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Q: Vehicle is starting to overheat at idle.

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Hello there. My Silverado has a cooling issue when sitting idle. If left for too long it begins to overheat with the temperature climbing steadily towards 235 and in a matter of no time, if left unattended for too long, will reach 260 (I have only done this once. Shut the truck down every time I leave it now). When driving down the road, the temp starts right at it just a hair below 210. When sitting at idle for lengths of time, as long as the heat is on full blast, it will just go past 210 reading in between the second and third line. I'm trying to determine if this is a failing fan clutch, thermostat, water pump or some combination of the 3. I have a degree in auto but have never been faced with this sort of issue. I'm not one to just throw parts at a vehicle either. I want to do the job properly and not have any other issues or unnecessary expense. Thank you in advance for your time and response on the issue.

My car has 157000 miles.
My car has an automatic transmission.

There is a technical bulletin TSB 04-06-02-006A that covers the issue you are getting. It states that the cooling fan clutch will disengage at lower rpm’s of the engine and will allow the engine to overheat. You should replace the cooling fan clutch with the new design that engages at the lower engine speeds and temperatures.

You may have to supply vehicle VIN to get the correct one for your motor. There are a couple different dealer parts listed depending on the motor ID you have. There may be aftermarket parts on the market but I cannot tell you if they will fix the problem you have.

If you’d like assistance with this, YourMechanic has mobile technicians readily available to diagnose your overheating issue and service your fan clutch if necessary. Best of luck.

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