have you tried to do the basics? an oil treatment could be all you need, some kind of oil detergent. how long between oil changes had it been? could be fouled up oil sending unit, or plugged up passage/line. hell ive seen people who "change their own oil" but never change the filter, then one day the filter backs off the threads and their leaking like sieve. i change my oil once a year full synth, new filter. my oil never comes out as black as some of the shit ive seen in my day. hell ive seen sludge come out of engines, not oil, but thick creamy crap.

Is your pcv valve plugged or line to your intake off the vc plugged? Just trying to think it could be pushing past the seals from excess pressure.

tryingtofixthis said:

have you tried to do the basics? an oil treatment could be all you need, some kind of oil detergent. how long between oil changes had it been? could be fouled up oil sending unit, or plugged up passage/line. hell ive seen people who "change their own oil" but never change the filter, then one day the filter backs off the threads and their leaking like sieve. i change my oil once a year full synth, new filter. my oil never comes out as black as some of the shit ive seen in my day. hell ive seen sludge come out of engines, not oil, but thick creamy crap.

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What does all that have to do with oil leaking from the valve cover bolts?

Oil pressure has nothing to do with it because there is no pressure around those areas. 80psi on startup is common cold, even higher I would expect without balance shafts and no passage (head, oil sender) porting work done.

There are two common reasons. 1) crankcase pressures is pushing oil past the rubber gasket, and it will wick up the bolt and out, and more commonly 2) cracked valve cover. Even a hairline crack will allow oil to seep through when it's nice and warm.

Crankcase pressures come from blowby, poor quality or worn valve stem seals, broken pcv valve as dsmspick (is that a slur?) said.

The pcv is new oem about a month ago the engine it is rebuilt 5000 miles ago.

johnboyrs said:

The pcv is new oem about a month ago the engine it is rebuilt 5000 miles ago.

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That doesn't mean anything at all. The oem pcv valve is garbage! It can leak right out of the box. If you haven't taken it out and checked it with pressure I would do that. Either way you need to run one of these, period.

3/8" Kynar® Standard Check Valves | U.S. Plastic Corp.

Good to 150psi and guaranteed not to leak. Oh yeah... super cheap too!

It's happening the same to me, plus it leaks from the gasket all around. The place where the spark plug wires are in gets wet from oil as soon as I go for a short road drive. The engine is all stock, the cover was never open so I believe the gasket, cover and bolts torque must be the way it suppose to. Will check the pcv. Anything else?

Mike_GST said:

It's happening the same to me, plus it leaks from the gasket all around. The place where the spark plug wires are in gets wet from oil as soon as I go for a short road drive. The engine is all stock, the cover was never open so I believe the gasket, cover and bolts torque must be the way it suppose to. Will check the pcv. Anything else?

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Has the gasket been replaced? It's a rubber gasket... They dry out over time.

Gasket is probably junk, and make sure you have good crankcase ventilation.

Agreed on all the above mentions of crank case pressure. These cars are notorious for issues from that (blowing the dip stick out of the tube). That's where I'd start if you're certain the gasket is good and the bolts are tightened to spec.

Mike_GST said:

The engine is all stock, the cover was never open so I believe the gasket, cover and bolts torque must be the way it suppose to. Will check the pcv. Anything else?

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The gasket goes bad over time. Get a felpro vc gasket set from rock auto for $10 and make sure you tighten to spec (only slightly more than hand tight) in an alternating pattern. Every DSM I ever bought was leaking from the vc and every time it was fixed with a new gasket.

I'm suspicious about engine "ventilation" (pcv maybe or bad crankcase ventilation) beacuse when I go down hill without pressing throttle, the engine sounds weird and it brakes the car more than used to. Also when accelerating, turbo sounds loud but the car goes slow.

Does it ever puff smoke out of the oil filler cap hole when you remove it and the motor is running???

Did some tests yesterday and I couldn`t conclude if the PCV it's working fine or not.
I understand the intake manifold, as long as turbo doesn`t build boost, is under vaccum and suppose to keep the PCV valve open and draw the gases from blow by. This way I guess is working fine, like I tryed to show on this little video. You guys also can see the amount of oil retained over the valve cover. I just had it cleaned and happened again after a short drive on the road.


What I don't know is what suppose to happen to the PCV valve when turbo comes in. Should the PCV close all the way? By chance would turbo pressurize back the engines head and the crankcase? And would those 11-13 psi be enough to make braking down the engine and leaking oil all over valve covers and oil sumps gaskets?
This video below I simulate 13psi of pressure coming from the manifold to the valve cover and the PCV ability (or not) of holding this pressure. Looks like it doesn't. So would the PCV to be condemned?


I'm adding some pictures taken from the mess of oil underside of the engine. I tightened the oil filter by hand as far as I could and still some oil is also leaking from there, never happened before.








There's no smoke comming from the oil filler cap. The dip stick also never moved up a bit. Recently I did a compression test and got all 4 cylinders between 175 and 185psi. Its all stock, has only 37.5k miles on it. I drive this car no more than 2k miles a year and replace oil (Catrol 5w40, 10w30, 10w40) and filter (fram/sogefi) religiosly every year. By the way, I replace the oil and filter last week and nothing changed. The engine supposed to be TIP TOP! Please help.

First off throw that junk Fram filter as far as you can, go to a factory Mitsubishi filter, if the pcv valve wont hold when you blow air backwards into it, then its junk, for the cost just replace it anyway to eliminate it. When under boost it should seal off and the turbo intake should be sucking the crankcase fumes into the inlet of the turbo and pulling a slight vacuum on your crankcase, how is the turbo? if its not boosting good and your getting pressure into the crankcase its a suspect also at this point, especially if its original.

