PCV valve - Change interval and reasoning?

[SC Maintenance]

Their is no change interval on the manual for my Nissan's PCV valve. I have dutifully changed it every 50K miles based on advice from a Nissan forum. Every time it comes out looking perfect. These engines have no sludge - you can see under the valve covers in the oldest one in my signature. Changing isn't hard if you have the correct tools - but its on the back of the engine so getting the hose off can be a pain for the uninitiated.

The PCV valve on my Toyota is underneath the intake manifold. It doesn't look too difficult - everything comes off in one piece, the Toyota boards indicate people having dealers recommend replacement at a cost of around $500. While I am sure I could do it no problem, the idea of removing an intake from the cylinder head sounds like an opportunity to break something else in the process.

So how often do you change your PCV valve? What is the theory / logic about when or why? If there not getting gummed up does it matter? Does anyone bother cleaning and re-install?

 

[Patman]

I haven’t changed a PCV valve on any of my cars since the 90s. My Civic has 164,000 miles on it on the original PCV. It’s relatively easy to change but it just isn’t something that has been on my radar in a long time.

I personally feel, and I may be wrong, that PCV valves don’t really clog up anymore if you are always using good quality synthetic oils.

 

[rijndael]

that PCV valves don’t really clog up anymore if you are always using good quality synthetic oils.

I also think we're much better than we had it in the 80s and 90s, but on engines like the GM 1.4, there are still issues.

 

[ARCOgraphite]

Their is no change interval on the manual for my Nissan's PCV valve. ... ... .

So how often do you change your PCV valve? What is the theory / logic about when or why? If there not getting gummed up does it matter? Does anyone bother cleaning and re-install?

Never had an issue on a modern engine. If a used/abused car I'll run some fuel/oil mix down the vacuum side plumbing there to "possibly" de-gum the metering/ anti-backfire pill - especially if it is hard to reach.

Did one on a Subaru EJ on a 2011 Outback (64k miles) a few years ago. Waste of time, the old part was fine. The factory hose clamps on those are terribly fiddly.
Some Turbo /advanced engine have a complicated vapor recovery system and I would go by the book with those. I never had the 'pleasure' to work on one that was complex.

 

[Kira]

Driving conditions likely play into this.
What's a vehicle's particular moisture / burn-off characteristics?
Ambient temperatures vis' condensation.
It must be affected by trip length and even contours of the system itself (drops settling to a low point then becoming goop over time).

I also thought the thin wire spring inside many PCV valves has to react with acids and fail with time.

Also, any hoses to and from a PCV valve can go brittle.

 

[ARCOgraphite]

Driving conditions likely play into this.
What's a vehicle's particular moisture / burn-off characteristics?
Ambient temperatures vis' condensation.
It must be affected by trip length and even contours of the system itself (drops settling to a low point then becoming goop over time).

I also thought the thin wire spring inside many PCV valves has to react with acids and fail with time.

Also, any hoses to and from a PCV valve can go brittle.

Good advice.
Extreme cold starts and sub-zero shutdowns can really gum and gel things up. Surely anything over 10y/100k miles likely need service or a least a thorough going over.

My wife had a newish Honda that loved to make a Flan under the fill cap and a Frappe' in PCV hoses.

 

[tnt_motorsports]

I changed the PCV on the wife's T&C when I was in there doing the oil cooler last spring. Van had ~95K on it. It probably didn't need changed, but I had the OEM replacement and all the parts off to get it done.

Just my $0.02

 

[Lubener]

The change interval on my vehicles is 60k. Some say if it rattles it's ok. There is a spring inside the valve that can weaken and affect its operation.

 

[iCurious]

Changing the PCV Valve is subjective. Each engine is different due to engine size or configuration. If it's prone to clog up, you will need to replace it much often.

What we know is: the purpose of the PCV valve is to help alleviate the pressure accumulation in the crankcase. If it gets clogged, there will be excessive buildup and it will cause oil leak. Some same it can also cause oil consumption.

Since there is no interval in the maintenance book. Change as often or not often as you like. However, if it does becomes clogged, it will become an issue.

In this case, people with the same vehicle with same engine size should converse and figure out the appropriate interval.

Besides, if it's easy to change and cheap, consider it a cheap maintenance to maintain.

For me, I think it's reasonable to change it at least once before it hits 100k miles.

