Pcv
Pcv
12-11-2003, 02:51 PM
#2
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In the old days, the "Positive Crankcase Ventilation" system just vented to the air. Ever seen old photos of the freeways and they all had the dark black stripe down the middle? That was in a large part due to PCV oil vapors.
Now days, that oil vapor is vented off, then drawn into the intake where it both lubricates the upper engine and where it is burned off, rather than being dumped into the air and on the roads.
According the Toyota service specs I am looking at, it should be swapped out every 30k miles. It's a funny beast, basically a one way valve. It can last the life of an engine, but when it plugs up, pressure builds up in the crankcase and seals start to get upset.
Don't panic if you have never changed it, odds are good it's working fine. But put it on your list of things to do next tune up.
Now days, that oil vapor is vented off, then drawn into the intake where it both lubricates the upper engine and where it is burned off, rather than being dumped into the air and on the roads.
According the Toyota service specs I am looking at, it should be swapped out every 30k miles. It's a funny beast, basically a one way valve. It can last the life of an engine, but when it plugs up, pressure builds up in the crankcase and seals start to get upset.
Don't panic if you have never changed it, odds are good it's working fine. But put it on your list of things to do next tune up.
12-13-2003, 06:04 AM
#4
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The most trouble you'll have, besides the possibility of it clogging is the longer you let it go, the more likely the plastic piece on top will deteriorate and come apart when you pull it. Just don't let the pieces fall into the engine if it does.
12-13-2003, 09:15 PM
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If you have doubts of when it might have been changed, just change it... along with the rubber tube that attaches to it as the old one has probably lost its elasticity due to heat. New one will guarrantee a better seal.
The PCV valve on my truck was clogged and created a mess. Since it couldn't vent the gases out of the crankcase, they were forced past the piston rings along with oil. So...I had an oil burning problem (really bad on long trips...1 qrt per 1000 miles), a low oil problem and a carbon buildup throughout because of these two things. All because of a $6 valve that the dealer never bothered to check during a major service (how do you tune an engine PROPERLY with a bad PCV valve?).
The PCV valve on my truck was clogged and created a mess. Since it couldn't vent the gases out of the crankcase, they were forced past the piston rings along with oil. So...I had an oil burning problem (really bad on long trips...1 qrt per 1000 miles), a low oil problem and a carbon buildup throughout because of these two things. All because of a $6 valve that the dealer never bothered to check during a major service (how do you tune an engine PROPERLY with a bad PCV valve?).
12-14-2003, 07:24 AM
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FYI, Receipt is on my desk:
Valve: 12204-65010
Grommet: 90480-18001
-Stu.
edit: for a 97 3.4 4R, I just looked at your avatar.
Valve: 12204-65010
Grommet: 90480-18001
-Stu.
edit: for a 97 3.4 4R, I just looked at your avatar.
Last edited by hungryStu; 12-14-2003 at 07:25 AM.
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