1G Oil leak during boost leak test?

[Ski Bum]

I recently installed a FMIC along with an E316G. Today I performed a boost leak to test to make sure all of the clamps and so on were tight, no leaks, etc.

Firstly I couldn't get any more pressure than 14psi on my gauge although the compressor was set at 20psi. The oil cap and dipstick leaked the entire time. I could get 14psi if I put pressure on the oil cap.

I found a few leaks sealed them up and started up the car. It began to puke white smoke like a James Bond smoke screen. I took it for a drive and it smoked the entire time. It performed fine considering my SAFC settings are all out whack and need some time to tune. When I returned I noticed a HUGE puddle of oil where I had been parked. I checked everywhere and could not pinpoint the leak source. The oil filter housing had a little oil on the surface and the driver subframe had some oil on top. It also looked like the bolt that holds the clamp between the two halves of the turbo had a little oil on it but nowhere else. I jacked up the car, ran it, no leaks.

Could I have forced out oil during the boost leak test? I have done the same test numerous times before and never had this happen. WTF?

 

[kenamond]

I recently installed a FMIC along with an E316G. Today I performed a boost leak to test to make sure all of the clamps and so on were tight, no leaks, etc. Firstly I couldnt get any more pressure than 14psi on my gauge although the compressor was set at 20psi. The oil cap and dipstick leaked the entire time. I could get 14psi if I put pressure on the oil cap. I found a few leaks sealed them up and started up the car. It began to puke white smoke like a James Bond smoke screen. I took it for a drive and it smoked the entire time. It performed fine considering my SAFC settings are all out whack and need some time to tune. When I returned I noticed a HUGE puddle of oil where I had been parked. I checked everywhere and could not pinpoint the leak source. The oil filter housing had a litle oil on the surface and the driver subframe had some oil on top. It also looked like the bolt that holds the clamp between the two halves of the turbo had a little oil on it but nowhere else. I jacked up the car, ran it, no leaks. Could I have forced out oil during the boost leak test? I have done the same test numerous times before and never had this happen. WTF?

Is your VC breather plugged when you do the boost leak test? Sounds like you were pressurizing your crank case. Any ring blowby, valve stem seal leaks, or a bad PCV leak during a boost leak test need to escape out the VC breather, or you're pressurizing the crank case (I don't see how pushing on the oil cap should affect leak test pressure unless you're pressurizing your crankcase). If you blew the turbo seals during the leak test, you may have pumped oil into your LICP and IC that your motor then slurped up and burned. You may have damaged other seals in your engine, but it's hard to say.

Check your LICP for gobs of oil. The lowest point on your intake after the turbo may be full of oil. What is the oil level in your engine?

Also, you should boost leak test on a warm motor. You'll have much higher blowby on a cold motor.

And if your PCV is shot, you could have been flooding the crankcase with 20psi through that. Did you check your PCV?

I don't want to scare you, but check this stuff out. The oil would have me concerned.

 

[Ski Bum]

Is your VC breather plugged when you do the boost leak test? Sounds like you were pressurizing your crank case. Any ring blowby, valve stem seal leaks, or a bad PCV leak during a boost leak test need to escape out the VC breather, or you're pressurizing the crank case (I don't see how pushing on the oil cap should affect leak test pressure unless you're pressurizing your crankcase). If you blew the turbo seals during the leak test, you may have pumped oil into your LICP and IC that your motor then slurped up and burned. You may have damaged other seals in your engine, but it's hard to say.

Check your LICP for gobs of oil. The lowest point on your intake after the turbo may be full of oil. What is the oil level in your engine?

I just pulled the licp and no oil there, I added about 8-10oz of oil to reach the right level.

Also, you should boost leak test on a warm motor. You'll have much higher blowby on a cold motor.
The engine was fully warmed

And if your PCV is shot, you could have been flooding the crankcase with 20psi through that. Did you check your PCV?

I replaced the PCV after the test but it seemed fine, the little piece inside was still rattling around.

I don't want to scare you, but check this stuff out. The oil would have me concerned.

Believe me my heart stopped when I saw the puddle.

Where else could the oil have gone to cause all of the smoke for that period?

 

[kenamond]

Does your engine still smoke?

Just because the PCV rattles doesn't mean it's good. Next time you boost leak test, pull the PCV out of the VC and see if it leaks under pressure.

First, though, I'd make sure your VC breather isn't blocked. It doesn't make sense that pushing on the oil cap would affect your boost pressure, because you should be leaking that air out the VC breather. If there's no way out, you're pressurizing the crank case which is bad.

If you have really low compression, you could be leaking a lot into the crank case and head. Have you done a compression test recently?

