can oil leak out of a pcv valve?

[bigjon33880]

i thought my valve cover was leaking until i looked closer and it was coming out from around the pcv valve

 

[Skandocious]

I assume you've got the kind where the PCV valve is just stuck directly into the valve cover, no hoses inbetween? Where is it leaking...? At the SEAL between the PCV and the valve cover?

 

[bigjon33880]

it seemed like it was coming out of the actual valve. i disconnected the L shaped hose and oil came out of it to. not puring out but enough to run down the valve cover onto the manifold

 

[Skandocious]

Well it's either gonna be the PCV valve or the grommet. I'd just replace both and be done with it, they're cheap parts. Can you give me the info on the truck? Make/model/engine/

 

[Skandocious]

In case you don't know (and I'm sure you do). PCV = positive crankcase ventilation. The valve is used to circulate gas vapors back into the intake where they can be put back into the combustion chamber. You can imagine that gas isn't always the only thing making its way through the valve, so it's pretty normal to get some oil in there every once in a while...

 

[bigjon33880]

88 F150 Efi351

 

[Skandocious]

Yeah I would just replace the PCV and grommet. Shoot a PM to our sponsor ---

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[eco]

The only thing that I can think of would be a PVC valve that is bad and thus appliying too much vacuum to the crankcase thus sucking oil in addition to the vapors that it is supposed to suck up and inject into the plenum.

 

[Lost]

If blow by gets bad enough it will find all sorts of places to come out. But swapping a new set . Bet it takes care of it.

 

[Fellro]

I have actually seen some with blowby so bad it came out the dipstick tube. It is possible, however, that just the valve is stuck, so the pressure has to go somewhere, and that was a spot it could get through.

 

[eco]

Blow-by sprays oil up the other valve cover and into the breather which ends up all over the air filter on these rigs. Thats always been my experience anyways.

 

[Fellro]

That would be as long as the pcv is opening... if it is stuck closed, it would go wherever it can get out. Since the pcv opens, letting the pressure get out, normally, you would be accurate. Stuck closed, it would then go out the breather tube.

 

[bigjon33880]

new problem

i replaced the pcv valve and the L shaped hose that goes to the valve cover, it seemed to take care of it, thanks. but we cant stop here, i have another problem. i gave it a tune up, plugs, wires, cap, rotor, oil change. i have a miss and rough idle that will not go away. it has a new fuel filter, but if that got clogged a little would that give it a miss? this truck did sit with almost empty tanks for 3 years until i got it 3 weeks ago.

 

[Skandocious]

Did the miss come after the tune up or was it already there? Did the tune up affect it at all?

 

[bigjon33880]

it ran great for a little while after the tune up but it has a hesitation when i get on the gas could i need another fuel filter

 

[bigjon33880]

it runs good at a higher idle but when i let off the gas it chokes and coughs and sputters and then it start to act like its going to die

 

[Skandocious]

Might want to try cleaning your IAC (idle air control valve). If it gets gunked up it can cause a nasty idle. It's mounted to the throttle body:

Have you tried reading the codes lately?

 

[bigjon33880]

the check engine light isnt coming on but i guess i could still try. im thinking it still could have bad gas in it but im not shure. i drained the tanks with the pumps, just unhooked the lines, and put in some high octane with some heat and changed the fuel filter again. it straitened up a little, the damdest thing though i let it run high idle 2200-2500 rpms for about 10 min and it started over heating.I hope it was just me and what i thought i fixed with a new guage isnt something bigger. im going to put in a different thermostat and try again. hopefully it doesnt over heat again. maybe i wont run it as hard. it seems to do alright going up and down the road, it sits between 190 and 210 depending on what i am doing.