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I am going to post this on a couple of forums to see if anyone can help me.
I have an overheating problem which is unique. It started with a bad thermostat. Originally, the thermostat would get stuck and the car would start to overheat. Sometimes, when driving with the top down, you wouldn’t notice until the engine got pretty hot and an audible alarm starting going off. So I would pull over shut off the car for 5 minutes and then start back up and it would be fine. I knew eventually I would have to replace it. Well the day came when my wife was driving, it heated up and it would not cool down. So I bought a new thermostat and installed it. Now is when the a much more serious problem developed.
The car continued to overheat, only this time, I didn’t know it was overheating until I would see steam rising from under the hood, despite the temperature gauge showing normal. It got so hot that it melted several holes in the antifreeze overflow tank. I have DynoScan computer software which lets monitor all the parameters of the vehicle like the dealers do. I monitored the engine coolant temperature as it went while idling the car. After about 5 minutes, the temperature on the computer readout was 190 and continuing to slowly rise. Yet, the car gauge went from cold to the middle and remained there. After an additional few minutes, the temp continued to rise to 220. The car gauge stayed centered on normal. An additional few minutes later, the computer temp indicated 240 the car was visibly overheating yet the car gauge was still centered between C and H. I also noticed that the cooling fan never came on.
I shut the car off and allowed it to cool down while checked the cooling fan fuses and connectors. I also replaced both temp sensors (oil and coolant). Once cool, I restarted the car and repeated the test I was doing only this time, when the temperature reached 200, I bypassed the cooling fan microprocessor circuit forcing it to come on. The temperature stopped rising and came down a few degrees. I felt that I identified the problem as the fan microprocessor and ordered a new one costing me $300.00. Once received, I installed the fan system and repeated the tests and found that I still have the same problem.
I am now tracing the wiring back to the PCM to see if there may be a broken wire. Otherwise, I can only conclude that is the PCM itself and I will have to replace it at about $700. I don’t understand why the temperature gauge never rises past center. This is a simple analog meter and it should read properly. There are no schematics on this particular meter in any ford documentation. So I can’t tell if the gauge is getting stuck and preventing a signal from being sent to the computer allowing the fan to turn on or, if the computer has a problem and is not sending a signal to the meter along with the fan.
Anyone have any ideas? With respect to going to the dealer or a mechanic. I did. They told me I had a blown engine and needed a new one at about $4,000. I didn’t believe them and made them do a Hydrocarbon test proving the engine was okay. I will do it myself but I could use some help.
Thanks in advance. Sorry to be so long but I felt the history was needed to get the full picture. 2003 Tbird with 42,000 miles.
Bob
I have an overheating problem which is unique. It started with a bad thermostat. Originally, the thermostat would get stuck and the car would start to overheat. Sometimes, when driving with the top down, you wouldn’t notice until the engine got pretty hot and an audible alarm starting going off. So I would pull over shut off the car for 5 minutes and then start back up and it would be fine. I knew eventually I would have to replace it. Well the day came when my wife was driving, it heated up and it would not cool down. So I bought a new thermostat and installed it. Now is when the a much more serious problem developed.
The car continued to overheat, only this time, I didn’t know it was overheating until I would see steam rising from under the hood, despite the temperature gauge showing normal. It got so hot that it melted several holes in the antifreeze overflow tank. I have DynoScan computer software which lets monitor all the parameters of the vehicle like the dealers do. I monitored the engine coolant temperature as it went while idling the car. After about 5 minutes, the temperature on the computer readout was 190 and continuing to slowly rise. Yet, the car gauge went from cold to the middle and remained there. After an additional few minutes, the temp continued to rise to 220. The car gauge stayed centered on normal. An additional few minutes later, the computer temp indicated 240 the car was visibly overheating yet the car gauge was still centered between C and H. I also noticed that the cooling fan never came on.
I shut the car off and allowed it to cool down while checked the cooling fan fuses and connectors. I also replaced both temp sensors (oil and coolant). Once cool, I restarted the car and repeated the test I was doing only this time, when the temperature reached 200, I bypassed the cooling fan microprocessor circuit forcing it to come on. The temperature stopped rising and came down a few degrees. I felt that I identified the problem as the fan microprocessor and ordered a new one costing me $300.00. Once received, I installed the fan system and repeated the tests and found that I still have the same problem.
I am now tracing the wiring back to the PCM to see if there may be a broken wire. Otherwise, I can only conclude that is the PCM itself and I will have to replace it at about $700. I don’t understand why the temperature gauge never rises past center. This is a simple analog meter and it should read properly. There are no schematics on this particular meter in any ford documentation. So I can’t tell if the gauge is getting stuck and preventing a signal from being sent to the computer allowing the fan to turn on or, if the computer has a problem and is not sending a signal to the meter along with the fan.
Anyone have any ideas? With respect to going to the dealer or a mechanic. I did. They told me I had a blown engine and needed a new one at about $4,000. I didn’t believe them and made them do a Hydrocarbon test proving the engine was okay. I will do it myself but I could use some help.
Thanks in advance. Sorry to be so long but I felt the history was needed to get the full picture. 2003 Tbird with 42,000 miles.
Bob
Canadian Provinces, 8 European Countries, 3 Caribbean Countries, Countless National Parks and have attended well over 100 TBN Events since 2001 and counting. Best of all ... fabulous friends.
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