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Q: Overheating

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Hi .i have 2007 trailblazer causing overheat problems Changed water pump,thermostat, cleaned radiator,head gasket replaced Now car is getting overheat when ac is on Mechanic is now telling to replace fan clutch as the rpm is around 700

Please guide me in this issue .how much is the normal rpm of radiator fan Hope reply asap

My car has 100000 miles.
My car has an automatic transmission.

A: Let's go over the basics to be sure not...

Let's go over the basics to be sure nothing has been overlooked.

  • Verify the actual temp at the thermostat housing and compare it to gauge position when hot.
  • Make sure the cooling system is full of 50/50 Dexcool and distilled water.
  • Ensure that the system and cap have both been pressure tested and do hold pressure with no leaks.
  • No evidence of coolant in cylinders (inspect spark plugs).
  • No evidence of combustion gasses in cooling system.
  • All ducts and seal present around radiator and fan.
  • Air deflector still present under front of vehicle to direct air towards radiator.
  • Condenser fins are not excessively dirty or bent.
  • You are due for a belt and belt tensioner replacement due to mileage if it hasn't already been replaced.

Your Trailblazer will set a diagnostic trouble code (DTC) in the computer if it overheats. If engine coolant temperature is fine at cruising speeds and it overheats only in slow, or stop and go driving, you have an airflow problem. Then the electro-viscous fan should be suspected, diagnosed, and replaced if bad. If your mechanic is testing the operation of the computer-controlled fan clutch, which can be controlled with a scan tool, it sounds like he may be on the right track. If you'd like to have this checked out by another set of eyes, consider a qualified mechanic who can performs these checks and diagnose your overheating issue at your own convenience.

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