Citation Sprinter genset overheating problem

[Free Ranger]

Recently purchased a new 2014 Citation Sprinter and immediately found that we are unable to run the AC from the genset if it is more than 88F outside. The genset just shuts down. Contacted Thor immediately and was only told to get the generator to an Onan service center, which we did. Onan tested the unit and found that the intake temps for the genset were very high and exceeded their operational limits, causing the genset to shutdown. The dealership is working on the problem but Thor seems to be telling them that they, Thor, are not aware of any operational problems with their coaches. I doubt that this is the case. Has anyone else had this issue?

[brianh442]

Howdy Ranger,

I feel your pain, I had a 2013 ACE 29.2 and had the same problem. I even had the problem when driving down the highway at 60 mph, if the temp was above 85-ish the Gen would shut down. After research and talking with a mechanic it appears that the design of the generator mounting limits and in some cases restricts air flow for the gen.

They (Thor) had come up with a work around for the ACE, if I remember right, some type of heat shield was added to cut down on the heat from the engine compartment and there may even have been a device for airflow as well. You could probably do a google search for Thor Generator overheat problems and you'll find some stuff!

In my experience I found that if I was driving and it was really hot, I would run the Gen and the coach AC's until it shutdown, then I wouldn't run it again. If I was stopped and conditions permitted, I would open the gen compartment door as well as remove the green cover to allow for more air flow. Also try opening adjacent compartment doors to allow for more airflow.

I figure it's a good thing when the gen will auto shut down for overheat conditions, after all the unit is trying to protect itself from serious damage!! The hard parts just trying to prevent the overheat condition!!

Hope this helps!!

[Free Ranger]

Thanks Brian, I'm just mining for any and all experience out there with other Thor owners. Seems to be a lot of folks, especially with the ACE, who are going thru the same thing. I cannot believe that I'm the only Citation owner to have this issue, especially since it has occurred every time we really needed to run the air. Both Thor and my dealer have suggested just keeping the door open but that seems like a poor way to do business on a relatively expensive coach. Seems like TMC has a basic design flaw. Onan has suggested a vented door as a possible fix, but Thor does not seem to be jumping on that fix. So, has your work around solved the problem in your ACE?

[brianh442]

Out of curiosity where is the Genny located on the chassis, towards the front near the engine, mid or rear? On the ACE, it was up front on the drivers side, near the engine compartment. It seemed the heat from the engine would flow aft while driving down the road and would interfere with the operation of the Genny. If you factor in the heat generated by the tires and drive train as well, it all took its toll.

I never had my Gen modified, I traded it in for a Miramar 34.2. On the Miramar, the Gen is located on the drivers side rear, just aft of the axel. Runs fine while driving down the road in 90+ F temps. So far, no issues, while parked!

It seems the basic issue is air flow or venting? There must be some thought into directing or flowing ambient air, so it will carry the heat from the engine away from the Gen compartment! I know this is easier said than done!

[Free Ranger]

Brian,

Genset is in the passenger side rear compartment just behind the wheels. A tight compartment with only an inch of clearance between the generator and the door when the door is closed. The engine exhaust also runs right behind the genset.