This is in regard to a 1995 Caravan with a 2.5L 4-cylinder engine.
I have done a lot of work on this van recently (discussed in another thread) and now it is running great, and no leaks anywhere that I can see. However, one problem has apparently continued, which is that approximately once every 15 to 20 times that I drive the van, I see what I assume is a false overheating condition.
What will happen is that the engine temperature gauge will start creeping up over a period of 1 to 3 minutes, get to the tick mark just under the maximum, then the "check gauges" light comes on, and an alarm sounds. It will stay there for a minute or two, then it just drops back to the normal position, which is just below the middle tick mark.
Since I don't believe that the engine could really overheat that fast, and certainly if it was overheated, it wouldn't cool off to normal so quickly, I assume this is a wiring or computer issue? I have already replaced both coolant temperature sensors, and I used the MotoRad thermostat which has a small orifice to allow a small amount of coolant flow at all times, even when the thermostat is closed. There is no evidence of air or other gases in the coolant lines or radiator. There is no loss or contamination of the oil or coolant, either.
Any ideas? Is this something that a shop with the factory scan tool could pinpoint, based on information stored in the PCM? This is a very intermittent problem, i.e. I could take a 50+ mile round trip with mixed freeway driving and city driving and not see it, and then it could happen on a short 2-mile trip to buy groceries. It has happened while driving at speed on a freeway, it has happened while driving in stop-and-go traffic, and it has even happened while idling at a busy intersection.
I have done a lot of work on this van recently (discussed in another thread) and now it is running great, and no leaks anywhere that I can see. However, one problem has apparently continued, which is that approximately once every 15 to 20 times that I drive the van, I see what I assume is a false overheating condition.
What will happen is that the engine temperature gauge will start creeping up over a period of 1 to 3 minutes, get to the tick mark just under the maximum, then the "check gauges" light comes on, and an alarm sounds. It will stay there for a minute or two, then it just drops back to the normal position, which is just below the middle tick mark.
Since I don't believe that the engine could really overheat that fast, and certainly if it was overheated, it wouldn't cool off to normal so quickly, I assume this is a wiring or computer issue? I have already replaced both coolant temperature sensors, and I used the MotoRad thermostat which has a small orifice to allow a small amount of coolant flow at all times, even when the thermostat is closed. There is no evidence of air or other gases in the coolant lines or radiator. There is no loss or contamination of the oil or coolant, either.
Any ideas? Is this something that a shop with the factory scan tool could pinpoint, based on information stored in the PCM? This is a very intermittent problem, i.e. I could take a 50+ mile round trip with mixed freeway driving and city driving and not see it, and then it could happen on a short 2-mile trip to buy groceries. It has happened while driving at speed on a freeway, it has happened while driving in stop-and-go traffic, and it has even happened while idling at a busy intersection.