Onan Generator 7500 Quiet Diesel

DANO2014 wrote:
OK, brought coach to have my generator checked out for previous stated problems. Technician found the Fault Code No 36 and checked out unit. Could not find any problems so I instructed him to change Oil & Filter, change out fuel filter and air filter plus anything else that he thought necessary to eliminate issues.
Tech ran it for 2 1/2 hours with a full load, no problems and I ran it for another 2 hours, no problems.
Left for a day trip about 220 mile r/t. Generator worked great on the way down. Parked coach left generator running with full load and was gone maybe 3 hours. Came back to coach, generator had stopped running..checked oil level-OK, Fault Code again was 36. Restarted unit but was a little sluggish and I had to hold down on my start button until it started. I normally don't have to do that once the glow plugs heat up it cranks with ease. It stopped again on the return trip after parking for about an hour to eat dinner. Came back out and generator had stopped again....cranked again and ease the load by cutting rear A/C off running just the front...ran OK all the way back home which was about 2 1/2 hours, no issues..
I am bringing it back to the repair facility in the morning in hoping they can find the problem....I am beginning to think it could be in the coolant and/or thermostat? Confused by not giving up !
Any suggestions would be greatly appreciated....sorry for the long message.

Well Sir,
As I stated earlier in my previous post, if you were having an "over heat" condition, it would present a code 33. Now, this does not mean you're not having one, it's just that, it's typically going to produce that specific code if, there's any of the conditions exist, that would cause a high heat condition.

While these 7.5 QD units are great little generators, they can throw fits now and then that cause some head scratching. I have corresponded to a few on here and IRV2 that have had that "over heat" condition and, for about 99.99% of them, the cause was the infamous temp sensor, located in the lower thermostat housing.

The temp sensor is about the same shape as a spark plug. And, the condition is resides in, is real close proximity. In other words, there's very limited flow of coolant around it. So, being in that kind of environment, it eventually builds up a hard calcium type corrosion all around that sensor and, therefore, sort of "grounds out" which, causes false signals to that little diesel ECM.

It's actually presenting an over heat condition, when in fact, the little diesel is running just fine. But, the ECM can only respond and, act on, what it's told are operating conditions.

Some, like me, had one serious pain in the a$$ time of getting that sensor out due to the corrosion on the threads and sensor tip. But, others, were not so bad off. Theirs came right out.

There was one gent, I think he/they go by the user name of "Joe and Angela" who actually by-passed the sensor, faking out the engine ECM with a new sensor, taped to the radiator hose, emanating from the thermostat. IT WORKED! That little engine kept right on running in the hottest conditions.

So, anyway, you'll have to do a bit more investigating to see if that's your problem and, it's just not throwing the correct code. Good luck.
Scott