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Bad PCV Valve ?
- Thread starter joe944
- Start date
I'm not sure but I think it's quite possible. For $3 and 30 seconds labor, I'd just replace it. (I just did mine yesterday and don't think there was anything wrong with it, however the old one would pass air freely in the right direction but the new one has a lot more of a restricted air flow in the free flow direction,... I could see the old one drawing in oil much easier).
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The thing that can fail with the PCV valve itself is it can become clogged with sludge and carbon so it cant ventilate. The spring in the valve can get coated with carbon & sludge and it wont open and close when needed; which will cause the crank case to build up pressure and create what is known as "blow by." Blow by is when oil is forced passed the piston rings into the combustion chamber. So the answer to your question is YES.
There are other reasons that can cause oil to leak into the combustion chamber...failing piston rings, scores and/or scratches on the cylinder walls.(will need to be honed) Cracked head, failing head gskt.....someone chime in if I left anything.
How much oil are we talking about here? out
There are other reasons that can cause oil to leak into the combustion chamber...failing piston rings, scores and/or scratches on the cylinder walls.(will need to be honed) Cracked head, failing head gskt.....someone chime in if I left anything.
How much oil are we talking about here? out
The thing that can fail with the PCV valve itself is it can become clogged with sludge and carbon so it cant ventilate. The spring in the valve can get coated with carbon & sludge and it wont open and close when needed; which will cause the crank case to build up pressure and create what is known as "blow by." Blow by is when oil is forced passed the piston rings into the combustion chamber. So the answer to your question is YES.
There are other reasons that can cause oil to leak into the combustion chamber...failing piston rings, scores and/or scratches on the cylinder walls.(will need to be honed) Cracked head, failing head gskt.....someone chime in if I left anything.
How much oil are we talking about here? out
Cylinder one was dripping. Nothing on the electrode. Cylinder 3 had a little I just wiped off. 2 and 4 had a little residue under where it screws in. Plugs stuck a bit when trying to get them out.
Replaced the pcv and oil 500 miles back. There was a bit of oil around the pcv and took members advice on changing for the low price. At the same time I cleaned all the plugs and wires.
So 500 miles later, a little oil that was getting sprayed about is no longer there. PCV valve is clean. Oil is still as clean as it was 500 miles ago. Car runs smooth. Gas mileage is great. No white smoke.
Checked the plugs last night. No more oil. Wouldn't think a $10 part would make that much difference, but I am hoping.
Hoping it is just the pcv valve
kamesama980
Member
- :
- 2002 Protege5
Yes, yes it can. As you found out.
FYI blow by is in the opposite direction north42g mentioned: it's combustion cylinder air that gets blown past the rings to the crank case. what he mentioned doesn't happen the way he's describing. oil going past the rings is just ring-leakage and is caused by bad rings. A clogged PCV and pressurized crankcase is certainly bad but will generally cause gasket leaks and blow seals out before it pushes enough oil past the rings to cause liquid residue or oil-burnnig problems. what the OP has is too much flow through the crankcase vent, liquid oil is being carried out rather than precipitating out of the crankcase air. Same thing can happen if he CC is overpressurized, it causes the high flow through the vent into the intake manifold.
FYI blow by is in the opposite direction north42g mentioned: it's combustion cylinder air that gets blown past the rings to the crank case. what he mentioned doesn't happen the way he's describing. oil going past the rings is just ring-leakage and is caused by bad rings. A clogged PCV and pressurized crankcase is certainly bad but will generally cause gasket leaks and blow seals out before it pushes enough oil past the rings to cause liquid residue or oil-burnnig problems. what the OP has is too much flow through the crankcase vent, liquid oil is being carried out rather than precipitating out of the crankcase air. Same thing can happen if he CC is overpressurized, it causes the high flow through the vent into the intake manifold.
Thanks a bunch! A bit over my head. Help?
Having trouble with the chicken before the egg thing.
Like I said, there was some oil in the combustion chamber. None whatsoever now outside of needing to cleaning it out.
