If your Onan leaks coolant after it warms up check this out.

[nodine]

My Onan 8000 Quite Diesel generator started leaking coolant after the cooling system warmed up. At first it was minor and I thought it was just coming out of the overflow. Not so and it got worse. I replaced the radiator cap as required by the manual every two years but that did not solve the problem. At this point I knew it would be necessary to explore inside the generator and took the top off. I could see that the leak was coming from the bottom of the radiator near the lower hose but accessing that location was very difficult. I attempted to tighten the hose clamp but it seemed tight. Through not an easy task, I removed the radiator and the photo below shows what I found. Onan apparently used a hose clamp that would not close small enough to sufficiently seal the hose. I found two of these hose clamps, both on that hose. The other hose clamps would close further and I tightened them. There was one that was not accessible without a drastic dissemble of the generator. I have my fingers crossed on that one.

Bob