PCV valve - Change interval and reasoning?

[LDB]

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?

Twice a year so I have my summer PCV and winter PCV at the appropriate times.

 

[ARCOgraphite]

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.

My 2007 Silverado 4x4 pcv was glued into the rocker cover. No anti-backfire slug in that one either, That was the old gen SBC based vortec v6. with the spider multiport - I think

I was looking for a vacuum leak and eventually found it in the TB being not fastened down to the (plastic) intake (!) Nice job GM. trying to keep up with Ford?

Good memories of having a bench seat, no center console garbage, and a shift it yourself 5-speed with a long lever. That thing spilled B body vibes all day.

 

[CBR.worm]

On my cars, I typically do it ~ every 80K, or if the valve covers have to come off for some reason. I worked in a garage in the late '80s for a bit. It seems like we spent a lot of time cleaning or replacing PCV hoses that had filled with gunk to the point of restricting flow. That, and oil-soaked breather sponges in the carb lower lid or housing used to make me sweat.

 

[Nesterenko]

Don't they throw codes? If so just wait for one.

 

[1444buicking]

Do not always throw codes, unfortunately.