Cat C9 overheating. HELP!

[Steve Huber Co-Admin]

Joe,
http://www.rvservicereviews.com has a number of shops in Loveland/Ft Collins but none seem to do work or are recommended for work on Class A diesels. Might want to call a few of them and see who they recommend in the area. As I noted in an earlier post, Cummins Coach Care down in Henderson got a good recommendation by a member.
Steve

[Joe DeWeese]

Is there any documentation available on this cooling system?  Who is the manufacturer?  Is there a schematic diagram showing the components and how they are connected, theory of operation?  Also, the location of the key components in my 2006 Monterey?  Any troubleshooting guides to figure out whether the fault is with the fan, the sensor, etc. 
Thanks for you help and putting up with my questions.  I’m trying to avoid taking this to an RV service shop and having them “learn” on my dime by throwing parts at the problem.

Joe DeWeese

[Dave Atherton]

Joe, information on your cooling system as we talked few days ago and you had Roy Mueller
helping you along so I back out of this. Yes I understand your problem and sounds like Roy gave you good advice on keeping Engine rpms higher. I have a few thoughts your hydraulic system that
operates cooling fan. I would suggest first before you tear down remove many parts fishing let’s check out
If the hydraulic pump is turning fast enough. You should be able to hear and see how fast the fan is
running. Check your hydraulic tank is the correct fluid present. Is your hydraulic pump hot,if there is any question as how the hydraulic fan motor can be checked. Let’s check the hydraulic motor if
There is a problem. Looking at your fan motor any will see three hydraulic hoses connected to the motor. One line is pressure that is located on one side of motor, than the fan motor return hydraulic
Oil flow back to hydraulic tank and last line is located in the middle or end of fan motor call ( case drain ). How you can check the fan motor is disconnect the middle hose called case drain and start
engine at this point there should be very little oil coming out of the fan motor. With engine running.
If you have lot of oil coming from case drain port on fan motor ( the fan motor has failed.) staying away from the cooling system because if you change out the temperature regulator every 2 years
It is unlikely having regulator problems. Forget to mention when was the hydraulic oil filter for the
Cooling fan and steering replaced. I can pull up specs for any changes but other than temperature
regulator not going to find anything. You indicated you already checked out the water pump.
Dave Atherton Retired Cat Mechanic

[Larry Shelton]

Joe, I also had the exact problem  with my 2006 Monterey C9 Cat. After lots of research and telephone calls I found that Beaver installed a Casappa hyd fan motor on some units. Spartan  also uses the Casappa fan motor in some applications so parts are available. I replaced the hyd. control element on my hyd motor and solved my problem. If you want to review some other rv'ers fixes on problem you can go to IRV2 newmar class A , and search Hydraulic fan problems by Darrel back in May 2011.