Country Coach Owners Forum Country Coach Motorcoach Forum

Generator coolant loss

October 29, 2015, 07:43:33 pm

Yahoo Message Number: 103582

---

On the last leg (3 hours) of our trip home to Yuma, our generator stopped on the road. Several restarts didn't solve the problem, so we resorted to the dash air on a 95 degree day across the AZ desert. Investigation showed an overheat trouble ode and low coolant level in the reservoir. I had installed a new Onan pressure cap about a week prior ant the coolant level was OK then.  Where did it go?

When I ordered the pressure cap, I also ordered the water pump belt, which had never been changed in our '01 Intrigue #11238, which we bought new. Removing the side panel allowed a view of the belt which was intact, so that wasn't the problem. When time permitted, I removed the end and top panels to access the belt and found the source of the overheat problem. The water pump decided to give up and leak!  A call to Rocky Mountain Cummins in Phoenix got the parts on order, including a new thermostat. The only real difficult part about the project is getting to the many bolts holding the covers on.

I'll put the covers on tomorrow AM when that side of the coach is in the shade, fill the radiator, and test the function.  Hope all is well.

Object lesson:  Be prepared for most anything.

Don Krahling

Quote Selected

Re: Generator coolant loss

Reply #1 – October 30, 2015, 08:18:31 pm

Yahoo Message Number: 103591

---

Pull the error code, and that will help on the debug.

One common problem in the QD7500 to 8000 series (And possibly others.),  were the Temp Sensors going out. Electrolysis from two different metals, and eventually the temp sensors just stop working. Without this signal showing heat, as I recall within a 3 minute period, the unit will shut down.

I replaced one once. And then when it went out a second time, had two installed. One in the normal place, and a second 'Y'd" wired into the loop, and have an A (Main temp sensor)/B (Secondary Temp sensor) metal C clamped to the metal pipe that the return (hot) hose attaches too.

By default, I run with "A" switched on. But, if/when I have another failure. I will first check for the obvious signs of no problems (Coolant/Oil levels good, no blocked passageways to the radiator, and also that the belt has not broken (Yours could be a simple as a broken belt...). If I feel all checks out good, then I will go to the "B" temp sensor, the brain will see a heat signal, and allow the generator to run. This will keep me from being stranded without a generator in a very hot area, as it did along 395 with a recorded temp of 112 degrees!! (And yeah, it was the second time the sensor went out in a three year period.)

Pull your error code, it should be stored, and post what you get. As this group should be able to help you:)!

Best,

Smitty

Quote Selected

Re: Generator coolant loss

Reply #2 – October 30, 2015, 09:38:01 pm

Yahoo Message Number: 103599

---

Thanks Smitty, but the end of my message described the problem and the fix. Good idea about the two sensors.

The only challenging part on our coach is the close confines in which to remove the panels. Once removed, the rest is a pretty straight forward and easy exchange of parts.

Don Krahling

Quote Selected

Re: Generator coolant loss

Reply #3 – October 31, 2015, 12:16:12 am

Yahoo Message Number: 103600

---

Hey Don - Thanks for pointing out the fix! I was reading this on my phone, and admit I missed both the end fix, and your signature. (And, at the same time, I was supposed to be assisting my wife find a restaurant:)! I failed at both tasks, as we passed that too:)!).

Glad you got it is fixed.

And yeah, after two failures, of which one really was uncomfortable in the heat of 395 - I went the extra mile on the A/B double heat sensor. And, I also would have noted that according to Cummins, both of these sensors are 'new and improved' - so may not have needed the second one. But for the low cost of the sensor, and then adding my time to wire a 4 dollar switch into the mix - why not:)!

Best,

Smitty

04 Allure 31017

Quote Selected