Cat 300 running hot on gradea

Probably not what your looking for but on my older CAT (3176B), I always tend to run in 5th gear in order to keep my hydraulic Fan running at a higher speed. In my 15 year's of ownership and traveling in the worst of heat(110+ degree's), it has never failed me. I only release it to 6th gear on the level-est of highways.

Yes, keep rpm's up high before it has a chance to get hot.
Run mine at 2500 minimum when starting up a significant grade.

That's one of the faults of a rear radiator, and one of the reasons the larger DPs went to a side radiator.

Best you can do is keep it clean, and run as others here have suggested.

Well, I do have a side radiator and still keep my eye on the temp. :-)

Bob,

Have you replaced the thermostat(s)? After 12 years, may not be opening all the way.

BTW, Caterpillar calls them "regulators".

Pretty easy to replace from above after draining a gallon or two of coolant.

fishingbob61 wrote:
In 90+ weather when pulling a long grade my 05 Bounder 34m with a 300hp Cat will run in the hot on the guage and the yellow light comes on, I will down shift and let up on pedal. When top of pull it cools down. I had it at Freightliner and they cleaned out the rad and cac and adjusted the water pump belt, helped some. Any thoughts?

seeing as the rad etc is clean the only thing I can think of is the fan clutch is weak and slipping ?
I know my 425 side cooling ISL will run 200+ on a hard pull and as soon as I lift and start coasting/cruising it backs right back down to 180 area;;

Acampingwewillgo wrote:
Well, I do have a side radiator and still keep my eye on the temp. :-)

I do too. but it is never a problem.

I do wash the radiator Zep super soap, and a hose.

hostage wrote:


seeing as the rad etc is clean the only thing I can think of is the fan clutch is weak and slipping ?

Two points:

Most rear radiator coaches have direct drive fans, not clutched fans. Yes, there are a few, particularly newer ones that are clutched.

While cleaning the radiator is important, it is critical to understand the the vast majority of the blockage will be on the FRONT (toward front of coach) of the CAC (Charge Air Cooler) which can only be accessed from the front (through the bedroom or closet).

wolfe10 wrote:

hostage wrote:


seeing as the rad etc is clean the only thing I can think of is the fan clutch is weak and slipping ?

Two points:

Most rear radiator coaches have direct drive fans, not clutched fans. Yes, there are a few, particularly newer ones that are clutched.

While cleaning the radiator is important, it is critical to understand the the vast majority of the blockage will be on the FRONT (toward front of coach) of the CAC (Charge Air Cooler) which can only be accessed from the front (through the bedroom or closet).

I have more practise on side cooling but the few rear I have seen are clutch controlled hence my comment;also the OP clearly said the CAC was cleaned so one has to assume it was done and done correctly

I've driven a 300 hp CAT for 15 years and if you go up hills at full, or near full, throttle it will heat up. You have to keep a close eye on the gauge, when it starts to heat up you just downshift and slow down. My fan is direct drive and the only way to cool the engine is to bring up the revs. In some cases I'm in the truck lane but I don't overheat and we get to where we're going without a tow.