Anyone have thoughts on why the temp on my Cummins will climb while under a good load? It's a '99 quad cab 4X4 with auto.
Normal unloaded temp runs 190*. If I'm towing the 5th wheel, which weighs 12,000, and I stand on it hard to merge into traffic or to go up a hill, you can actually see the temp guage needle start climbing. I'm not pulling in overdrive, but if I switch the overdrive back on while on the flats, the temp starts dropping.
It did this about 3 times last summer while double towing the 5th wheel and boat and got so high the warning bell sounded to "check guages" and the temp was right at 240*
Radiator is at proper level with 50/50 mix, and the fins don't appear to be clogged with bugs.
Any thoughts?