Every OEM pcv valve leaks?

[matt97gst]

So I've tested 4 different OEM pcv valves. All of them passed the blow test. But when doing a boost leak test - at the throttle body elbow up to 20psi, with the pcv valve unscrewed from the valve cover to easier feel for air coming out - each one let out some air. I can describe the amount of air let out as if you were to blow lightly on the back of your hand.

So I'm a little stumped here - 4 OEM pcv valves ($10 from the mitsubishi dealer) all leak slightly when under pounds of pressure (don't leak when blowing into it). Unless someone can verify by doing the same test I did that no air comes out at all, this leads me to believe that they all let out a little air during boost. Probably not enough to tell a difference though.

I find it hard to believe that 4 different OEM pcv valves would all "fail" so maybe they just DO let out a little air.

 

[matt97gst]

Today I went to a different dealer and bought two more PCV valves. They both LEAKED! So that's 6 OEM PCV valves that all leak under pressure. I'm really dumbfounded here.

Do they have to be ran in the car for a couple days before they work correctly? What's the deal??

 

[underradar92]

Today I went to a different dealer and bought two more PCV valves. They both LEAKED! So that's 6 OEM PCV valves that all leak under pressure. I'm really dumbfounded here.

Do they have to be ran in the car for a couple days before they work correctly? What's the deal??

The concensus seems to be that 99% of oem valves leak & 99.9% of aftermarket ones do. Here is a thread on a way to (possibly) solve the problem. http://dsmtuners.com/forums/showthread.php?t=229338 I have the valve mentioned but I havent gotten around to installing it yet. Maybe I'll do it today, since I'm bored

 

[kenamond]

The concensus seems to be that 99% of oem valves leak & 99.9% of aftermarket ones do. Here is a thread on a way to (possibly) solve the problem. http://dsmtuners.com/forums/showthread.php?t=229338 I have the valve mentioned but I havent gotten around to installing it yet. Maybe I'll do it today, since I'm bored

Are you talking about setting it up as PCV--->Filter--->Check Valve--->IM?

I just p/m'ed FORMONTOYA to see if that setup was working for him. The filter+check valve would be dirt cheap ($4 for the fuel filter plus the cost of the check valve which couldn't be too much). And you could use a $2 Autozone/Carquest PCV valve just to get the metering function or just keep whatever leaky PCV was on your car already (unless it was clogged).

Anyway, let us know if you do this.

 

[underradar92]

Are you talking about setting it up as PCV--->Filter--->Check Valve--->IM?

I just p/m'ed FORMONTOYA to see if that setup was working for him. The filter+check valve would be dirt cheap ($4 for the fuel filter plus the cost of the check valve which couldn't be too much). And you could use a $2 Autozone/Carquest PCV valve just to get the metering function or just keep whatever leaky PCV was on your car already (unless it was clogged).

Anyway, let us know if you do this.

I just got done installing the PCV--->check valve--->IM. I decided not to use the filter. Everything works as normal (maybe better, or I'm getting placebo effect?), time will tell how long it lasts. I haven't got a logger so my deal isn't carved in stone as to how well it really works. I don't suppose seat o' the pants would mean anything, since I wasn't having any problems. It may show up at higher boost levels.

 

[kenamond]

I just got done installing the PCV--->check valve--->IM. I decided not to use the filter. Everything works as normal (maybe better, or I'm getting placebo effect?), time will tell how long it lasts. I haven't got a logger so my deal isn't carved in stone as to how well it really works. I don't suppose seat o' the pants would mean anything, since I wasn't having any problems. It may show up at higher boost levels.

Did you boost leak test with this in place? Did it leak at all at 20psi (or whatever)? If not, then you would only see problems at idle (I think). Also, does the PCV breathe in the correct direction? You could pull the PCV valve, put a plug in the VC, and start the motor and see if it draws air through the valve at idle. I think that as long as you're drawing air (ventilating the crankcase at idle), don't have idle problems, and hold back boost, it's working. This is usually when a wiseman comes in and says I'm an idiot.

 

[underradar92]

The pcv does draw in the correct direction, at idle a vacuum accumulates at the breather. I haven't done a boost leak test yet (ever... ), so that is also inconclusive, however, I am now confident that there is no boost leak past the pcv, at least. Probably will do one in the near future, I'll post the results in FORMONTOYA's thread. Unless he beats me to it.