Hello,

I just noticed the valve cover gasket on my 258 Jeep engine
is leaking again... I put this gasket on 2K miles ago..It's
a cork type...Mc Cord brand.. I glued the gasket to the aluminum valve cover (after market) with Gaskacynch and
let it set for 30 minutes or so before installing the valve
cover... This is the 2nd time a gasket has moved around and started leaking on this engine...

I'm thinking of just using silicone sealer with no gasket.
Has anybody out there tried this on a 258 with an aluminum
VC? We used to do this on SB Chevy's about 100 years ago.

the later plastic covers are worse than the older steel ones, but i've always found 'em leak-prone. too many previous owners (and, erm, me) have overtightened them causing them to warp...

my final working solution was to get it all spotlessly oil-free, and use Permatex brand, "Right Stuff" gasket maker. as far as i know that stuff is unique. unlike silicones etc it's removable like a custom gasket.

my most recent engine was built using Right Stuff, replacing every single gasket except head, oil pump with the stuff. that was 2005, still not leaking. i'm sold.

TANKS

OK, I finally figured out what was going on... My #5 cylinder wall was cracked... Ever so slightly... It allowed tiny amount of coolant to work its way into the crankcase as steam..
#5 spark plug would foul after 3 or 4K miles... No spark plugs available with hotter than stock heat range, so I added a .030" copper washer to the spark plug and that worked.

I finally installed a rebuilt 258.. No more problems with valve cover gaskets.. But, the rebuilder failed to notice a cracked water jacket near the water pump, on the side of the block... And yes I paid to have the block thermal cleaned and then magnafluxed.......

I was not willing to remove the engine for the rebuilder to repair so I drilled and plugged the 1 1/2" long crack..They at least provided the iron screws/plugs and tooling.

The new/balanced 258 runs very smooth.. No extra power, but with stock 1950 brakes...And now double original horsepoawer.. Not a great idea......