Chrysler Repair: P/T Cruiser 2002 overheating, coolant temp, coolant level

Question
My P/T cruiser overheat once and water come out I check everything and replace the block thermostat for the fan, it run well for a wile but as I get in traffic it over heat again this time I press the accelerator and water temperature when down to normal I did not run it any more I was afraid to blow the engine.I will change the anti-freez next to see if this do the trick, cause I add water after it overheat and replace the block thermostat
What else can I check the fan run well the pump run well or so I see.
Thank
Roberto

Answer
Hi Roberto,
Are you routinely loosing any coolant to the ground, or do you see any unusual amount of white smoke come from the tail pipe when you first startup the engine in the morning? Either of those would be a sign of problems with the cooling system (leaks in the radiator or water pump or hoses, or a leak in the head gasket). When you refilled it did you perhaps get some air trapped in the system so that it really wasn't filled with coolant? When you start the engine and let it warm up at rest do you hear any bubbling coming from the engine or the radiator or the hoses? Is the fan coming on when the gauge is pushing toward hot? These are all relevant observations, so let me know if you have observed any of them. Which size engine is in the car?
If you have the 2.4L engine, then when you are refilling it you must start with the coolant temp sensor that is located above the thermostat housing REMOVED. The sensor has two wires: black/light blue and tan/black. You refill the system until the coolant level reaches the hole for the sensor; then you put the sensor back in and continue the refilling process. (Torque it to 5 foot-pounds, which is not very much, so you don't want to crack the housing by overtighteneing it).
For the first few drives after you refill, you may need to add more coolant as air is driven out of the system.
But if you didn't have the coolant temp sensor removed when you last refilled it, there may be air trapped at that point which causes the thermostat to open late, rather than as needed, so that would cause it to run hot.
Those are some ideas for you to consider.
Roland