Engine is overheating?

You might want to consider having a chemical test done to check for a leaking cylinder head gasket. That involves drawing air from the radiator through a glass cylinder with two chambers partially-filled with a special dark blue liquid. If combustion gases are present the liquid will turn bright yellow. Those gases can pool under the thermostat and prevent it from opening, depending on which engine you have. Thermostats only open in response to hot liquid, not hot air. But to be sure these guides will help us fix the problem

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

and

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

Please run down these guides and report back.

Has the engne actually overheated? I question if the temp sending unit is bad. Also, does it only overheat when in traffic or will it at highway speed too?

I agree with you. The radiator should be fine. You may consider having the engine block flushed, but I honestly question if that will help. Also, does the engine run good otherwise? I wonder if there is a head gasket problem.

I agree with you. Chances are the radiator isn't the problem, so a flush would most likely be a waste of money.

As far as the head gasket question, you would need to do a compression test. Then you could check to see if there is a cylender with low compression.

If this only happens with the ac on and you have done everything you described, I question if there is a problem at all other than a faulty coolant temp sensor or some short that is causing the gauge to raise. Another thing you could try (to make sure the gauge is accurate) is to rent a radiator thermometer. With the engine cold, open the radiator cap, put in the thermometer, start the engine with the AC on and see what temp the coolant in the radiator gets. It should stay around 200 degrees F.

Here is a how to for checking compression if you need it:

https://www.2carpros.com/dia/how_to_check_compression.htm

Something tells me with everything you have done, something is causing the gauge to misread.

Let me know what you find.

Joe

What all has been replaced? Could be many things causing overheating from faulty radiator to clogged heater core, bad thermostat etc.

Looks like still waterpump, heater core and radiator not yet checked. Suggest flushing system including heater core and inspecting waterpump. Also ensure radiator fan(s) are coming on properly

Hi:
Is the coolant boiling? Are you sure the gauge is correct? Have you ever had the cooling system flushed? Replaced the thermostat?

Joe

Seems like there may be weak pressure in cooling system, this could be due to a clog in the system ( dirty heater core etc.) Or even a failing water pump

I think it is the head gasket. but first lets check the wires, if this is a distributor, then check under the cap, also check the map sensor, check anywhere that the coolant may have sprayed, also check vacuum hoses going to the intake manifold.

These guides can help us fix it.

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

and

https://www.2carpros.com/articles/engine-misfires-or-runs-rough

Please run down these guides and report back.

The coolant will pull back in the radiator when the engine cools down but this will not happen if there is a small coolant leak somewhere. As far as the overheating problem, first look at the for a partially plugged radiator and then the water pump.

Hope this helps,
Bob