G_MAN
Guest
The first thing I would do would be to verify the accuracy of the temperature gauge and it's circuit. I would install some sort of mechanical temp gauge in the cylinder head, mount it back by the engine, and as soon as the gauge in the cab reads hot, run back and check the mechanical gauge. I've seen several tractors that were supposedly "overheating", but in actuality, the temp gauge circuit, sender or gauge was at fault. That you mention that it "suddenly" rises and falls kind of leads me to believe it may be an electrical problem, as all that coolant just can't change temperatures in matter of a second or two. It sounds like you've covered the basics as far as fixing a real heating problem, except for the water pump. The gear-drive pump on the 6076 is generally pretty trouble-free, but I have heard of one or two with slipping impellers. I'd also take a good look at the intercooler, as if it is plugged up, your intake air temp goes way up and can cause an overheating situation. I've seen some very nasty and plugged intercoolers in 9000 Deeres. I'd also make sure that while washing out the radiator, you haven't folded a bunch of fins over. Generally, high-pressure water is NOT a really good way to clean out a radiator, unless you be sure to blow directly through it in a straight line. So in order of easiest to hardest, I'd first inspect the radiator and cooler, then install the temperature gauge to verify temperature, and if all that fails, check out the water pump.