What kind of PCV valve is this???????

["Turbo-T"]

This was used as the PCV valve in my car when I bought it:

Here it is next to my new AC Delco PCV that I ordered thru the Buick dealership:

But when you shake it, there is no rattle noise that you'd typically get with a PCV.

Anyone ever seen one like it?

 

[lhbarrett]

It appears to be an older style (homemade) check valve. Can it pass air in both directions or just one?

 

[TurboDave]

it's not a PCV, that looks like one of the old ATR check valves. It's OK to run it in series with the PCV if you like (above the PCV), but don't run it in place of the PCV.

 

["Turbo-T"]

it's not a PCV, that looks like one of the old ATR check valves. It's OK to run it in series with the PCV if you like (above the PCV), but don't run it in place of the PCV.

And do you know where it was at???? It was found on the right side of the intake manifold. It was inserted into the round grommet in the intake with a tube off of the throttle body running into it.

I may be mistaken but I believe someone was trying to use it as a PCV....here take a look at this pic please:

It appears to be an older style (homemade) check valve. Can it pass air in both directions or just one?

If I try to blow thru the wider end (end with the threads and cross) at first nothing seems to happen, then you hear a small pop (as if the valve inside is freeing itself loose) and I can manage to blow air thru it then but not very much.

If I try blowing air thru at the smaller side (barbed side where hose attaches) I can't get anything to go thru.

 

[TurboDave]

Some people use it as a PCV replacement to try and keep boost out of the block. Not a very good idea at all, since the actual PCV that goes there is a calibrated to pass a certain amount of air in the vacuum direction, and the check valve isn't. The check valve flows way too much air in the vacuum direction and throws off the amount of air entering the engine that the ECM calculated based on what passes through the MAF plus the amount already "figured" for going through the "correct" PCV.

 

[vacuum 6]

I used the ATR one (not in line with stock PCV) for years and years on my stock motor with zero issues then used it on my new motor and it sucked oil.

 

["Turbo-T"]

Turbo Dave, I am guessing you would highly recommend I not ever reinstall the check valve I just replaced?

Hhhmm....keeping boost out of the block? I guess I always thought air passing over the hose that runs to the PCV would create a vacuum to vent the block of blow by and such.

Not to sound silly (still learning my TR's :wink: ) but how often does boost get in the crank case? Is this a bad thing?

 

[TurboDave]

Turbo Dave, I am guessing you would highly recommend I not ever reinstall the check valve I just replaced?

Hhhmm....keeping boost out of the block? I guess I always thought air passing over the hose that runs to the PCV would create a vacuum to vent the block of blow by and such.

Not to sound silly (still learning my TR's :wink: ) but how often does boost get in the crank case? Is this a bad thing?

Yes, you're right, the PCV vents the block with vacuum. However, that same hose sees boost pressure when under boost. The PCV doesn't seal perfectly and lets some boost bleed by. Some think that's a bad thing to blow some boost into the block and pressurize it. However, with all the block venting there's not going to be any pressure building from that source.

 

["Turbo-T"]

The PCV doesn't seal perfectly and lets some boost bleed by.

Dumb q. but when it allows boost to "bleed by", does the boost bleed around the grommet where the PCV goes in? or do you mean it bleeds out the other end of the PCV into the block?

 

[TurboDave]

Boost that gets past the PCV just goes into the block. But since about 99% of these cars have had their stock sealed block breather system modified with valve cover breathers, it all escapes through the breathers, etc.

 

["Turbo-T"]

Found it, on SE Turbo. P/N ENGPVC1100 PCV SHUT-OFF CHECK VALVE

Buick, turbo buick, grand national, ttype, gnx, 3.8, regal, 84-87

 

[WS6]

I found that one in mine too, replaced it for the helluva it with an autozone PVC and noticed an improvement in idle quality...wierd?

 

["Turbo-T"]

I've noticed no difference in mine but I kept it just in case, I did shoot them an email asking the purpose of it as I'm still a little confused.