I have a 1996 Acura TL 2.5L with 175k miles on it. Recently I have encountered a problem that I am beginning to feel is serious. When I start the car and drive for a few miles the temperature gauge reaches normal running temperature. If I have to stop at a long traffic light or railroad crossing the gauge begins to climb towards the H. If I am able to move the gauge sometimes will return to normal, other times it will only continue to climb. I have to stop and turn the engine off for a few minutes to allow it to cool down. Secondly, I have noticed that if the temperature outside is cool or cold (40's) and I am on the freeway, the temperature gauge will drop way below normal, almost to the C. Of course when I come to a stop the gauge will return to normal once again.
I am concerned because apparently this is a problem and I cannot efford to have the engine overheat because I am aware of the damage associated with that happening. The coolant level is correct and the coolant is still green in color. I have been looking for any signs of leakage by placing cardboard underneath the vehicle and allowing it to run and to no avail have found a leak of any kind. I have read forums that stated it may be the thermostat or the the water pump but I am still very unclear. Also there is no change in the heating system when the heat is turned on or with the A/C when it is turned on. The cooling fans do run to the best of my knowledge because I hear them running when the vehicle is turned off for a few moments. Any help would be appreciated. Thank you
