CAT 24M Overheating Problems

[DBDLS]

Working for a company that has a fleet (15+) of Cat 24M motorgraders operating in the oilsands of Alberta. Some of the machines are approaching 40,000 hours and others are in the mid 20’s. Last winter, probably because of the extra cold winter temperatures, the radiators started plugging up with tar. I would say some eventually had next to no airflow. Hard to believe but we were having overheating problems in sub zero weather. It took the shop a while to develop a protocol to properly clean out the rads but they seem to have got that figured out. They have also changed the radiators to a Mesabi product and removed the belly pans and are installing heat blankets over the mufflers, turbo and exhaust manifolds to help out. It seems now, no matter what they do they cannot get these mechines to run at cooler temperatures. Usually it is the transmission and torque that overheat first, soon followed by the engine itself. Some machines are so bad they will start overheating just travelling around. These things are running so hot they are burning the paint right off the engine compartment doors. Does anyone have any ideas?

 

[John C.]

There are torque converters in a Cat grader??? I've never heard of that.

If that is the case then leakage through the converter elements could be causing your problem. Who is rebuilding those components and are they using new parts? Leakage between the stator, impeller and turbine will make things get hot quick.

 

[Nige]

The 24 has always had a torque converter John. I never had much to do with them so never really bothered to investigate why this was so. One thing I do remember from when the 24H came out was the theory that it had so much torque and so much traction there had to be some way of de-coupling the drive if the machine ever stalled out with an overful moldboard. From what little I've seen the 24 does not spin the rear wheels as a "safety valve" like most graders.

The powertrain cooler is a conventional oil-to-water cooler so air flow makes no difference. I tend to agree with you that maybe the problem could be internal to the torque converter, especially when you consider it has a frewheel stator like an OHT. I've seen plenty of them play up before.

Like the 16M the 24M also has a hydraulically-driven fan. I would suggest to check fan speed as one of the diagnostic steps.

 

[R.D.G013]

Learn something everyday, 24 has a torque converter never knew that.

 

[Birken Vogt]

I wonder if the radiators are really doing their job. At some point I would measure temperature drop across the radiator while operating with thermocouples. My theory here is the radiator is not dropping temperature enough, and the oil-to-water cooler in the cooled lower water is running too hot to cool the oil, and the whole thing just heats up eventually.

 

[Mark250]

They have also changed the radiators to a Mesabi product and removed the belly pans and are installing heat blankets over the mufflers, turbo and exhaust manifolds to help out.


Hi, are you saying that the machines have run ok for aprox 40000 hrs and since you changed out the radiators to non OEM and other mods they are over heating?
Mark