Expert: Sean Halliday - 7/30/2006

Question
I have a 1993 Toyota Mark II Grande, Right side steering with 113K on it.  It overheats from time to time, normally after about 40mins of driving it.  I had the thermostat and radiator cap replaced but that didn't stop the problem.  Any idea what the problem is.  #2.  If I have a leaky head gasket how would I as a vehicle operator be able to identify this.

Answer
Does your car use coolant?Check to see if it is leaking and if so ,repair should stop the overheat ,if not then do a vacuum test if you can and that will show whats going on.Having 113000 miles it may be the gasket if the car has ever really got too hot,another way to tell is do a leak down test but a shop can only do this.No real way to say for sure as you will find eventually that the gasket will blow completly and lose a lot of coolant suddenly.The problem will get worse and overheat faster thats if no visible signs of coolant loss are seen at  the moment.Then its highly likely to be the head gasket.Also check your fan is working and is coming on and off at the right time.May be the sensor or fan switch as its called.Running the A/C constantly will also make your engine run hot especially in the summer with the hot temperatures.