Not open for further replies.
Apr 3, 2006
Went to by a pcv for my Toyota V8, at the dealer. The manual says to clean and/or replace, and in another schedule for service it says replace. Found out that the dealer has never stocked one, ever and a mechanic said he has never replaced one on the V8. Interesting.
I wonder if the dealer does a free PCV valve replacement. My Ford says at 60,000 miles they will. Good thing too because it's a motorhome and the PCV costs $46!
Very few manufacturers mention anything about replacing the PCV valve anymore, even more so than fuel filters. Both parts are slowly but surely becoming "life of the car" parts.
If it clicks when shaken and your mileage is good, I guess leave it. I just replaced mine on my 2001 Civic and the case is metal. It seems highly unlikely that it would ever go bad, but we're weird around here like that.

Originally posted by Chris Meutsch:
If it clicks when shaken and your mileage is good, I guess leave it.

Just because it still rattles doesn't mean it's working correctly. I just replaced the PVC valve for the 1st time on my '89 V6 Toyota truck. All the leaks I was trying to get Auto-Rx to fix stopped immediatly.
Just because dealer doesn't stock it /dealer mechanics don't replace it doesn't necessary infer that it will stay functional as intended (esp. when you have accumulated lots of mile and/or your motor oil suffers from extreme operational conditions).

I gave my local nissan dealer/mechanics **** for not replacing PCV valves (they claimed that they never replaced any PCV valves when I approached the parts counter for one...) and when I spoke to one of the provincially certified mechanics he said that about 30% of the air-care (emissions) failure esp. borderline case are due to bad/faulty/questionable PCV valves...go figure.

since the inception of PCV venting in the late 60s (started in California, the state of smog), many mechanical issues associated to PCV has to do with the PCV valve itself (be it the metered orifice type or the rattle type). Practicing regular PCV valve cleaning and replacment can pretty much eliminates all PCV related issues and more.. (passing air care like a charm)

Originally posted by Chris Meutsch:
If it clicks when shaken and your mileage is good,

The shake test is almost totally worthless IMO.

Usually idle quality is the 1st hint your PCV valve has problems.

The PCV valve is probably one of the most overlooked parts on higher mileage motors from what I have seen.

I had a PCV valve on Toyotas last 120,000+ miles before they failed I have seen them fail between 70,000 and 120,000 miles on many vehicles including Toyotas. Had aftermarket ones fail in as little as 5K miles. How long they last depends on the original quality of PCV.
Please do fill me in on PCV's. I always thought if they didn't make sound, they were stuck and that was that. I didn't know they could be bad but still seem to function according to my ear.....
Years ago we put pcv valves on a flow bench, all the same brand new valve. Not one, matched the flow of any other one. They were not even close. I wonder how much that effects the way an engine runs.
PCV valvs should be checked/replaced at every tune-up. They can be cleaned with carb cleaner if there's not too much crud inside. A plugged PCV valve can cause a buildup of crankcase pressure which can cause oil leaks. Also when replacing, use OEM.
You should be able to suck air through the valve from the vac side of the valve, but not blow air through it from the vac side. If those conditions are true, the check valve is seating/sealing fine. A PCV valve is nothing more than a flow metered check valve. You see more engines now without a replaceable PCV valve. GM ecotec thru 4.2L is one example. The vortec 4.2L has a hose plumbed directly from the top of the engine block, to the intake manifold for it's suction side of the PCV system. No valve. Just an orifice in the top of the block skirt.

I've seen very few over 100K that still function 100% if you look at the valve, grommet sealing and hose itself. The engine heat just toasts the latter two. The blow test is good for the valve and looking at the portion of the hood for oil and or more dirt over the pcv shows whether the seal/ grommet is still working.
I had to special order one for my Toyota Tacoma through the dealer... cost me less than $10 ... I just replaced mine at 30k miles and I can definately tell a difference in the way the engine runs/idles... I also replaced the spark plugs at the same time...
Just got my 2001 Civic back from major preventative maintenance and it definitely idles better and the throttle response seems to be better. Thanks new PCV!
I'm a fan of regular replacement of PCV valves. For my GM 5.3L, the PCV runs $2.69 at Advance Auto & takes about 30 seconds to replace.

Replacement at the end of the winter drivng season, for those located in the northern regions, makes the most sense to me.

If the plunger in the PCV valve is not sliding freely, it may not be restricting crankcase air flow during low rpm & too much crankcase airflow may cause rough idle.
I personally believe a lot of the Chrysler 2.7L V6 engine sludge problems could have been eliminated with more careful maintenance of the PCV system. All the 2.7L sludgers that we've torn apart all had completely plugged PCV valves. The ones that run good and are relatively clean inside have good flowing valves.

On a '02 Stratus that we have at the shop right now, I noticed the PCV tube going from the valve cover to the plenum is made of metal, and has what appears to be some sort of heating element in it. There's two wires going to this tube, but without taking it apart, I can't say for sure that's what it is.
Heh. Nissan makes 'em very difficult to get to--on the 2.4 and 3.5 they're underneath the exhaust header, meaning you need to remove the header to get at 'em. It cost me almost $200 to replace the one on the 2.4, and the Infiniti dealer basically refused to do the work ("It'll cost ya' around $500 and we've never had to replace one before.")

I love the performance of these engines, but the PCV placement is the pits.
Some PCV valves have bypass holes, and can't be tested by the blow/suck method.
Normally, you can clean them. Some have an internal spring that can get weak, and cleaning won't help this.
Not open for further replies.