Donaldbabineau

I replaced the PCV on my 71 cutlass supreme and noticed the grommet was able to slide/rotate a little on the valve cover. The PCV fits snug in the grommet. I was able to rotate the grommet till it seemed to fit snug on the valve cover, but I doubt it is sealed. Considering the PCV is connected to the carb, will a grommet that is not completely sealed create a vacuum leak? If so, what can be done short of replacing the grommet. Do I need to remove the valve cover to replace it?

oldcutlass

Use some black weatherstip adhesive in the groove that meets the valve cover. Once dry it will not move or leak.

Donaldbabineau

should the grommet be hard plastic? Mine is and may be so from age. My concern is I may not be able to remove the grommet without breaking it to apply the adhesive. To remove the grommet, do I pry it off with a flat screwdriver? If I can't remove the grommet, I suppose I could flatten a thin bead around the crack, but I haven't worked with that material before.

joe_padavano

The crankcase is vented to atmosphere anyway. This isn't going to cause a vacuum leak.

Donaldbabineau

okay Joe, I thought what you are saying might be the case. But for my understanding, how does an unsealed fitting connected to a very large port in the carburator not cause a vacuum leak?

joe_padavano

Because the PCV valve has a orifice in it that restricts flow, and the carb is calibrated to account for that flow. If you pull the PCV valve completely out of the grommet, the engine still runs with no changes.

Donaldbabineau

Good to know. Glad I don't have to mess with it.

69HO43

You may not have to, at least not from a vacuum leak standpoint. However, if the material gets too loose in the hole or starts to deteriorate further, you could get an oil seepage where the grommet goes into the cover. Not saying you will, it's just something that might show up down the road. Then you can just replace it. Taking it out to seal it with sealant is kind of a no-win situation since you'd be taking it out anyway. Why not pop a new one in if you go that far?

Usually, if they're still pliable, you can squeeze the pee out of them, or a plastic trim removal tool to get a corner lifted to be able to leverage it out of the hole. Be careful not to go crazy and tear it up or you could get little rubber bits in the head. It may or may not be an issue in the big picture, but I don't like foreign particles in the oil system. I probably wouldn't do it now if it's not leaking oil.

Donaldbabineau

yeah it's probably taken 51 years to get to the point it's at. No oil is leaking.