Okay so I have tried everything.

My car was overheating so I replaced the head gasket since it needed one anyways, but it is still overheating. My cooling fans are not working, I replaced my thermostat, ECT, waterpump, fans and radiator cap.

I'm a beginner mechanic and I'm so stumped. I replaced everything related to the cooling system, I even ran a jumper wire from my fan switch positive and negative and the fans turned on. I have no idea what to do next, only thing I haven't replaced is the radiator.

  • Do your radiator hoses feel hot? What condition and level is your coolant? Did you purge the air out of the cooling system after your repairs?
    – tlhIngan
    Oct 29, 2016 at 22:09
  • My upper gets a little warm but doesn't have pressure and my lower stayed cold my coolent I have bleed out all the air and my coolant is full to where it over flows with the car on and cap off Oct 29, 2016 at 22:27
  • I think you have a flow problem. Most likely, your radiator is obstructed. Drain it and give it a good flush. There are household cleaners that dissolve rust and lime and waterscaling, you may want to buy a gallon of that stuff and fill your radiator with it and let it sit for a few hours.
    – tlhIngan
    Oct 29, 2016 at 22:31
  • Okay I was think about doing that befor I change my radiator thanks for the help it's really appreciated I'll get back to you afterwords Oct 29, 2016 at 22:34
  • 2
    Not sure if this will work on your vehicle, but disconnect the temperature sending unit and see if the fans turn on then. A lot of cars will automatically cut in the fans if the sending unit is disconnected or if there is a disruption in the continuity between the sensor and the PCU. This will tell you if the PCU is operating the fans (if they cut in). Doesn't discount this if they don't, though. You said you tried to change out relays, but did you try to put a jumper wire in place of the fan relay? This will let you know they are working and the power circuit is good. Oct 30, 2016 at 0:27

1 Answer 1


I just had the same problem and changed tstat and still no fan would cycle on and off and yes over heat. Then I changed the thermoswitch which is next to thermostats which tells fan to come on when temp of water get high. I changed mine and it fixed the problem, fans will now cycle on and off automatically to cool radiator

  • 1
    Which car was this for?
    – Zaid
    Mar 7, 2018 at 8:24

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .