Vent on valve cover...is it okay to be open?

[dunebuggyjay]

Hi guys, the large hose (and the smaller hose) that come off the corner of the valve cover. Mine are open to atmosphere. I am having issues with my car running right. (s52 converted to obd1)

Would this be considered a vacuum leak? My original intent was to put this hose into a catch can at some point.

Just wondering if i am running around for nothing ...checking everything else because my car runs like crap, when it could just be this. LOL

Should there be a one way valve in the hose? Right now it is just open. I can blow and suck into it. LOL

Thanks
Jay

[M-technik-3]

no close it you have a giant vacuum leak now.

[dunebuggyjay]

Really? I would have thought this would have nothing to with engine vacuum in the manifold. Im turbo, so i really dont want to plumb this back into my intake. I thought alot of guys run catch cans...that are open to the atmosphere.

My car is ripped apart again right now, to replace a turbo drain hose, so I can test it to see if there is vacuum there while running.

Jay

[M-technik-3]

Oh turbo might be different I am not FI so that is not my realm.

[dunebuggyjay]

Well I guess a vacuum leak is a vacuum leak.

If its considered a leak on a N/A, then I would assume turbo would be the same thing. If I had all the oem stuff from the s52, i would put it back on...but sadly it was not included when I took the engine out of the car. They had that hose plumbed back into the intake right before the airfilter. (it was turboed when I bought the engine)

im not sure how that compares to just being open to atmosphere though. Or how the DME see's it.

I'll check it out once my car is back together. I'll see if I get vacuum on that hose when running.

Thanks
Jay

[ak-]

Nooo, if your car is turbocharged that port on the valve cover needs to be vented to atmosphere because there is positive pressure inside that needs to be relieved.

Your troubles lie elsewhere. Is there smoke coming out of it on idle? Like thick smoke?

[dunebuggyjay]

Nooo, if your car is turbocharged that port on the valve cover needs to be vented to atmosphere because there is positive pressure inside that needs to be relieved.

Your troubles lie elsewhere. Is there smoke coming out of it on idle? Like thick smoke?

No, No smoke coming out.

Is that plastic piece in the valve cover supposed to be a check valve type thing. Like a PCV valve?

I can blow and suck both ways on mine.

Someone on another forum was saying how a leaky oil cap was giving them running issues...so i started looking at my vent hose...and noticed its just like having a leaky oil cap.

Thanks for the help.

Jay

[Sh3rpak!ng]

the vent off the valve cover is not a vacuum leak, you just need to make sure the other end of that vent, where the hose would've connected the valve cover to the intake tract, is plugged. The valve cover vent, oil cover seal, dipstick tube seals will only induce a vacuum leak if the crankcase is connected to the intake tract.

Is the bung on the dipstick (normally drains oil from the cyclone separator) plugged? If it's still somehow connected to the intake tract, that'll cause a vacuum leak since your valve cover is vented to atmo.

If you're FI, you most definitely need that vent open and not plumbed into the intake tract. A vented catch can is a good idea to collect all the oily residue rather than spitting it all over your engine bay.

[dunebuggyjay]

the vent off the valve cover is not a vacuum leak, you just need to make sure the other end of that vent, where the hose would've connected the valve cover to the intake tract, is plugged. The valve cover vent, oil cover seal, dipstick tube seals will only induce a vacuum leak if the crankcase is connected to the intake tract.

Is the bung on the dipstick (normally drains oil from the cyclone separator) plugged? If it's still somehow connected to the intake tract, that'll cause a vacuum leak since your valve cover is vented to atmo.

If you're FI, you most definitely need that vent open and not plumbed into the intake tract. A vented catch can is a good idea to collect all the oily residue rather than spitting it all over your engine bay.

Okay that makes sense. Yea, I had to totally redo the intake tract, so I only added a bung for the ICV. And a few vacuum ports for BOV, wastegate etc.

I dont have a bung on the dipstick tube.

I guess Im fine then. (which is what I originally thought) Other than making a mess of my engine bay with the oil coming out of the hose. (which is really nothing at the moment.) I'll have to see where the hell I can mount the catch can at some point.

The few posts i read about vacuum leaks from dipstick tube, oil cap etc had me scared. LOL. But it makes sense if you have some of the intake tract plumbed back into the crankcase. (which i do not)


Thanks,
Jay

[M3PO]

+1 to this

the vent off the valve cover is not a vacuum leak, you just need to make sure the other end of that vent, where the hose would've connected the valve cover to the intake tract, is plugged. The valve cover vent, oil cover seal, dipstick tube seals will only induce a vacuum leak if the crankcase is connected to the intake tract.

Is the bung on the dipstick (normally drains oil from the cyclone separator) plugged? If it's still somehow connected to the intake tract, that'll cause a vacuum leak since your valve cover is vented to atmo.

If you're FI, you most definitely need that vent open and not plumbed into the intake tract. A vented catch can is a good idea to collect all the oily residue rather than spitting it all over your engine bay.