Engine overheating on Cummins ISC 350 Fan not turning

I think if you pull the fuse for the fan, the fan will default to high speed and then you could still continue your vacation. Then fix it when you get back.

Yes, that was the first clue. Bolted it back together, thought maybe it acted as a heatsink. Fan started to work. Started driving and it overheated again and the fan had stopped. Had a mobile mechanic looking at it for almost 6 hrs and he first said it was bad and then pulled it out and tested it and said it was good. He thought maybe it was the pump. He got the fan going. Drove it around again and started overheating. He gave up and said to take it to freightliner.
I still thought it was the fan control module and after talking to Freightliner in Gaffney SC, the Tech also confirmed that he thought that is what it was...
Just got to get a part now and give it a try... Gave up on the vacation until we know it is fixed for sure..

Those expensive fan controllers are very unreliable...

Awesome. Thanks so much....

stevekaufman wrote:
we have narrowed it down to the Hydraulic fan control module (this is the part that I had found that the bolts had came out and was in two pieces, with the front piece dangling from the wires. I bolted back together but still didn't work).
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Gee, the first clue. :S :h

This place has them. Price should be somewhere in the ballpark of 600.

http://www.bfpna.com/default.asp

Thank you all for the replies and great info.
After testing, checking, and then speaking with Freightliner in Gaffney, SC, I think we have narrowed it down to the Hydraulic fan control module (this is the part that I had found that the bolts had came out and was in two pieces, with the front piece dangling from the wires. I bolted back together but still didn't work).
My next question is, does anyone know where I can purchase the part besides Freightliner? Freightliner of Utah quoted me $800 and said it would need to be shipped from Reno.. The part is a Sauer Danfoss #1090385 hydraulic fan control module.

Thanks again for all the replies and great tips in helping diagnosis the problem.

Here is portion of an email from a friend with the same problem.


. Steve, the mechanic, asked many questions about the symptoms and history. He would start by checking the fan performance. It was unlikely, but possible, that the water pump shaft had failed. If necessary, we would be able to stay in our coach overnight with 15-amp power available.



Steve soon determined that the fan was not operating properly. The fan control module was not working as it should. This part has been replaced 4 times since we bought the coach in 2001. I had always been told that it was not a serviceable part. Steve took off a cap and tried to activate the valve manually. It was stuck! He disassembled the other end and eventually was able to remove the piston that moved inside the cylinder. He cleaned and polished the piston, reassembled the system and we retested. The fan was now operating at both high and low speeds. Steve collected a sample of the hydraulic oil for analysis. Steve’s opinion is that a small spec of rust or dust collected in the valve. He recommended that the engine not be allowed to sit for long periods without being exercised….



I drove the coach back to the campground and a few miles beyond with the A/C on to load it up a bit. Ran cool as a cucumber! The Appalachians will be our next real test in another month or so.

So, based on what the Salt Lake techy said if the power steering still works fine, no increase in steering effort, you do not have a bad pump. The fan motor (actually a hydraulic motor) is not running but still turns, you might check the priority valve, I think that's what they call it. As I understand, it regulates the flow to the two devices since two systems run on the same hydraulics. If it is like mine, follow the pressure line from the hydraulic pump to a junction block with 3 or 4 lines into it, about 3 X 3 X 1 inch steel. Check with Salt Lake to determine the procedure to clean this valve, but in my case the regulator plunger was removed, cleaned with a solvent, then re-torqued back in place.

This is the procedure that Spartan ran me through to repair a overheating/lack of steering problem that I had a few years ago. As it turned out the pump was going bad and not capable of running both fan and steering at the same time, but they had me check the priority valve.

Good luck.

Thanks so much for the quick response.
I tried calling Freightliner in Gaffney but missed their closing time.
When I spoke to the mechanic from Freightliner in Salt Lake this morning, he had asked if the power steering was okay and said they were ran on the same. He was the one that told us to disconnect it and that the fan would run...
I will check the fan motor and filter at your suggestion and let you know. The fluid levels are good too.

I really appreciate the help.

Thanks,

Steve