I use a one way check valve in the pcv line to prevent it from leaking under boost just like I do in the brake booster line.

General PSA: The PCV valve IS a METERED one-way check valve, and that's all it is. If it leaks air in more than one direction, clean the grit (a few grains can cause leaks!) out with carb cleaner and check it again, and if it still leaks then replace it with an OEM unit. I disagree that OEM PCV valves are garbage, and I can show you several that are still good after almost 300k miles and/or 22 years.

FWIW I once purchased 3 aftermarket PCV valves from AutoZone and all 3 of them were defective out of the box (could blow air through them both directions), despite AutoZone's illustrators obviously knowing what a good PCV valve is supposed to act like:

The first time it was leaking air from intake to VC direction. The second time didn't. I had used carb cleaner. Anyway, I will give another shot letting it sit on the carb cleaner and test it again with 13psi. I'd replace it with a new one but I can't find it in here. So if cleaning it won't solve the problem I'm gonna need improvise with a newer model car PCV ...or order it from USA through ebay.

But all this oil leaking mess could be just because of this got damn valve?! Or should I get prepared for something else? As far as I know turbo boost well and pressure hits 11 psi right away.

Something I forgot for you to check also is the gasket on the oil cap. Where the oil is collecting on the VC says oil cap gasket to me.

Clean that valve really well Mike... I believe you can fix it without having to replace it. Spray in some carb cleaner, cover the ends with your fingers, and shake it. Then, repeat soaking in carb cleaner and blowing out with compressed air a few times.

Also, when you blow through it with your mouth, you have to FROWN MORE as in the picture! Intense frowning intimidates the PCV valve while preventing your eyeballs from popping out.

And then, as others also suggest: Replace your valve cover gasket and your oil cap gasket. Those pieces of rubber harden and crumble over time, in as little as 4 years in some conditions!
When you tighten the valve cover bolts, be careful because you can CRACK the valve cover if you tighten the bolts too much or too unevenly. If you crack the valve cover, oil will forever leak from the cracked area(s).

Watch the last 7 minutes of this excellent video, too. He shows the best way to reinstall the valve cover gasket set properly. There is a specific sequence you should tighten the bolts, and the torque spec is 36 INCH-pounds (2-3 foot pounds max). The goal is to evenly distribute the clamping force across the entire valve cover so that the cover rests flat and parallel to the head. The rubber gasket "squishes" to provide the seal without requiring much bolt torque.

jsmcpn said:

I disagree that OEM PCV valves are garbage, and I can show you several that are still good after almost 300k miles and/or 22 years.

FWIW I once purchased 3 aftermarket PCV valves from AutoZone and all 3 of them were defective out of the box (could blow air through them both directions), despite AutoZone's illustrators obviously knowing what a good PCV valve is supposed to act like:

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Back in the day when Mitsubishi was actively selling turbo cars you could count on getting a PCV that sealed under boost. I've got several that still do (Part of the normal factory service was to change them regardless of condition) but once the DSM's went away the only cars using this style PCV were NA and the part spec must have changed because the dealership parts then started failing just like those sourced everywhere else.

IIRC, For awhile people were swapping to Hyundai covers and studs, those used to leak oil because the studs were designed to have seals under the nuts.

steve said:

Back in the day when Mitsubishi was actively selling turbo cars you could count on getting a PCV that sealed under boost. I've got several that still do (Part of the normal factory service was to change them regardless of condition) but once the DSM's went away the only cars using this style PCV were NA and the part spec must have changed because the dealership parts then started failing just like those sourced everywhere else.

IIRC, For awhile people were swapping to Hyundai covers and studs, those used to leak oil because the studs were designed to have seals under the nuts.

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Ahh, that sucks. I hadn't considered OEM part quality going down over time... guess that is what happens when your DSM sits on stands for a full decade! In that case, I say we all try to round up as many "vintage" PCV valves that we can (and send one to Mike in Brazil), because I bet most of them are perfectly good other than being dirty.

jsmcpn said:

Clean that valve really well Mike... I believe you can fix it without having to replace it. Spray in some carb cleaner, cover the ends with your fingers, and shake it. Then, repeat soaking in carb cleaner and blowing out with compressed air a few times.

Also, when you blow through it with your mouth, you have to FROWN MORE as in the picture! Intense frowning intimidates the PCV valve while preventing your eyeballs from popping out.

And then, as others also suggest: Replace your valve cover gasket and your oil cap gasket. Those pieces of rubber harden and crumble over time, in as little as 4 years in some conditions!
When you tighten the valve cover bolts, be careful because you can CRACK the valve cover if you tighten the bolts too much or too unevenly. If you crack the valve cover, oil will forever leak from the cracked area(s).

Watch the last 7 minutes of this excellent video, too. He shows the best way to reinstall the valve cover gasket set properly. There is a specific sequence you should tighten the bolts, and the torque spec is 36 INCH-pounds (2-3 foot pounds max). The goal is to evenly distribute the clamping force across the entire valve cover so that the cover rests flat and parallel to the head. The rubber gasket "squishes" to provide the seal without requiring much bolt torque.

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More carb cleaner and intense frowning unfortunately didn't make it better!
PCV valve is leaking sometimes less, sometimes more. If the VC side of the PCV is down leaks less (because of the gravity helping to force the ball against its seat), otherwise air flows free.
Probably the PCVs spring lost its function. It's still inside but it moves free as well as the ball and I think that's not right.
Will se what I can do with what I'll find around here and let you guys now the result.
Happy new year.

Check valve.

Oh s**t, I found it