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Onan Generator Coolant Leak

Yahoo Message Number: 64993
My 7.5 kw Onan has developed a very small coolant leak that I can see through the bottom access door as drips of red coolant on fasteners and on the floor of the generator. Coolant level has dropped only about a cup. I ran the generator and could not see any additional leaks but none were evident. I removed the oil filter to see if I could see the source of the leak without luck. It seems to be originating on the top of the motor. I cleaned up all of the leaks and let it stand overnight and the drips were back. My next step is to drop the generator, ugh, and pull the enclosure to find the source of the leak.
Does anyone have any ideas about the source of the leak or any words of wisdom about dropping the unit. I plan on buying a motorcycle lift to get the unit down.
Bob Cole

2005 Inspire 51394

Re: Onan Generator Coolant Leak

Reply #1 –
Yahoo Message Number: 64995
Bob,

We had leak in our unit also , it drove Scott crazy trying to find it. It was in the reservoir, the nuts that are molded into the plastic container had stress cracks around them. It was VERY difficult to see. I would start there first. If that is the case you will need to call Onan for the part, but it was not difficult to replace.

Marta

07 Allure 31501

Re: Onan Generator Coolant Leak

Reply #2 –
Yahoo Message Number: 64997
Bob,

I had the same leak. As with Marta, the plastic reservoir was leaking and had to be replaced.

Dave

07 Inspire 52060

Re: Onan Generator Coolant Leak

Reply #3 –
Yahoo Message Number: 65013
Do you know if the plastic reservoir can be replaced through the front access panel or whether the generator needs to be dropped and removed to make the repair?

Bob

2005 Inspire 51394

Re: Onan Generator Coolant Leak

Reply #4 –
Yahoo Message Number: 65019
Isn't plastic great! Works great for radiator headers too.

George Harper
04 Allure
31093

Re: Onan Generator Coolant Leak

Reply #5 –
Yahoo Message Number: 65027
Bob,

We have a slightly different model than yours (10KW), but on ours Scott removed the tank reservoir through the access panel you use to change the filters and check the oil. He actually found the leak when he removed the tank to change the air filter which was behind the reservoir.

Marta

07 Allure 31501

Re: Onan Generator Coolant Leak

Reply #6 –
Yahoo Message Number: 65030
Bob,

With all the access covers on the generator, I can't imagine you would have to remove the generator to replace the tank. Mine was done by Cummins Atlantic in Richmond, VA. Don't take long to complete and as a bonus, it was covered by Cummins.

Dave

07 Inspire 52060

Re: Onan Generator Coolant Leak

Reply #7 –
Yahoo Message Number: 65034
Ken here, I agree on the Plastic Res. leaking or cracking, In our shop I pressureized the whole cooling system just a few PSI first on the cold engine with a pressure ga., if there was no loss of pressure or coolant leaking I then retested the cooling system on a hot engine. Yes I dropped many a generator in my day raising up the coach on a ramp or the pit, using a forklift or a big sissor platform. Our Cat shop had the best lifting eqpt. I first always Capped off the fuel lines, Taped Battery leads and A/C Power cables on the side. The biggie is removing the exhaust system tail piping and removing the coach grill. I always had two coworkers helping. We always worked flat rate, Just get work done in writing first. If leak is found repaird it also replaced belts and hoses at this point. Be safe leave it to the pros! Ken 99 Allure 30356