Thursday, September 15, 2011

Overheating 99' Chrysler Concorde and changing the thermostat?

My 99' Chrysler Concord with a 2.7 liter six cylinder is overheating in traffic. The electric fan does not turn on when the temp gauge is climbing. Would a themostat cause both of these problems. Is the thermostat right on top of the block under the line to the radiator like in older cars? The last car I changed a thermostat in was a '75 AMC Jeep CJ-5 so I am a little behind on the technology. Any help or advice is welcome?
Overheating 99' Chrysler Concorde and changing the thermostat?
You have a thermal switch that senses temperature.It should have only one wire to it.When it closes on temp. rise,it sends a ground to the fan relay.If you jump out the wire on the thermal switch to ground,the fan should come on.(Make sure your ignition is on when you test this)If the fan comes on the thermal switch is bad.If the fan does not come on you need to find the relay and determine if it is bad or has a blown fuse to it.
Overheating 99' Chrysler Concorde and changing the thermostat?
Yes the stat is still on the block. However those electric fan motors also have a sensor, which could be the problem. In which case you may want to have them replaced. Use a jumper line and direct feed the power, bypassing the sensor, and run continually. Hook the line to switchable power source, like ignition. If you are going to change the stat, back-flush the cooling system first. Use a product like Zerex or Prestone raditor flush.
I don't think a thermostat would cause both problems. It would cause over heating if it was stuck closed but it would not prevent your fan from coming on. You should follow your top radiator hose to the engine block. The thermostat should be inside the hose.



The fan may not be coming on because you might have a blown fuse or possibly a solenoid or relay is not functioning correctly by letting the voltage through to turn on the fan or the fan may not be grounded. I would say that there should be a device to let electricity through to the fan when the engine reaches a certain temperature to turn on the fan but I don't know what it is. On my prizm it was caused by a relay in the fuse box.