 

[jhellwig]

LS engines at one point had no moving parts in the pcv “valve”. It was just an orifice that looked like the older pcv valves. Don’t know if they still do or not.

There used to be a breather vent filter also on several vehicles in the 80s.

 

[1444buicking]

Some recent engines have serious issues with the PCV valve (or similar). Our fleet includes:

- 2013 Toyota 2.5L (Camry). Traditional PCV that clogs up. Popular complaints include excessive oil consumption.
==> PCV valve is very difficult to access and remove, even using "shortcuts".

- 2013 GM 2.4L (Terrain, Malibu, LaCrosse) had a PCV orifice that clogs with carbon. Popular complaints include: excessive oil consumption, blown rear main seals, poor performance).
===> PCV valve killed a lot of engines via oil consumption (killing timing chains) or blowing oil out on the road via rear main seal

- 2009 GM 1.8L and similar (Cruze, Astra, etc) had a rubber PCV flap that rips. Popular complaints include: poor performance, MAF codes)
===> Easy fix but need to buy a new valve cover and gasket so expensive.

 

[Paco Pena]

I have never replaced one but cleaner many. A shot of carb cleaner or brake cleaner will un-gum one. If it rattles its good enough for me.

Paco

 

[ejes]

I change mine at 100k unless the engine gives me a reason to do it sooner. Reasoning is because you can't really tell if they are good or bad. Don't trust the rattle test. Some designs rattle when they are good, and some don't just as some rattle when they are bad and some don't. The designs are not consistent across the board. They are cheap (usually) and easy to replace (usually). A bad one can cause several easily avoidable issues like oil consumption,, sludge, and exacerbate oil leaks. A lot of gunky gases pass through those little things. $10- 20 for a fresh one seems to make a lot of sense.

 

[Kira]

For the Ford 4.0l Cologne engine (SOHC), a guru on the Ranger forum advises changing the PCV valve every 3rd Winter in northern US climates and every 4th in Southern.

 

[rszappa1]

I have never replaced one but cleaner many. A shot of carb cleaner or brake cleaner will un-gum one. If it rattles its good enough for me.

Paco

also check the rubber tube connected to the PCV valve... It build up a lot of gunk....Just remove and clean out with brake clean....

 

[FCD]

I've changed the Pcv on my 75 Capri once in its entire life, it takes a minute since it's right on the valve cover, and this engine has probably close to 180k miles on it, running on conventional modt of its life, every once in a while i take it out and shake it to check and put it back in , i changed the rubber tube aswell just because it was so old it was rock hard and cracking.

 

[ka9mnx]

Way back in the old days we used to change the PCV, fuel filter and air filter the same time the plugs were changed, Then it became 100k miles. My feeling if it's clean under the valve cover the PCV is probably good pending the rattle can check,

 

[STW]

Their is no change interval on the manual for my Nissan's PCV valve. I have dutifully changed it every 50K miles based on advice from a Nissan forum. Every time it comes out looking perfect. These engines have no sludge - you can see under the valve covers in the oldest one in my signature. Changing isn't hard if you have the correct tools - but its on the back of the engine so getting the hose off can be a pain for the uninitiated.

The PCV valve on my Toyota is underneath the intake manifold. It doesn't look too difficult - everything comes off in one piece, the Toyota boards indicate people having dealers recommend replacement at a cost of around $500. While I am sure I could do it no problem, the idea of removing an intake from the cylinder head sounds like an opportunity to break something else in the process.

So how often do you change your PCV valve? What is the theory / logic about when or why? If there not getting gummed up does it matter? Does anyone bother cleaning and re-install?

Replaced one on 2006 Honda pilot with 258K on the clock. It was an original PCV on the engine and there were a few signs that it needed it. Probably could have just cleaned it and replaced but had the replacement handy and put it on the car. Hope to get 100K more out of it.

 

[Mainia]

I check my PVC valves and they are always clean. I spray in one end and the other to a rag. I have also sprayed the tubing too and nothing but a very very small dark brown like varnish comes out. The valve always shakes fine when first taken off. I no longer worry about it on any of may cars after I do the initial cleaning on new buy of a used car. I they not to buy sludged up cars as I always bring a flashlight and check the oil filler port if it is designed were I can see the valvetrain.

 

[zzyzzx]

I am more concerned about the PCV grommet on mine as it is 25 years old, but will probably replace the valve and grommet when I hit 100K miles. I might go ahead and do the grommet and PCV elbow sooner.