Half moon seal alloy replacement part number.

[Growlerbearnz]

Despite Mitsubishi's insistence that it doesn't exist, I've managed to find the part number, order, and fit an alloy half-moon seal to the 4D56T engine in my deli.

Part number MD372348, intended for a Lancer Evo VIII. Apparently it's ok for Delicas to dribble oil, but not Evos.

(I searched on here a bit, but couldn't find the part number. hope this helps someone!)

Cheers!
Grant

[jessef]

Nice find.

The half moon seals and the top cones come as a package with the valve cover gasket in a Mitsu OEM kit.

[Growlerbearnz]

The only kit my Mitsubishi dealer will sell me has a black rubber seal, not the nice permanent aluminium one I found here

[CREGAN]

Can you get this part for a 4m40?

[Growlerbearnz]

No idea, I don't know as much about 4M40s as I know about Astrons. Is there a high-performance petrol version of the basic engine? That engine may have an alloy seal.

Edit: Looks like the 4M40 comes in one flavour. I wonder if the seal I've shown above would fit? I'll measure the diameter once I get home from work and post it here.

[CREGAN]

I am just about to change my Valve Cover Seal on my L400 and if I could get rid of the half moons that would be great. The half moon seems to be a poor design since a lot of leaks seem to come from there.

Craig

[lopar]

Would it be that difficult to have a machinist whip some up from a rubber donor seal?

[jessef]

No. The rubber seal compresses as you press it in. It's a press-fit. A solid material would have to be a hair smaller to be able to slip in with a bead of sealant.

IMO the half moon seal is fine if it's installed properly with a good rtv/gasket sealant. It's the not the half moon area that leaks often. It's the lip that mates with the valve cover gasket. Both are rubber and will shrink over time causing the leak. A bead of sealant across will make the two seals last longer.

[CREGAN]

Mine was replaced about a year ago and I already have to re-do it though. Wouldn't think there would be much shrinkage since then...but

Craig