Heat Exchanger plumbing

[charger 69]

I was looking at the plumbing for the heat exchanger on the right side of the block. Correct me if I am wrong but it looks like the line first comes out of the top of the head where the temperature sender unit is and goes to the heater core returns over the exmaust manifold, turns down and routs along the side of the motor to the rear of the exchanger.The other line comes out the front of the exchanger and returns to a point somewhere on the block. Now if I could run this return line through a cooler of some type it should lower the engine temperature noticeably I would think. I already have a fan assisted transmission cooler for the hot line on the transmission but its the motor temperature whick I am concerned about. The truck doesn't think about getting hot till I hook onto the 12K GN. and then on the hills it hits 230* in nothing flat. Thanks for reading and any ideas.

[KTA]

Check for a bad fan clutch, a new one made a BIG diffrence in engine temps on my trailer puller.

[charger 69]

To change a fan clutch you need acouple of special wrenches don't you?? Also is it worth getting it from Cummins or is an aftermarket OK? Thanks