Aabout 1.5 years ago my pcv cracked and caused a check engine light (lean code). I replaced it with an OEM one from dealer, then around 7 months later i noticed it leaking oil in the same spot and it too had cracked. Replaced it again and around 8 months later i noticed oil there again and replaced, cracked! Just replaced it for the fourth time today. What could be causing this? They were cracked in this same location. So im guessing high crankcase pressure and blow off. My possible thoughts would be old intake filter. Bought the car with an Inject aftermarket cone filter and drive it for 6 years, maybe lack of intake flow backing up pcv system? Or worn motor mounts which my car has, although I don't feel it. I will also be installing a catch can. I just hope its not worn pistons or anything internal like that. Has anyone had this issue before?

 

Could it be you over torqued the two fasteners?
It is cheap plastic after all

 

I dont think so. I tighten it normally by hand, and when I removed the old ones there was never any cracking near where the bolts go in. Im thinking there may be an issue the EGR valve? Its pretty oily back there, but im not getting any codes atm. Maybe an issue with that is causing high crankcase pressure, causing the PCV to break?

 

You are talking about this crack in the main body of the PCV?

• It's not possible you have enough crankcase pressure to crack the plastic housing, the driver's side cam cover is open to the intake tube so pressure would never build up.
• Motor mounts are not possible, the PCV assembly moves with the engine as a whole. Bad motor mounts would only crack something that's mounted to the engine at one side, and the body on the other (air duct tube, for example).
• Worn pistons would cause excessive blowby, but again that would be vented out the other PCV breather.

I'm with Wingrider, either the screws are being torqued too tight or there's some defect in your cam cover that is putting strain on the plastic. I imagine the latter is hard to believe if the original PCV lasted 20-something years. The screws on these PCV need basically no torque. I'm talking like 5 in lbs. Once they are flush with the plastic, the o-rings do all the sealing. The screws just keep the valve from vibrating out. You get no additional sealing from torqueing them.

Are you certain that crack is actually a crack and not just some moulding flack? (I thought I had saved my old PCV to take a look, but it got tossed in the trash). I would bet on the o-rings leaking oil and air being 100x more likely than the plastic failing 4x in a row. Especially on o-rings that are 10+ years old and have been sitting on a dealer shelf.

 

UPDATE: 18 days after putting in a new PCV valve (4th one so far) I notice oil leaking out around it. The valve was not broken this time, seemed a bit loose though, it looks like it wasn't forming a good seal. I am going to get new O rings for it to ensure a snugger fit. Mind you first replacement PCV was from Jag dealer, second was a $40 OEM marketed amazon purchase, then the cheap $20 amazon one, this is the more expensive $45 dollar one, I have noticed difference in quality and fit among these PCV valves. The Jag dealer one seems very cheap