My Car is Overheating in Traffic

I had a coolant leak which was determined to be the water pump. I drove the car for a couple months just making sure to add coolant every few days not a bad leak and I had the water pump and thermostat replaced. However the car is now suddenly overheating.

Mostly when stopped, low speeds or any time you turn on the AC. When I tried to check the fan I noticed that the fan comes on as soon as I crank it up. What can cause the car to be overheating and why is the fan staying on? Please help

Hey there

I would first make sure the radiator is completely full of coolant, which can be a little difficult to see on these vehicles. If you have to add more than a pint of coolant to the system, you probably have a leak somewhere that needs to be repaired. Also make sure there are no air pockets in the system that needs to be bled out.

When the engine is warm, you should not easily be able to squeeze the upper radiator hose together with your bare hands, if you can you have a leak or air in the system. Also the upper and lower radiator hoses should be about the same temperature when the engine is warm. If not, you have a restriction in the radiator, and a new radiator is in order….or you still have air in the system that needs to be bled out.

The fans should cycle on and off at idle speed, although if you have 2 electric fans one is for the a/c and will come on and stay on as the a/c compressor is on. The other fan will be for the radiator and should also cycle on and off as the engine heats up.

Here is a video I made about overheating that might help you narrow things down more.

Austin Davis

Posted in: Over Heating

About the Author:

Austin Davis, consumer car repair advocate. "Hi there! I love to help people solve their car repair problems and I hope my site was helpful to you today. Thank you for stopping by."
  • Austin Davis

    Yep you are correct Frank, have to start with the obvious things and rule them out as you go.

  • Frank

    Thinking first about a leak is maybe what happens to most of us, I had this problem with my old car and I could have bet my house it was a leak and it really wasn´t.

  • Austin Davis

    Charly, yep air pockets left inside the system from doing a major cooling system repair (like replacing a radiator) can cause problems and be hard to diagnose sometimes.

  • Charly

    I was having a similar trouble and after reading and watching your video I went ahead and checked for air pockets in the system, I bled them out and now my car doesn’t overheats in in traffic anymore, very good advice, I did it myself and saved the 500 dollars a mechanic wanted to charge me to check for a leak!!

  • Marcus L

    Usually when a car overheats I think about a leak as the most probable cause, thanks for pointing out the possibility of air pockets.