Looking to take off the valve cover, replacing the gasket, spark plugs, and cleaning everything out.
My big question-do you think that there has been any damage done to the engine?
Car is no longer leaking. Oil is very clean. Runs great.
I burnt 1 1/2 quarts of oil over-roughly-over 5k miles before the maintanance I did.
Should I be concerned at this point? Don't have the money to take it in. Don't have a trusted mechanic.
Do you think I caught the situation in time, or has damage already be done?
Thanks.
Having trouble with the chicken before the egg thing.
Like I said, there was some oil in the combustion chamber. None whatsoever now outside of needing to cleaning it out.
Looking to take off the valve cover, replacing the gasket, spark plugs, and cleaning everything out.
My big question-do you think that there has been any damage done to the engine?
Car is no longer leaking. Oil is very clean. Runs great.
I burnt 1 1/2 quarts of oil over-roughly-over 5k miles before the maintanance I did.
Should I be concerned at this point? Don't have the money to take it in. Don't have a trusted mechanic.
Do you think I caught the situation in time, or has damage already be done?
Thanks.
I don't think oil will really "damage" anything, maybe just gum things up a bit. You could have fouled things up from the cylinders to the tailpipe, like the cat's, O2 sensors and pistons themselves but if it were me I'd just put 1/2 a bottle of seafoam in the gas when you fill it up (yea here I go again with the seafoam) and it should really help dissolve and burn off any deposits and leave the car running great. Maybe put the second half in the gas at the following fill-up.
Some guys burn oil all the time and just get used to filling it up when putting gas in it. Just think of it as a two-stroke where you mix the oil in the gas. Our cars eventually mix the oil in for us so we don't have to measure,... it self lubricates the exhaust system.
If your valve cover isn't leaking, there really is no need to remove it. Removing the cover doesn't give much better access to the spark plug holes,... you'd need to remove the head to get right in there. I'd just pull the plug wires and spray some wd-40 or varsol in the holes (with the old plugs still in) to dissolve the oil the blow them out before installing the new plugs. There would be nothing to clean under the valve cover, It's supposed to be all oily under there.
Ohh, by the way, are you thinking that replacing your PCV is what made all the difference?? Does that mean 1 1/2 quarts of oil was getting sucked through your PCV valve every 5k miles? I had no idea it could be that much.
Some guys burn oil all the time and just get used to filling it up when putting gas in it. Just think of it as a two-stroke where you mix the oil in the gas. Our cars eventually mix the oil in for us so we don't have to measure,... it self lubricates the exhaust system.
If your valve cover isn't leaking, there really is no need to remove it. Removing the cover doesn't give much better access to the spark plug holes,... you'd need to remove the head to get right in there. I'd just pull the plug wires and spray some wd-40 or varsol in the holes (with the old plugs still in) to dissolve the oil the blow them out before installing the new plugs. There would be nothing to clean under the valve cover, It's supposed to be all oily under there.
Ohh, by the way, are you thinking that replacing your PCV is what made all the difference?? Does that mean 1 1/2 quarts of oil was getting sucked through your PCV valve every 5k miles? I had no idea it could be that much.
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I stand corrected. I had it backwards. Thank You. A clogged PCV Valve will likely not cause Blow-by into the crank case. I suppose it could happen in extreme cases. kamesama980 is correct to say that a clogged PCV will likely cause seals & gaskets to leak prematurely.Yes, yes it can. As you found out.
FYI blow by is in the opposite direction north42g mentioned: it's combustion cylinder air that gets blown past the rings to the crank case. what he mentioned doesn't happen the way he's describing. oil going past the rings is just ring-leakage and is caused by bad rings. A clogged PCV and pressurized crankcase is certainly bad but will generally cause gasket leaks and blow seals out before it pushes enough oil past the rings to cause liquid residue or oil-burnnig problems. what the OP has is too much flow through the crankcase vent, liquid oil is being carried out rather than precipitating out of the crankcase air. Same thing can happen if he CC is overpressurized, it causes the high flow through the vent into the intake manifold.
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