Valve cover inner liner separation.

[SlimPickins]

I'm doing all the basic catch-up maintenance on my new-to-me Gen 2.5 including the spark plugs and valve cover gaskets. I removed the valve covers fully expecting to simply clean them up and reuse but low and behold... The inner liner had separated from the body around the spark plug opening which would seem to at least render the rubber spark plug tube seal ineffective. Had I been in a hurry, I may not have noticed this right off the bat so I figured I'd pass this on. Perhaps this is a known issue (a cursory search came up empty) but I'm hoping to spare my fellow noobs a headache.

 

[normal_dave]

My vote is get a ball peen hammer and a straight edge, flatten that hump out put them back in service. I think the tube seal may not interfere with the inner liner, you could re-check the diameter and fit. Edit: another thought, maybe during a prior service, someone was a little to aggressive with the screwdriver digging out a tube seal and bent the liner up, the liner isn't oil tight anyway, it's just a baffle, and you have an oil fill on one side, as well as a breather opening and the pcv connection as well.

Looking at your pictures, I'd also suggest taking your pliers and gently work around the gasket mounting channel on the valve cover pinching and straightening the inner liner toward the outer valve cover perimeter. Once everything is clean and dry, apply a reasonable bead of RTV to the valve cover side of the (hopefully new Mitsu OEM gasket), and when you put the cover back on use your 1/4" drive ratchet and tighten them just past "finger tight" if turning the extension/socket only by hand with a decent grip/torque, then maybe another 1/4 turn with the ratchet and stop before you think you're done, and that should be good.

There is a torque spec on the valve cover bolts, which proved useless to me, but as soon as you have them what you think is "snug", they are already too tight and they will leak, (said in my best Fatherly voice of experience). After I removed my freshly serviced leaking valve covers and made the above repairs, the new gasket actually extended a fair bit past the bottom of the valve cover all the way around, and by the time I oh so carefully tightened the bolts it nested and still sat in such a way as to slightly hold the cover off of the head. I was greatly relieved to find no leaks and still today, high and dry.

The secret was pinching the liner back into parallel and as close to the valve cover perimeter as possible, all the way around, along with the proper use of the RTV inside the cover.

Others may chime in with better advice, but this worked for me, and hopefully I have spelled it out in a way that is understandable.

"Good Luck Jim, this tape will self destruct in 5 seconds..."

 

[SlimPickins]

Excellent advice, thanks for the clear explanation. I did end up getting a new valve cover altogether as I wasn't sure if rehabbing it would work out. Sounds like I could have done just that. The gaskets were replaced and the covers torqued to spec per the FSM. I did not put any RTV inside the cover as the covers were on a couple of weeks before I posted these pics... Fingers crossed as they say. I'd rather not have to take everything off for a redo. Thanks again for the 'fatherly' advice normal_dave, hope mine stay 'high and dry' as well!

 

[normal_dave]

Great News,

I've read (maybe here or the Aussie forum) that the original design engineer on the Mitsu valve covers was "the evil one" his self...or some one of similar depraved nature.