Just replaced PCV Valve. 2012 Acura TL.
The old grommet / seal fell off when uninstalling....couldnt find it.
New valve didnt come with grommet / seal. Tightened new valve, no vacuum leak appears, no check engine lights.
Should I be sure to get the grommet / seal or just leave as is?

Thanks!

 

Might start weeping oil without that seal.

Good idea to keep a kit of O-rings on hand with different sizes.

 

Is the new oem or aftermarket ? I bought oem from acura and it came with the o-rings on it already, didnt have to buy or install separately.
I'd just use a perfectly matched (pressure spec) oem pcv mainly for ideal operation.

 

It was OEM from Honda. I didn't see a separate grommet/gasket...but thinking it was affixed as part of the actual valve (hence I didn't notice it) to me....it's sealed on very well...

 

If you are thinking there should be a grommet/gasket between the valve and the engine body then no there isn't any actually, its just a bare contact so you should be ok. There are just two small O rings on the valve one small one at the tip and a slightly bigger towards the top of the valve. if you have those you are good.
Btw, DO NOT over tighten the valve otherwise the plastic top will break! It has a weird gap its not flush and it will keep bending until the screw keeps turning and eventually break. Just feel the point where its good enough.
do not ask how I know

 

There is a metal sleeve, are you referring to that? The one the bolt goes through.

 

If you purchased an authentic OEM PCV valve from a reputable dealer/OEM parts vendor, then the new valve should have come with a new O-ring and the bolt hole should have a metal grommet to prevent over-tightenting and cracking the plaice valve.. I just did this for my 2012 Acura TL and remember, even after lubricating, the new O-ring, it was still a PITA to get it installed. Tight fit.