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I am having a little problem with my coolant. After the truck sits for a couple of hours, it tends to want to over heat right off the bat. I let off the go pedal and the temperature falls back to normal and stays there the duration of the trip. This is happening more frequently and is really concerning me. This morning it went to hot and started blowing coolant. Of course again when I let off the go pedal it acts as if nothing is wrong. I changed the thermostat the other day figuring it would help but no luck. Today I changed the radiator cap but I don't think it will yeild promising results. Just went over 172,000 miles last week so I am starting to think the water pump is trying to hint something to me. Any kind of hints will help and I will appreciate any kind of advice given. Thanks.
Hi. I would have guessed thermostat too. At the very worst you could be getting combustion gasses in the cooling system. I was really stumped a while ago when I ran across a first in 45 years of working on stuff. The blade tips has eroded off of the water pump impeller so it was just a flat disc rotating in the housing. The symptom was different from yours though. When he would come to a stop the temp would go up unless he gave the rpms a boost to around 1500 or so then it would cool back down some. It gradually got worse over a couple months until it just wouldn't not blow coolant out of the cap. We tried all the usual stuff first. Thermostat, cap check for carbon dioxide coming out of the coolant when changed to water. Nothing worked. As a last gasp I pulled the water pump and found the problem.
Good luck.
drain the rad and seeif if there is crud built up on the tubes
check for amount of coolant flow when the thermostat opens
coolant should move fast and no back up at the cap
one other thing to check is to make sure your timing is advancing properly
I take it this is the truck in you sig. ???
I'm not sure but on a 97 shouldn't the check engine light come on if the temp keeps getting too high?
What does the Diablo Delta Chip do? If it affects timing maybe it's retarding the timing too much at your stated problem time. I would think if it retards the timing enough to get the engine that hot you would also feel a loss of power. A sluggish feel to the throttle.