I got a call from RJ Sunday afternoon. A fellow bus nut (Ian) was in Boston and his generator was shutting down on overheat. I talked with Ian for a while and got a good idea of what the symptoms were. When I asked when I could take a look a the generator he said "I'm on my way". He was at the house by 7pm!
We spent a couple hours looking at things Sunday evening. It was pretty clear that several years had passed since the generator was in good order. I think it's a PowerTech generator with a 12.5kw head, but there is absolutely no brand info on it at all. The engine is a Kubota V2203 4 cylinder, 1800 rpm, 48hp with a rebuild tag on one of the freeze plugs.
Two weeks ago a generator dealer installed a 160F thermostat in it when they discovered it didn't even have one. They had a difficult time bleeding the air from the system. This is what the plumbing looked like before we got into it.
The Eagle is setup as an Entertainer coach and is currently on a 90 day tour with a band. The bus has an inverter but the batteries were removed before the current owner purchased it, so to keep the fridge, heat, AC, outlets, etc, running, the generator has been going basically non-stop for the last 30 days, save for breakdowns. Breakdowns mean no AC in the bus for the band members, no heat, no electricity. Not a happy band!
So this is what I found: The two week old thermostat stuck closed. Will not budge. Absolutely NO water flow from the water pump at all even with the thermostat removed. Zero. Closest water pump is in NJ at Kubota's distribution center and by this time it was 3:30pm. The coach needed to be in Boston tom'w with the band's equipment trailer so ordering a new pump and waiting for it to come in wasn't an option.
Here's how I fixed it:
I re-engineered the cooling lines so that the reservoir tank was entering the system at the highest point. I took a 3/8 line from the return side and ran it to the reservoir tank. By doing that, coolant flows into the tank and gravity pushes the coolant into the system from the highest point. In addition, air from the coolant loop would burp up through the 3/8 line into the tank. I used a Taco zone pump to replace the engine driven pump. I also had to remove the seized thermostat since we weren't able to find a replacement. The zone pump is 120vac so I was able to run the pump while I filled the reservoir with coolant. The pump then purged the system of air in a matter of minutes! The zone pump is plugged into an outlet that is energized when the generator starts.
I raised the reservoir tank 5 inches and reduced the dip in the line. The 3/8" line goes to one of the inlets that the looped hoses attach to. This helped get coolant into the system and made it easier to bleed. This was the old setup for the reservoir tank.
We also made some quick repairs to the radiator and fan box by making them more air tight.
Here's a shot of us finishing up the modifications. LOL!
No more over heating! The Taco will act as a redundant pump when the new water pump is installed, and it made bleeding the system infinitely easier! We were able to purge the system without running the engine!
Happy band, happy tour company owner, happy coach driver, lousy generator setup.
And it was a blast to meet and work with Ian who owns the coach. He's put 9k miles on it in the last 8 weeks!