Anyway, I'd check your PCV again first and go from there.

 

[Ski Bum]

Does your engine still smoke?

Just because the PCV rattles doesn't mean it's good. Next time you boost leak test, pull the PCV out of the VC and see if it leaks under pressure.

First, though, I'd make sure your VC breather isn't blocked. It doesn't make sense that pushing on the oil cap would affect your boost pressure, because you should be leaking that air out the VC breather. If there's no way out, you're pressurizing the crank case which is bad.

If you have really low compression, you could be leaking a lot into the crank case and head. Have you done a compression test recently?

Anyway, I'd check your PCV again first and go from there.

Thinking about it now wouldnt the crankcase pressurize with the vc breather hos still attached to the intake plenum? Once the air is inside the crankcase where can it go? Out of the oil cap and dipstick, right?

When I pushed on the oil cap the leak would lessen thereby increasing the pressure the boost gauge was seeing. I was only able to get it to hold 13-14psi.

My compression is on the lower end of the scale. I cant remember exactly but I want to say around 130-140 across the board.

I noticed today pools of oil between the lower runners of the intake manifold. It's hard to tell where it may have come from. If I was pressurizing the crankcase and/or head where could the oil have come from?

 

[kenamond]

Thinking about it now wouldnt the crankcase pressurize with the vc breather hos still attached to the intake plenum? Once the air is inside the crankcase where can it go? Out of the oil cap and dipstick, right?

When I pushed on the oil cap the leak would lessen thereby increasing the pressure the boost gauge was seeing. I was only able to get it to hold 13-14psi.

My compression is on the lower end of the scale. I cant remember exactly but I want to say around 130-140 across the board.

If you boost leak test at the compressor inlet, and the VC breather runs to the intake pipe, which you've disconnected from the compressor inlet, then the VC breather is the escape point from the crank case. That's actually one of its purposes. There are oil return passages in the head that run from under the VC back down to the oil pan, so any crankcase pressure can easily escape up to the VC and out the breather.

Pull the VC breather off the VC or off the intake pipe and make sure it is leaking boost leak test air. If it's blocked, there is no other way out of the crank case other than the oil cap, dipstick tube....or seals. You want that air to leak out the VC breahter - it's part of the PCV system, and part of its job is to relieve crank case pressure when the motor is under load (ring blowby during the compression stroke has to get out of the system somewhere, and the design is to let it go out the VC breather and back into the intake tract so that it can get a second chance at being combusted; because it leaks during the compression stroke, it's a air/fuel mix that hasn't yet burned).

I'm confused by your other post where you said you were seeing pools of oil under your "lower runners of the intake manifold". The runners are all the same hieght; there aren't "lower runners". Could you explain that a bit more. The source of the oil will help a lot in trying to figure out the problem.

 

[chanley talon]

I would check and see if you dont have a crack in your vavle cover back there letting oil come out under boost.

 

[Ski Bum]

The lower runners I'm referring to are the lower section of the intake manifold runners. I guess my terminology was'nt right. The oil is on top of the lower section of the intake manifold runners. So the inatake manifold is shaped like a "C", the oil is on top of the inside portion of the "C" where it connects to the head.

 

[oldman]

I noticed today pools of oil between the lower runners of the intake manifold. It's hard totell where it may have come from. If I was pressurizing the crankcase and/or head where could the oil have come from?

Like Mack said, instead of figuring out why there is pressure under the valve cover by listening under the oil cap, you pressed on the oil cap and allowed pressure to build up in the crankcase resulting in blown valve seals and probably more.

 

[Ski Bum]

Like Mack said, instead of figuring out why there is pressure under the valve cover by listening under the oil cap, you pressed on the oil cap and allowed pressure to build up in the crankcase resulting in blown valve seals and probably more.

14psi is enough to damage the valve seals?

Instead of doing the boost leak test directly from the compressor inlet I hooked up to the intake plenum. Doing so I pressurized parts of the system that do not see pressure and pressurized the VC breather in the wrong diection. So the right way is directly to the compressor inlet, right? Should the VC breather remain open on the end that normally connects to the intake plenum? Once the system begins to pressurize should there ever be pressure within the crankcase that would escape out of the VC breather, oil cap or dipstick?

 

[oldman]

1. The breather doesn't go to the intake manifold, it goes to the intake pipe. PCV vlave on the other hand, goes to the intake manifold.

2. Re-test at the TB elbow, always open your oil cap so pressure doesn't build up in your crankcase. Pressure in the crankcase (same as leakage at oil cap, dipstick, breather...etc.) means air is entering the crankcase via, turbo seal (normal under a static test), pcv valve, valve seals or excessive blow by/piston rings. The purpose of the test is to find out why pressure is building in the crankcase, sealing it off like you did will do nothing but damaging internal seals and external gaskets.

