Cooling Issues
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Joined: Jun 2010
Posts: 72
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Cooling Issues
Ok, so I need to figure out if there's anything a backyard greasemonkey like me can do to solve an overheating problem I'm having... Here's the issue: A/C on: Fans run all the time, temp stays around 200° or thereabouts. Turn off the A/C and drive around town, it will continue to climb indefinitely, until I turn the A/C back on.
I looked in the FSM, hoping I could just replace a faulty thermoswitch and be done with it... NOPE! The manual lists 3-4 things that can cause the fans to come on, first the primary, then the secondary. 1) coolant temp, 2) Oil Temp, 3) A/C line pressure, and 4) if there is an error code stored in the ECM.
Nothing I read described my situation exactly and I don't want to just throw $$$ at it if I can avoid it. A/C on, fans on. A/C off, fans OFF, no matter the temp outside, no matter the coolant temp, etc...
Any words of advise???
I looked in the FSM, hoping I could just replace a faulty thermoswitch and be done with it... NOPE! The manual lists 3-4 things that can cause the fans to come on, first the primary, then the secondary. 1) coolant temp, 2) Oil Temp, 3) A/C line pressure, and 4) if there is an error code stored in the ECM.
Nothing I read described my situation exactly and I don't want to just throw $$$ at it if I can avoid it. A/C on, fans on. A/C off, fans OFF, no matter the temp outside, no matter the coolant temp, etc...
Any words of advise???
Instructor
Joined: Jul 2008
Posts: 218
Likes: 0
From: Utah County Utah
It sounds like a coolant sensor. You should be able to unplug the wires going to the sensor and measure the sensors resistance. I believe it should be around 2.5k if the engine is cold, and around 200 ohms once the engine is at running temp. You don't need the values to be exact, as long as they are somewhat close to those values.
If the sensor is bad, most likely you would just get nearly zero resistance, or infinite resistance.
If the sensor is bad, most likely you would just get nearly zero resistance, or infinite resistance.
Melting Slicks
Joined: May 2010
Posts: 2,082
Likes: 3
From: Conowingo Maryland
I am assuming that in town you are talking about low speed stop and go traffic. And also assume at highway speeds your temps are right about the 200 or so mark. how high have you seen the temps go? I am not 100% sure on your year but I think the cooling fan kicks in around 238. If your cooling fan is not kicking in right around there you need to check the temp sensor and wireing to it from the relay. you may reach a little over 240 before your temps drop after the fan kicks in. If in fact I am correct for your year that the fan kicks in around 238.
