i have a 2000 trail head edition with a 3.0. had the truck about 18 months no problem until recently. it started overheating at low rpm's when the engine is laboring. idle sitting still can sit for a few mintes before starting to creep up. highway speed no problem. under 2000 rpms going down the road and that is where the problem begins. it starts to overheat. speed up and it goes back down. flush it out twice, it was rust colored, did not help. today changed the themostate and rad. cap, no change. tomorrow probably will replace the radiator. the lines running to the intake have been bypassed. i have noticed no white smoke. no water in oil. heater does not warm up. help please

My buddy had the same problem in his 94 b2300, the cooling system is probably blocked up partially and just a standard flush is not going to work, he ended up changing the tstat, hoses, radiator w/ one from a 4.0, and had it flushed at his shop before it would cool properly. What happened was the previous owner had neglected regular maintenance on the truck and caused the coolant to begin to rust away the cooling jackets in the block, causing all the blockages in the system. So if you can afford it go ahead and get the 4.0 radiator, should not be that much more expensive... and i see that you said when you speed up it cools down, check the water pump pulley and make sure the bearings are still good, also check the fan and make sure the clutch is not locked up on the fan. And when you say the lines running to the intake were bypassed do you mean the ones from the firewall to the intake? cause if so then that would be why the heater is not getting warm... also and i know you probably already checked but make sure the coolant level in the radiator is high enough. w/ the blockages it may have blocked the little hose that goes to the over flow tank and the overflow tank my have the right amount of coolant in it and the radiator could be a little low... but these are just suggestions based on experiences i have had working on cars and trucks, and what happened on one in particular... may not be the reason yours is overheating...

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not the radiator,,,just replaced it...