The PVC valve on a 1995 Jeep Grand Cherokee ratles?

Answer 1

I assume you are talking about the 4.0L I6. There is always at least a little valve rattle on the AMC inline 6 4.0L engine of all years, even on the later-model engines. This is an inherent feature of the I6 hydraulic valve design. But it's impossible to guage if your valve rattle is serious by reading words in an e-message. If it sounds like just a single valve 'clacking' under the valve cover, you may have a problem and should get it checked out. However, if it sounds like all the valves are tapping a little noisily at idle (like marbles rolling around under your valve cover) it might not be much of a problem. Making sure to use the correct weight motor oil might be good. I use 10W-30 and it works fine on my 1995 (but still has a 'little' clacking at idle). But overall, if it's 'very' noisy (especially at speed) then it would probably be best to take it to a reputable mechanic that is famialiar with the AMC I6 engine and have it checked out.

Answer 2

Could be many things.....Look and listen for any vaccuum leaks around the engine especially up around the fuel injection area. A vaccuum leak will have a high pitch whistling sound. With the engine sucking in extra air at a vaccuum leak this will pull down the engine and affect the RPM's. Run your hands along all of the vaccuum lines to see if you can find a leak. How long since you changed your spark plugs? Most likely it is the Idle Speed Control Valve located in the middle of the engine but on the top surface. If you take off this piece and spray it with Carberator Cleaner 3 to 4 times and let it sit for 15 minutes between sprays it will change things.

Answer 3

It is probably time to replace your positive crankcase vent valve. They are fairly inexpensive and easy to replace. Check for a vacuum leak if it continues after you replace it.

Answer 4

The PVC vavle is supposed to rattle...if it doesn't it means that it is dirty and it either needs cleaning or replacing.