 

[Ski Bum]

1. The breather doesn't go to the intake manifold, it goes to the intake pipe. PCV vlave on the other hand, goes to the intake manifold.

2. Re-test at the TB elbow, always open your oil cap so pressure doesn't build up in your crankcase. Pressure in the crankcase (same as leakage at oil cap, dipstick, breather...etc.) means air is entering the crankcase via, turbo seal (normal under a static test), pcv valve, valve seals or excessive blow by/piston rings. The purpose of the test is to find out why pressure is building in the crankcase, sealing it off like you did will do nothing but damaging internal seals and external gaskets.

I retested today, this time with the leak tester hooked up to the compressor inlet. The VC breather was left open on the end that normally attches to the intake pipe. Air was constantly escaping through the VC breather tube. If I took the oil cap off I could also hear air entering/escaping through there as well. With the air compressor set at 20psi my boost gauge only registered 14psi.

Is that the correct way to test for leaks? How much pressure should build performing the test this way? Should I have seen 20 psi at my boost gauge? With air escaping through the VC breather and oil cap is the 14psi seen in the system enough to expose possible boost leaks?

 

[oldman]

Retest tomorrow from the throttle body elbow to exclude the turbo seal as a possible leak source. Continue to record the pressure difference between the regulator gauge and boost gauge as well as estimating the amount of leakage under the VC.

 

[kenamond]

I retested today, this time with the leak tester hooked up to the compressor inlet. The VC breather was left open on the end that normally attches to the intake pipe. Air was constantly escaping through the VC breather tube. If I took the oil cap off I could also hear air entering/escaping through there as well. With the air compressor set at 20psi my boost gauge only registered 14psi.

Is that the correct way to test for leaks? How much pressure should build performing the test this way? Should I have seen 20 psi at my boost gauge? With air escaping through the VC breather and oil cap is the 14psi seen in the system enough to expose possible boost leaks?

Sounds like you're testing correctly now. Make sure it's a warm motor, because the combustion chamber doesn't seal nearly as well cold (valve seals and ring blowby).

First thing to test is the PCV. Unscrew it from the back-passenger side of the VC but leave it attached to the hose that goes to the intake manifold. Repeat your boost leak test and check if air is coming out the metal tube on the end of the PCV valve. If it's leaking air (more than just a little bit at 20psi) replace it with an OEM valve (go to your nearest Mitsu dealership and get one for $5 or so). The Autozone, etc. ones won't work.

If your PCV is not leaking or if you replace it and still get excessive leaks out the oil cap or VC breather (with a warm motor), do the boost leak test on your throttle body elbow and see if it improves. If it doesn't, I recommend a compression test, because you're leaking air from the combustion chamber into the head/crankcase which can only occur if you have poor compression.

Let us know how it goes, and we'll help you get through this.

EDIT: Ack...pulled away from computer without hitting submit.

 

[oldman]

The only thing missing from Mack's post is consideration for valve seals/guides.

 

[kenamond]

The only thing missing from Mack's post is consideration for valve seals/guides.

Thanks, Bruce. I keep forgetting they're outside the combustion chamber. And the only consideration that could be added is *intake* valve guide seals.

 

[oldman]

Thanks, Bruce. I keep forgetting they're outside the combustion chamber. And the only consideration that could be added is *intake* valve guide seals.

No problem. I actually think the problem is valve seals, the test from TB elbow without the pcv valve combined with a dry and wet compression test will help verified my suspicion but oil dripping out of the runners is a clear give away.

 

[kenamond]

No problem. I actually think the problem is valve seals, the test from TB elbow without the pcv valve combined with a dry and wet compression test will help verified my suspicion but oil dripping out of the runners is a clear give away.

If I'm reading his post correctly, it sounds like the oil is on the exterior of the IM, so if oil's getting there, it wouldn't be from valve seals, right? I'm not saying his boost leak problem isn't related to valve seals, but I'm missing how that would have anything to do with the oil leak.

 

[oldman]

If I'm reading his post correctly, it sounds like the oil is on the exterior of the IM, so if oil's getting there, it wouldn't be from valve seals, right? I'm not saying his boost leak problem isn't related to valve seals, but I'm missing how that would have anything to do with the oil leak.

If the oil is around the IM flange, it can very well be coming from intake valves seals while the car is under vacuum. If this is true, boost is probably leaking straight into the crankcase through the intake valve seals and either blowing right out of exhaust valve seals, or back up the turbo oil return line due to excessive crankcase pressure. All thses are just speculations, the key is the additional leak test and compression test results.