Overheating

It sounds like you have a blown head gasket but to be sure lets run this test.

https://www.2carpros.com/articles/head-gasket-blown-test

This guide can help as well,

https://www.2carpros.com/articles/engine-overheating-or-running-hot

Please let us know what happens.

My SUV is overheating when I do not run the heater. I have flushed the system, replaced thermostat, replaced temperature sensor and gauge with aftermarket one, replaced radiator cap, and replaced water pump. Nothing has helped at all. It will run idol for about half an hour or if I drive it about a mile or so it runs normal and then it very rapidly goes to hot. I can turn the heater on and it very rapidly cools back down. I am at a complete loss so any help would be great. The truck runs great it does not smoke, tap, or knock. This was just all of the sudden and no warning. It does not leak any fluids at all and I am just not sure what to do next so like I said. Thanks in advance for any help you can throw my way.

Hi there,

I feel that you may have a partly blocked radiator, with a number of blocked core tubes you can still have some circulation, so you can flush but not all the cores are running free, with this restricted circulation you may be getting your over heating problem, have the radiator professionally cleaned by a radiator repairer, this I feel should fix your problem.

mark (mhpautos)

Thanks. I will give that a shot and let you know.