PCV valve rattling?

Status
Not open for further replies.
Joined
Oct 11, 2002
Messages
22,183
Location
Colorado Springs
Hmmmm, never heard this one. Was checking my A/C charge the other night with the engine idling, and whenever the compressor kicked off, there was a rattle from the PCV. Confirmed with the mechanics stethescope (ala screwdriver). It is a Fram. Must be busted somehow, like the plunger can't seal flat in there so it's just rattling around. My idle has been a bit rough as of late. Guess I'll try a dealer valve and see if it works.
 
when you shake a PCV is SHOULD rattle. The spring is quite weak so that only a slight pressure in the crankcase or slight vacuum from the manifold will open it.
 
I reluctently ordered one from the dealer. 7 buckeroonies. Oh well, least it's metal. Every other aftermarket one is obviously made by the same manufacturer and they're all plastic.
 
good deal, most of the aftermarket ones run $10. but the innanrds on the plastics ones (the one or two I've taken apart) were metal, just the outer shell was plastic.

The OEM on my 93 camry was plastic as was the replacement I got (for $10), i recently replaced it with 180k+ on the odo. Still seemed to be ok, but I just thought it might be due....
 
$10? Yikes. The Fram I bought was around $3. Once the new one gets here, I'll take the Fram apart and see what the deal is.
 
I replaced the PCV valve in my wife's car with an aftermarket PCV valve and it gave horrible results. Start-ups and idle was rough, plus it began using oil for the first time. I tried a store brand PCV from both Autozone and Advance Auto Parts. Both rattled when you shook them and they were both new...but they both performed horribly.

I bought a $7.50 Motorcraft PCV valve from the Ford Dealership (came with a grommet) and it fixed everything. Start-up and idle are very smooth and oil usage is zero.

If I ever have to replace a PCV valve in another car I will use one from the dealer.
 
quote:

Originally posted by NewGuy:
I replaced the PCV valve in my wife's car with an aftermarket PCV valve and it gave horrible results. Start-ups and idle was rough, plus it began using oil for the first time. I tried a store brand PCV from both Autozone and Advance Auto Parts. Both rattled when you shook them and they were both new...but they both performed horribly.

I bought a $7.50 Motorcraft PCV valve from the Ford Dealership (came with a grommet) and it fixed everything. Start-up and idle are very smooth and oil usage is zero.

If I ever have to replace a PCV valve in another car I will use one from the dealer.


I totally agree with you. The rattle test does not show the entire picture. The OEM PCV valves have solved rough idle problems for me more than once. I no longer waste my money on aftermarket PCV valves. Even if you Lucky and get one that works right they still don't seem to last nearly as long as OEM. A rough idle is a very good sign you may have a problem with PCV valve.
 
Well, I do in fact have a rough idle, so maybe I learned a lesson on this one. I've always thought PCV valves are so insignificant that any cheapo replacment'll do. Guess I'll add PCV to the short list of dealer only parts to buy. For me, this includes wires/cap/rotor, air filters sometimes, and Toyota red coolent.
 
quote:

It's supposed to close shut at idle aka when engine vacuum is high, but it sounds like it's having trouble.

It's supposed to flutter at idle. It basically is a regulated manifold leak. It opens ..bleeds off vacuum ..closes ..a constant cycle at idle. When you're going down the road ..it drafts in parallel with the throttle body and induces proportional flow depending on throttle position. All that it's missing is a throttle butterfly.

This is normal. They also, IIRC, don't truly close. There's supposed to be a curved metal spring (think mini-leaf) at the seating area. It will close upon backfire ..but bleeds some vacuum even when closed. You should be able to test this with your new one by blowing backwards through it.
 
It's rattling with the engine running, not from me shaking it. It's supposed to close shut at idle aka when engine vacuum is high, but it sounds like it's having trouble.
 
Status
Not open for further replies.
Back
Top