Onan HDKAK QD8000 H-Spec Gremlin
Looking for an idea from the brain trust. I have the above referenced Onan in my mid-engine. We are dry-camping in Atlanta at the motor speedway. Ran the genset on the way up from NW Florida--4hrs straight on the road, not a hickup or fault. Got here and it ran fine...for about six hours. At around 1am, I noticed it had shut off. It would only run for random periods from 1min at its shortest to about an hour. The ONLY code I got on both the remote display and the flashing switch, was a Primary Fault 3, followed by a fault 33. Yes, I know that 33 is NOT supposed to be a code to avoid confusion with the service fault (3 flashes). The remote display showed a "33 - Coolant over temp" fault. Only problem was that we were about 36-F ambient, no obstructions. Serviced oil, filer and fuel filter about 29hrs back.
So...I went to Home Depot and rented a 3000kw Honda intending to just run the bus off of that. And...the genset ran for the entire afternoon. It did shut down twice, each time only giving the top-level 3. No other faults are now indicated.
Any ideas what might cause the gen set to shut off like this with no hint? It has done this off/on since I acquired. I thought it was a fault with the Auto Gen Start, but that is in manual.
Appreciate the assist.