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Slight overheating problem

Yahoo Message Number: 78809
I suspect my fan controller is bad, however I would like some input from the group on how to diagnose a bad controller. My trip from Mesa to the Grand Canyon had several steep grades, however on many other steep grades (Siskouys, Rockies, Cascades) we never went much above 190; this trip we approached 210 and at one point had to stop when got to 220. Checked coolant and allowed to cool off before proceeding, but continued above 190 on several legs. It was 90+ degrees outside, but it has never heated up that much in the past. My question is how to check for a bad controller or should I be looking at something else? Roger Harper
2006 Intrigue
#11990

Re: Slight overheating problem

Reply #1 –
Yahoo Message Number: 78810
Questions: Are you loosing coolant? Have you replaced your radiator cap lately? Are your radiator fins clean. Does your fan come up to full speed when you first start your engine for 10 to 2o seconds? Does the temp gradually climb and then fall 10 or 15 degrees all of sudden while driving on flat land no matter if its 60 degrees or cooler outside? Some of these are signs of a bad fan regulator, but some could be a bad thermostat! Or a bad radiator. I know $$$$.$$
TWI 2004 Intrigue 11731

Re: Slight overheating problem

Reply #2 –
Yahoo Message Number: 78811
Could also be the sensors which you can check with a VOM meter. But I had no such luck.
TWI 2004 Intrigue 11731

Re: Slight overheating problem

Reply #3 –
Yahoo Message Number: 78816
I'm losing a bit of coolant, but I've been aware of that for the last year and I know I have the radiator replacement in the future, but this is a new problem. I have not replaced the radiator cap, but will do so today. Temp is fine on flat land and I get o sudden drops in temp while driving; just the overheating problem on the steep grades, which is new.

Roger Harper
2006 Intrigue
#11990

Cummins 400 ISL

Re: Slight overheating problem

Reply #4 –
Yahoo Message Number: 78818
Quote
Quote from: sguy48
Roger,

I'm going to go out on a limb here and suggest that everything is working fine. First, if your fan was not running at all you would hit 230 and engine shut down when running on the flats. Second, if your temp just crept up to 220 for a brief moment I would not get excited. Tom's advice was spot on but most fan failures entail low temp, not high. If on a day that is not in the 90 degree range you run up to 210-218 on a long, hard climb then I would think the top end of your fan speed is working fine. The low end is another matter. You did not say what temps you were seeing on the flats. That is where you would see a fan that is running high speed when it does not need to. I'm sure others will chime in if they think my analysis is off base. A point I'm not sure on--Tom mentioned two sensors that are subject to failure but your engine may not have these sensors. In later model coaches I think they were replaced with ECM control. This may or may not be the case on your engine.
Lyle Wetherholt
04 Intrigue 11740
04 Intrigue 11740
> I suspect my fan controller is bad, however I would like some input from the group on how to diagnose a bad controller. My trip from Mesa to the Grand Canyon had several steep grades, however on many other steep grades (Siskouys, Rockies, Cascades) we never went much above 190; this trip we approached 210 and at one point had to stop when got to 220. Checked coolant and allowed to cool off before proceeding, but continued above 190 on several legs. It was 90+ degrees outside, but it has never heated up that much in the past. My question is how to check for a bad controller or should I be looking at something else? > Roger Harper
2006 Intrigue
#11990

Re: Slight overheating problem

Reply #5 –
Yahoo Message Number: 78819
Roger:

I had the same problem and found my large air filter to be clogged. Changed it and all is fine.

Larry Reimers

06 Intrigue #11991

Re: Slight overheating problem

Reply #6 –
Yahoo Message Number: 78825
Roger

The fan controller on a Cummings and CAT is wired and controlled differently.
On a CAT when the Controller goes bad the fan does not go to high so when on level and not too hot you may get by but not when working the engine. When the controller is going bad it may work intermittently which can also drive you crazy. If the engine is hot but the fan is not on high the test is to unplug the controller which will put it into default mode which is high rpms. You can run it that way but when not working the engine temps will be below optimum and you will use more fuel.

Dan 2006 Allure 31348

Re: Slight overheating problem

Reply #7 –
Yahoo Message Number: 78828
? Dan, not to be picky but the controller on my 2004 Allure (Cummins ISL) has two plugs. One is two wire 12 volts dc supply to the controller and the other is the six wire interface to the three sensors. So in some coaches it is not enough to say unplug the controller.
Also on many coaches there is a 7.5 a fuse usually located in the chassis fuse panel in the bay under the driver's toll window. It is far easier to simply pull the fuse then crawling under the coach to access the plug in question.
My controller is so erratic in nature that I wired a switch into the dash that is in series with the fuse so I can control the high speed myself from the drivers seat. Sometimes it will go for days on end with no problem while other days it constantly starts to overheat. BTW being able to run the fan on high while in stop and go traffic help somewhat with the transmission overheating. In warmer weather I still have to drop it into neutral while the coach is standing still.

Don Seager

2004 Allure 31046

Re: Slight overheating problem

Reply #8 –
Yahoo Message Number: 78830
Thanks for the info, I'm thinking of doing the same thing on my Intrigue. I am on my third fan controller, and if I don't pull the plug with high ambient temps, the coach will dump about a half a gallon of coolant from the level recommended by the eye glass, but the temp doesn't go above 210. And I am running a 13 lb pressure cap. Will change the air filter when I see Chris in Tucson next week as part of my annual service.
TWI 2004 Intrigue 11731

Re: Slight overheating problem

Reply #9 –
Yahoo Message Number: 78831
Gees! Multiple fan controller changes, up to five on one coach! At $500 X 5 = $2500. These costly controllers are not very reliable and it may be more cost effective to eat the cost of lower mileage?

Larry, 03 Allure, 30856

Re: Slight overheating problem

Reply #10 –
Yahoo Message Number: 78836
Thanks Lyle; I decided to take the easy way for starters due to the suggestions proposed. Yesterday I flushed the system completely, replaced with new coolant and a new radiator cap and will give it a test tomorrow when we leave. I'll keep the forum up to date with the results.

Roger Harper
2006 Intrigue
#11990