I'm driving a 1979 245 Wagon. All of a sudden, this past week, the needle in the temp guage has risen almost all the way to the top. It stops just short of the "red" zone, maybe a needle's width away but never goes any higher. My first thought was the thermostat, but a new one didn't solve the problem. Driving with the heat on doesn't bring down the temp either. There are no leaks and the coolant is up to the proper level. There are no unusual noises either when driving. I have been suggested to put a cooking thermometer in the coolant to be sure that it really is overheating but where should I stick the thermometer. There is no cap on the top of the radiator. In the fliud resevoir? Do I need a special temp guage? Any other ideas?

Phil - Vancouver WA

P.S. As this is my first visit, I must say that this site is a life saver. I've had 3 other of my questions answered by looking through the archives before this posting. Thanks to all who frequent these pages!!

I had a similiar problem where the car would overheat at random times. It would never go into the red zone but just below. I replaced the thermostat and later the radiator with no improvement. What finally fixed the probelm was replacing the water pump. The water pump had approximately 200k miles. There were no signs that the water pump had gone bad other than the random overheating. It did not leak and the bearings were still good.

I hope that helps.

B Gouveia

Go to Radio Shack and get a 100 ohm resistor, any wattage they have. Remove the wire from the sending unit on the cylinder head and put the resistor between the guage wire and ground. The guage will read in the center of its travel if the guage and volt stabilizer are good. This will also work for testing fuel guages.

Ok I'll try this too. Sounds easier than messing around with a cooking thermometer to test the accuracy of the guage. So if its not reading in the center, the problem is either a faulty guage or voltage stabilizer and if it is reading OK, then I'm overheating and should look elsewhere in the cooling system.
Thanks

Just curious--did the fuel gauge start acting up at the same time the temp gauge did. I had a simlar problems and it was an IC voltage regulator(5V) located behind the gauges. Part was cheap and relatively easy to fix. I had help troubleshooting from the good folks on this brick board and thats where I found my solution--hopes this helps--its an easy fix-check this before spending money on cooling related parts--been there and done that--good luck

Now that you mention it, the fuel guage has been giving weird readings lately. Thanks, I'll check it out today. Easy enough before I get too deep into it.