[Tantram]

I have a Kohler 8k generator with about 1,000 hours on it.

While running this weekend I jumped down to the engine room to check on something unrelated and noticed my coolant overflow tank was so overfilled that it was leaking all over the engine room.

It wasn’t overheating, but I did the usual and checked the strainer. There was some kelp and I thought that must be the issue. Cleaned it up and fired it back up. 

Again, it started to overflow. Since it wasn’t overheating I let it run for a bit and kept dumping the overflow tank. Knowing the generator only holds about 3 quarts of coolant, I looked at the coolant color and it was getting more and more watery, and less the color of coolant … leading me to believe the coolant loop is somehow taking in raw water. 

Any ideas what this could be? A heat exchanger crack? Blown head gasket?

Any ideas to try to rule out or confirm anything?

Thanks all.

[ReelMagic]

I had a similar problem years back with a 454 Crusader FI engine. It turned out to be a cross port leak in the heat exchanger..... When the engine is running salt water leaked into the fresh water side of the heat exchanger which caused an overflow to the coolant recovery tank...After running for a while the amount of water/coolant caused the overflow tank to overflow into the bilge.. M2C