How often are you guys changing your PCV Valve in the 3.5 EB? Is there only one? I always did it at 30k in my other vehicle. I'm at 28.5k and figured I'd inquire.

Would it be wise to change the rear diff fluid at 30k as well? I did it at 30k then every 60k thereafter for my diffs and transfer case in my G37.

 

I've never proactively replaced it. Only when a code showed up

 

PCV and rear diff at 30K? That's serious overkill. If it makes you feel better, do the PCV at 100K. Ford says the diffs are lubed for life... do them every 60K if you want to be really picky.

 

Well PCV is cheap so why not? I figured initial change at 30k for break-in wear that occurs.

 

There are lots of things on a vehicle that are cheap. Doesn't mean you should tear them off at ludicrously short intervals and toss them in a landfill. My family has quite a history with Ford engines, running 5.0s, 5.4s, 3.5s all over 200K. We've never replaced a PCV.

If you're concerned about longevity, pick a quality motor oil and change it at a reasonable interval.

 

I also don't think there's a reason to replace the PCV valve unless it's defective. Not sure how it's constructed on our 3.5EBs, but they're supposed to last the life of the engine.