I was out today waiting in line for some food and my temp gauge started to go to the halfway point. When I would give it gas it would start to go up even more, so I would have to turn off the car and restart it. When driving the temp is fine. When I got home I let the car run until it started to heat up again. I gave it some gas and the temp started to go between the middle and the red. Still giving it gas, the needle started to go back to the middle again and stayed there. Both radiator fans are running during this. The water pump is about 3 years old, there are no leaks anywhere that I can see and i am not losing any coolant. The radiator has never been changed. I guess I could go have it pressure tested. The thermostat isnt sticking, I squeezed the upper and lower radiator hoses. Any ideas??
so how often is it doing this? every time within half hour of heating up?
how do you know the thermostat isn’t stuck?
it only seems to do this when it is really hot outside and i am sitting in traffic for a long time. As for the thermostat, I always thought that if both upper and lower radiator hoses had pressure it is working properly. I am going to pull off the timing belt cover and see if the water pump is leaking.
there’s always going to be pressure on either side of the t-stat whether it’s working or not.
if you’re not losing coolant, then it’s not leaking.
if your fans are coming on, then the system is being restricted. either by the t-stat, the cap, or blockage.
does the cap allow coolant to flow into the tank when it starts overheating? because it should.
you can pull the t-stat and try testing it in some very hot water. while you’ve got the coolant drained, have a look at the inside of the rad through the cap and upper hose inlet. if it looks excessively scaley, you may want to take it to a rad shop and have it hot tanked and tested. if it doesn’t, run some water through it with a garden hose. make sure there’s no blockage there.
if your coolant is good, recover it. when you refill the system, be sure to follow the procedure to purge the air.
I will try that. I just drove about 60 miles round trip (most of it freeway miles), but I ran into an accident on the freeway and was stuck in traffic. I had no problems overheating. Its about 60 degrees outside, so that helps out a little bit too. I will try what you suggested and go from there. Thanks