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The new gasket that Cummins sent me is in the middle, the old gaskets that I removed flank it. The old gaskets are very thin and flexible, so much so that they've taken the shape of the end the heat exchanger. The new one is just a thick black rubber disc which seems better really. Thoughts or concerns about the vast difference in the old and new gaskets?

The removed end caps. I had planned on replacing them but they seemed pretty solid, so I sanded the heck out of them , primed them and then used Cummins engine paint on them.

Cummins has upgraded a lot of their gaskets over the years. I had a spare set of end cap gaskets in my original (1989) cruise kit and when I cleaned both heat exchangers a few years ago bought new gaskets from Cummins rather than use the old spares....the new ones looked like your black ones and I agree look to be of better quality. Another gasket they upgraded is the exhaust manifold to turbo gasket...the originals leaked - actually sort of weeped - after a couple thousand hours and I had Cummins Mid South come out and change them. Walter, the super mechanic said the new gasket was designed to eliminate the "weep" and it did.

UV

Thanks for your thoughts. I'm having a hell of a time getting my pencil zinc out. I've doused it w/ CX inside an out and haven't managed to budge it. Did a good job of stripping the head though...

steve
you probably know by now that the pencil zincs should be change out every year, i have 4 on each of my engines. mine last all year, mike o has to change his maybe twice a year depending on the electrosis in the water

also after there out take small wire brush and clean the threads up, put a dab of never seize on the thread and you good to go

The flimsy ones are standard Sendure gaskets, just like the ones on my Chryslers.

I checked both zincs after my first year and they were like new, which made me complacent. The one I can see is still not that bad it's just really locked in there. Worth changing them out annually if only to avoid this situation.[/i]

I'm sure you know to put an open end wrench on the nut brazed to the heat x shell then you can put some ooooomph on the zinc....try an impact wrench on it, maybe jolt it loose.

UV

Sometimes the zincs will swell as the corrode and won't fit back through the hole. The bronze plug just unscrews off of the zinc. You have to remove the endcap to get them out. Use a smaller zinc if you have this problem.