Hello, My Son has a 96 Avenger and it was low on anti-freeze. It does not run hot at idle (no matter how long and the fan cycles on and off). If you drive it at all, the temp will continue to climb. Is there anyway to identify if it is a clogged radiator, the water pump or a head gasket? There is no anti-freeze in the oil, I do not smell any anti-freeze at the exhaust pipe. The water pump was replaced with the timing belt at 70K and the car now has 135K. This is very frustrating... Thanks

It could be a number of things. You need to first have it pressure tested to rule out any minor leaks. If it's holding adequate pressure, then it could a bad thermostat or like you said, a clogged radiator or bad water pump. It could also be an external head gasket leak, which would be why you're not seeing any antifreeze in the oil.