Rear freeze plug coolant leak solutions

Well after over a year of dealing with airdog I finally have a working fuel pump so I can actually get the engine running currectly but my billet EatSoot rear freeze plug leaks constantly. Plugging in the block heater makes it leak a stream just from the thermal expansion. I've tried new o-rings I contacted EatSoot and got told I was out of luck for any help from them. Has anyone made their own plate? I was thinking of machining a new one that uses a gasket to the block instead if an oring. It sucks that I bought all the best parts and had problems from every single company backing their parts. Lost all faith in this industry.

I’m running the fleece bypass kit with no issues. Cummins actually had a rear coolant outlet that replaced the rear freeze plug ising an o-ring that seats on the outside of the block not in the freeze plug bore and the housing bolted in the same place as the rear billet freeze plug. I have one in the garage I should check it out to see if it’d work for you. I can’t remember if the one I have uses a gasket or O-ring.

Looks like this. But looks like it might be a square cut seal like the water pump.


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smokin247, I don't recall the phone conversation however I would gladly offer a refund for your purchase (shoot me a PM). Given your situation, I would suggest a plate like the one shown above that seals to the back of the block instead of the ID of the hole. That would ensure a good seal even if the ID of the hole is oversized.

Here's the Cummins diagram. Looks like it was used for some different coolant plumbing applications such as Air Compressor Plumbing, Cabin Heater Plumbing, Exhaust Manifold Plumbing, etc.

The main piece is available from Cummins. Probably run @ $65-$75.

Most motor homes had those plates.

Over a period of time, o-ring style plugs and heaters can leak due to expansion and contraction moving the o-ring back and forth and wearing it out.

Your problem could just be a pitted freeze plug bore, I've seen blocks so ugly that a OEM freeze plug wouldn't even fit snug in the bore.

The OEM water manifold is a pretty good solution since it's o-ring seals on the rear face of the block, rather than in the bore.