Skip the auto shop - Our mechanics make house calls

Q: Overheating

asked by on

Vehicle was overheating, noticed leak in radiator. I replaced radiator, thermostat, and the fuel filter since I was already working on the truck. The truck is still running at around 210-240 while driving, and climbs to 260 when stopped at red-light. What else could cause my truck to reach that temp?

My car has 180000 miles.
My car has an automatic transmission.

Hi There, I would recommend also checking the cooling fans to be sure they are coming on. A common problem associated with cooling fans is the relay that fails resulting in them not coming on to help cool the radiator at the correct times. As you may know the coolant fan switch helps to maintain the proper coolant temperature by turning on and off at specific temperature thresholds. When this switch is not working properly, this can cause the fans to come on intermittently, all the time or sometimes not at all. When this happens you will notice a temperature spike and drop occasionally as the fan comes on and off. The typical electric cooling fan circuit includes a temperature sensor, a relay, a control module and the fan motor. The relay is the component that fails most often, so be sure to test the relay as well as its power supply and ground connections. A good relay coil will typically read 40 to 80 ohms. If resistance is high, the coil may still be working but it is failing, or it may not work when electrical loads are high. If the coil has no resistance, it is open and has failed and you will need to replace the relay.

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・Fair and transparent pricing

Get a quote

What others are asking

Q: Warning light coming on

Are and of the gauges not acting like they normally do? On your vehicle a common failure is of the oil pressure sending unit. When this happens your gauge will display zero oil pressure and cause the check gauges light...

Q: What's the difference between welding catalytic converters in place and placing a sleeve with clamps on it?

Hi there. It is okay to replace a catalytic converter with using clamps and sleeves. However, you will need to make sure that there is no exhaust leaks. An exhaust leak before any oxygen sensor will cause the engine light...

Q: Leak at the top of the pinion gear. Not much, can smell the burning fluid. Use Lucas oil or replace the whole rack.

I would replace the whole rack and pinion. You could try a rebuild kit if you want but as a technician I would suggest getting a new one. If you would like to verify the cause of the leak before...

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.