escort 1999 overheating?

My daughter told me that when the speed of her car is above 70 mph, the temperature needle is near the 3/4 mark. She said that it used to stay near the middle. I asked her to check the coolant and the engine old levels and she said both are fine.

Anyone can tell me what might be the problem?

Thanks for all the comments.

The car got hot very quickly and shut down. I came to inspect it and found out that there was not much coolant in the radiator although the container was almost full. I put coolant into the radiator and managed to drive the car home with both a/c and heater on. The gauge showed that the the temperature was in the middle most of the time. Occasionally it was near the hot mark.

Please help me correct the problem.

My questions to the experts are:
1) How come there was not much coolant in the radiator while the coolant container was almost full?
2) How can I check if the thermostat is not working?
3) How can I find out if the water pump is OK?
4) Where could have all the fluid in the radiator go?

Thanks

Pressure test the system for leaks.

How does one do a pressure test?

when the engine is cold, start it up and go to the upper radiator hose. Wait as the engine warms and feel on this hose for heat and pressure. INitially, with the thermostat closed and engine cold you should not feel much of anything. Once the temp comes up and the thermostat opens, you should feel a rush of warm water through this hose. A few things can happen-
1. The water does not rush through the hose as expected, which suggests the thermostat is stuck or the water pump is not working. Usually, feeling at the bottom hose will tell you if water is circulating through the pump or not.

2. Water does rush through as expected, but perhaps not a strong flow. In this case suspect a blockage in the radiator.


Also, if coolant is missing, consider a possible head gasket leak and check the oil. The oil on the dipstick will usually look somewhat creamy if it has coolant in it. You can also just crack the oil pan plug and see if any water drains out of it first as the oil will be settled on top of it.

To do a pressure test you can rent a tool from the parts store and it will only take a minute to do.

It turned out to be the thermostat. The replacement job was completed in 1/2 hour, although I had some scary moment because one of the screws broke.

thanks for all the help.

You need a pressure tester, looks like a bicycle pump, to pressurize the system. Some chain auto parts stores may loan or rent the tester. The same tool is also used to test the radiator cap.

I'm glad your overheating problem was an easy fix.