Skip the auto shop - Our mechanics make house calls

Q: Overheating

asked by on

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.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Save up to 30%

Get a quote

What others are asking

Q: Fuel gauge and tank not holding enough

The most common problem is the fuel pump sending unit is bad in the fuel tank. The fuel gauge may also be bad in the dash. The best and quickest way to test the gauge is to disconnect the connection...

Q: noise from front side of driver seat

Hello. If I had a description of the noise it would help me to diagnose what the noise is. On a Toyota Corolla, there are common issues with the engine mounts that will cause noise as well as a failing...

Q: My car make a winning sound when I accelerate the engine

Hi there: A whining sound that occurs while you're engine is accelerating is commonly caused by a worn out or loose drive or serpentine belt that needs to be replaced. In some cases, the belt will become loose because the...

Related articles

How Do Power Car Windows Increase Passenger Safety?
Power windows are responsible for approximately 2,000 emergency room visits every year. When a power window closes, it exerts enough force to bruise or break bones, crush fingers, or restrict an airway. Though...
P2428 OBD-II Trouble Code: Exhaust Gas Temperature Too High Bank 1
P2428 code definition A P2428 trouble code signifies that the PCM has detected a problem in the exhaust gas temperature sensor circuit in bank 1, which subsequently contains the number one...
P2103 OBD-II Trouble Code: Throttle Actuator Control Motor Circuit High
P2103 means there is a fault with the throttle actuator control motor circuit, likely due to a defective electrical component or part.