PCV valve replacement – which thread sealant?

[Peter]

Hello all,

I’m working on my dodge stratus again. It’s time to replace the PCV valve again, and I’m unsure what thread sealant to use. If I use no thread sealent, the valve leaks at the threads. I have this permatex product:

http://www.amazon.com/gp/product/B000HBNTGY/ref=pd_lpo_sbs_dp_ss_3?pf_rd_p=1944687642&pf_rd_s=lpo-top-stripe-1&pf_rd_t=201&pf_rd_i=B000HBM72Q&pf_rd_m=ATVPDKIKX0DER&pf_rd_r=0JM2TC2WWTWSHX7GSKZ7

This works well on metal, but the MTSD states that it is not recommended for use on plastic. Both my PCV valve and the valve cover it needs to be installed into are both plastic. I would use teflon tape, but I don’t want to take the chance that excess might be pulled into the head/tangled in a cam shaft if it starts to break down. Should I take the chance and use my permatex sealer anyway? I can’t find anywhere else that sells a sealant that is both safe for plastic and rated for use around oil.

Thoughts?

Thank you!

Topic

[Mike]

I think the general rule of thumb is that plastic threads don’t use lubricant or sealer, especially when screwing plastic into plastic. They are, to a certain extent, self-lubricating and self-sealing. Adding stuff to the threads makes them much easier to strip, and plastic threads are easy enough to strip as it is.

In your case, perhaps you’re missing a sealing washer or somesuch for the PCV valve. Or maybe the threads in your valve cover are damaged, in which case the best fix would be to replace the cover. If you really do need to seal the threaded plastic joint, teflon tape would be about the only thing I’d consider using in this application.

[Peter]

I’ve replaced the valve cover 3 times. Once because I cracked the valve cover when replacing the pcv valve (I over-tightened the valve and caused the valve cover to crack (and the crack kept growing and causing leaks/problems). Before I over tightened it, I had it installed at the right torque spec and it leaked slowly at the threads (which were not damaged). I replaced that one with a used valve cover/new gaskets. That new cover also failed in the same way (after replacing the pcv valve). After all of this, I bought a new, factory valve cover with preinstalled pcv. The pcv on the new factory unit was sealed with some kind of liquid sealer (which looks a lot like the permatex stuff I have). The FSM also says to use a liquid sealer, but the product they reference is no longer produced…

So, I know I need a sealer, but I’m still not sure what to use.

[Peter]

Ok, had an idea and I called permatex. I left a message and they got back to me a few hours later. They let me know that the product that I posted above is safe to use on plastic components. Problem solved! 🙂

Thank you for your opinions though!

[Author]

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