so I don't know if the crankcase pressure was a preexisting condition or not.

 

[98gst14b]

It sounds like you got a bunch of blowby, the valve cover breather is nowhere in the intake system, it is leaking air from the crankcase. Which means you have bad blowby. What you should do is perform a compression test and see if your rings or other componets are fried. Good luck.

 

[donmagicjuan]

It sounds like you got a bunch of blowby, the valve cover breather is nowhere in the intake system, it is leaking air from the crankcase. Which means you have bad blowby. What you should do is perform a compression test and see if your rings or other componets are fried. Good luck.

I would agree with that, except he said he obtained good results when testing at the throttle body. SteveR6, have you started the car yet with the new turbo? It sounds like pressure is leaking across the seals in the turbo. If you haven't done so already, check for in-and-out shaft play and run the engine for a while (after priming the turbo, of course). My old T25 wouldn't hold pressure at all during a boost leak test right before I replaced it. It turns out it had about a millimeter or two of in-and-out play. Let us know what you find.

 

[SteveR6]

I can't feel any in and out play, that's not to say it's not there, but I don't feel any, has a tiny bit of up and down. Already did a compression test a week or so ago and it came out good on all cylinders, can't remember the exact specs though. The car ABSOLUTELY is not smoking in the least. WTF could this be it's driving me insane!!!!!!!

 

[SteveR6]

Also no oil in any intercooler piping, it's bone dry, a little in the intake but that's because of all the damn air coming out the valve cover breather I assume.

 

[brute]

Replace your PCV and dipstick. Or, you can just buy an automotive check valve.

A properly functioning PCV is supposed to be a one-way valve. The air coming out of the crankcase is supposed to circulate and then go into the intake manifold. From there, the air goes in to the cylinders to be burned.

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However, when the PCV is bad, it stops being a one-way valve. It then starts to allow boost from the intake manifold to enter the crankcase. This pressure has no where to go, and usually ends up popping the dipstick up, and escaping through the dipstick tube. This also causes oil to spray all over the engine bay.

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The rubber seal at the top of the dipstick also gets plastic-ey and brittle, and no longer seals. If you buy a new one (only like $17), the rubber should hold it in place. If you strap your dipstick down or bend the tube in such a fashion that the dipstick cannot pop out anymore, you better have enough money for a new motor.

 

[SteveR6]

My dipstick doesn't pop out. But I can feel air out of the oil cap hole if I remove it while the car is idling and I hear what I think is air escaping from the dipstick tube, but it doesn't pop out.

 

[SteveR6]

Let me see if I even understand how the PCV valve works. Under boost it pushes the ball back (in the direction of the valve cover and stops boost from entering correct? And then engine vacuum pulls the ball back toward the firewall and allows the pressure in the motor to escape correct? I checked operation of mine by taking it out of the car and hooking a hose up to the end that would face the firewall and pushed about 40psi through it with a blow gun on my air compressor, didn't feel any air coming out of the other end (the little brass tube). The junk Autozone one I had leaked air like crazy when I did this test. So i'm assuming my PCV valve is good to go.

 

[SteveR6]

Ok, let me ask this, if I'm right and vacuum opens the PCV shouldn't I be able to take the hose off the back while the car is idling and feel air?

 

[brute]

You have the PCV operation down. That's exactly what it's supposed to do. You could take different sides of the hose off, and feel air on the valve cover side. Conversely, if you take the hose off the PCV side, you should be able to feel vacuum from the intake manifold.

 

[SteveR6]

Ok, so apparently I stripped out the hole on the valve cover because when I went out to check the operation of the valve it just popped right out of the hole while I was trying to wiggle the hose off the back FANTASTIC! Anyway with the PCV still connected to the hose and the car idling I had vaccuum on my finger and the valve snapped closed when I took my finger off, I think it's working ok. I then removed it from the hose and she immediately wanted to die unless my finger was over the now empty hose going to the intake. I then had an epiphany and went and started my truck and opened the oil fill cap and low and behold there's air coming out of there so I'm guessing it's ok my car is doing that. There is still air coming from the valve cover breather hose though and if I pull out the dipstick I can feel air coming out of there too. Maybe the stripped hole is causing that in some way???!?!?!?

 

[brute]

The air circulation is normal, just not in high levels. Sounds like everything is working fine to me. Definitely fix the stripped hole right away.

 

[SteveR6]

I need to find someone with a properly running car and see if it's the same. Still don't understand why air is coming out of the valve cover breather. Nor do I understand why I hear oil bubbling or dripping if I try and boost leak test off the compressor AND get the air out the vc breather. If I test from the TB I get no air out of it, same as if I go off the LICP. I have such a love hate relationship with my car .

 

[SteveR6]

Wouldn't it stand to reason if I had excessive crankcase pressures I would throw SOME kind of code?? At any rate I'll be calling the Mitsu dealer first thing Monday morning to get another PCV, never hurts to be on the safe side for a $10 part I can write it off in my mind as "preventative maintenance" if it doesn't cure anything

 

[donmagicjuan]

If your turbo oil seals are leaking by, the pressure from the boost leak test could make it past the compressor into the oil return line and subsequently into the crankcase. If you're seeing satisfactory results when performing the test at the throttle body, then it can't be the PCV valve. My vote is for the turbo as the culprit.

 

[SteveR6]

Mine too, but I've also read that some leak by when performing the test is normal because the turbo isn't sealing up as if the car were running. Bottom line I guess is that I'm not smoking, not popping out the dipstick, the car runs pretty damn well. I'll keep the boost turned down to 9-10 like it is now fix the rest of the boost leaks and hope the turbo doesn't take a crap before I can put back enough money to replace it yet again.