[Danwellman25]

Okay so I have a 2000 STS. I replaced the thermostat ,water pump, coolant temp sensor, and reservoir. It used to over heat right away but after flushing the coolant it doesn't overheat while driving. As long as under 4k it's cool, but when idling and accelerating faster than 4k it overheats. I'm at a loss of what's causing it. I drove it 25 miles nice and easy no problems. Any help appreciated!

 

[Ranger]

Have you checked the purge line to be sure it is clear and flows coolant?
WP belt tensioner?
Have you checked the condenser to see if it is clear and not clogged with dead bugs?

 

[Submariner409]

Yup ^ ^ ^

Check the purge line for flow at idle - that's what keeps air locks out of the system - heater circuit is most affected. Rod out the hollow bolt/nipple at the water crossover.

 

[Danwellman25]

Yes i checked that line when I did the water pump. It did have something in it but its clear now. Radiator on the outside is clean. Not sure about the inside. The heater core was plugged so I bypassed the heater core. I have some coolant flush and cleaner in it right now. The only thing I can think of is a partially clogged radiator or coolant jacket.

 

[Ranger]

The heater core was plugged so I bypassed the heater core. I have some coolant flush and cleaner in it right now. The only thing I can think of is a partially clogged radiator or coolant jacket.

If the heater core was plugged, chances are, so is the radiator.
How long have you had this car?
How long has this problem existed?