My company just acquired a used 924g (will try and post a/n) and after some routine maintenance I noticed that there was barely and cab heat. Blower motor and speeds all work fine and I believe the water valve is working. I’ve replaced both cab filters, topped off the coolant and replaced the thermostat which was stuck open. Still runs very cool and I can understand why the cab heat is barely lukewarm. After running it for over 2000 rpm for a half hour I do get the temp needle to move up a bit but physically touching the heater core lines they are warm but not very hot. I’ve even tried opening the rear door where the fan is located to prevent it from cooling the rads. Still runs cool. Is this typical for this machine?
Could have something to do with winter temps. My backhoe barely gets warm at the radiator hoses after running for a half an hour, at the temperature we have now. How hot do the hydraulics get when using?
I would say it is not typical. Please supply the S/N when you have it, it helps to locate accurate information. Do you have an infra-red heat gun that you could use to shoot temperature of the coolant hoses in/out of the radiator.? What was the setting of the replacement temperature regulator that you installed.? OEM or "will fit".? At some point sooner rather than later accessing the diagnostics for the electronic control system is going to be required. IIRC your machine has a hydraulically-driven fan with speed controlled by the engine coolant temperature. If anything fails the fan goes to max speed and this could be related to your problem. From a cold start try unplugging the fan motor control solenoid connector, it's located right on the motor itself. With the engine cold the fan speed should increase significantly when you unplug- does it.?
Thanks for the replies: Nige: I will get a temp reading tomorrow in the coolant hoses after I “warm” it up. The thermostat was a direct oem Cat part. I will try what you suggested about Unplugging the harness at the fan Still attempting to decipher the s/n off the plates as they are badly corroded. Might need to call the dealer as they have it on file. Thank you for your reply Nige. Harleyhappy: The hydraulic hoses are warm but not hot. Haven’t really worked it that hard as of yet so might be a moot point I’m making. Even though we’ve had a cold spell here in Michigan, I have 3 other loaders and backhoe that warm up just fine so for an engine this size I gotta believe she will get toasty. ‘Thank you for the reply Harleyhappy.
The S/N should be stamped on the machine frame right next to the plate, usually below it. Might need a bit of wire-brushing to get it to show up. Failing that get the engine S/N. It's easy to trace the machine S/N from that. I would suggest to do it from cold. That way you get a chance to shoot a bunch of readings and to observe the temperature gradient between the inlet & outlet of the radiator as the engine warms up.