Valve cover grommets

[eaglescout526]

So I bought a valve cover grommet a couple years ago to replace the one I have for a better seal than the chewed up one. I got it in and its the toughest thing ever. I've revisited installing it a couple different times and the ideas have failed. Tried one time with a flat head to push it on. Poked a hole through the VC. Tried another time by boiling it, didnt soften. Tired tonight with just motor oil to slip it into place and no dice. Wondering what you guys have done if yall have ever had to replace it or any ideas at all really. here's a couple pics to show what I'm talking about:

 

 

Now keep in mind, the 2.5L VC is plastic and the 4.0L is metal. I can understand the ease of installing it on the metal cover but not the plastic and thats where I am lost on installing the grommet. Theres gotta be some way those dealer techs did it to the plastic covers. Although I do appreciate the suggestion, I will not go to a later 2.5L metal VC with my set up.

[Minuit]

Put the valve cover in the oven (at a non-melty temperature) and the grommet in the freezer to make thermal expansion work in your favor?

 

Copious use of lube?

 

If motor oil doesn't work, maybe try some silicone grease?

 

Normally some combination of the two works for me.

[eaglescout526]

Oven isnt a bad idea and I wouldve never thought to use the freezer on the grommet. Ill have to give those a spin.

[eaglescout526]

*update on this*

So I needed to do a tune up today, gas mileage was bad, new sparkplugs, oil change and a VC gasket. I experimented a few days before and used Minuits idea of heat but to the grommet and not the valve cover. Oil as lube didn't work and neither did freezing because the grommet is as hard as a rock. Used a torch, heated up the grommet and viola I was able to get the new grommet on with a screw driver and gently pushed the lip in and down to sit in the cover. Now to retire the 30 year old original grommet. 

[cruiser54]

Silicone spray.