By October 27, 2008 Read More →

Why is My Car Over Heating?

Hello Mr. Mechanic! I’m hoping you’ll be able to help me out. I’ll give you the scenario and maybe you can help with telling me what might be wrong.

Two weeks ago I replaced my water pump, my thermostat, changed my oil and refilled my coolant tank with coolant/antifreeze. What prompted all of that was my assumption that my thermostat was sticking. I had plenty of coolant and wasn’t sure why the temp guage would go into the ‘danger zone’ causing my check guages light to come on. After about 10 minutes of driving the needle dropped the gauge light went off, it was all good. That’s when I changed my thermostat just to be on the safe side.

As long as we were in the engine we replaced the water pump as well. It had been acting up a few mnonths prior and I bought a new one. I didn’t replace it right away because the squealing noise stopped. Yesterday and today I’ve been having temp gauge problems again. Yesterday it happened when I drove my car to work and then drove my car home. The gauge would rise and steady itself in between the danger zone and the normal zone, no gauge light. After a few more minutes the needle would sit in the danger zone for another 5 or 6 minutes, guage light on. Again after another few minutes the needle dropped, light went off, all was good.

Today’s what got me… started my car up to drive to work. On the way to work, the gauge sat as it did before, right between danger and normal for about 6 minutes. After that the needle went into the danger zone and was there for another 6 minutes. At the end of that 6 minutes I slowed to turn onto the highway ramp, my car had no get up and go it was in a lull I freaked out, I mean wtf ?! I proceeded to creep down the ramp and as I stepped on the gas a little more the needle dropped and my car went flying down the ramp…. The remaining 3 minutes of my drive was fine, gauge was at normal.

While the gauge is up and in the danger zone I have cold air. Once the gauge drops to normal, there’s the heat. What the heck… really.. I need your help telling me what might be wrong.

Thanks SO much !!


Hey there Angie,

Did you read my overheating article?

Engine Overheating

I can only highly suggest that you get a cooling system pressure test
FIRST before you do anything else. it sounds like this is either a
restriction in your radiator, or there is an air pocket in the system
that needs to be bled out, or you have a coolant leak somewhere which
the pressure test should uncover.

When the engine is hot, feel the upper and lower radiator hoses….they
should both be about the same temperature. If the top is much hotter
than the bottom, most likely your radiator is restricted at the bottom
with rust or dirt etc. etc.

You have cold air coming out the vents because there is NO hot
antifreeze circulating throughout the system. the heater blows hot air
because the heater core has HOT coolant circulating through it. the
heater core is like a small radiator inside the dash of the vehicle.

here is more info on the heater just so you understand how it works.

Car Heater Not Working

Keep me posted as to what you find out.

Austin Davis


Hey there Austin,

Thanks for getting back to me. I did in fact read over the articles…
They were very helpful. I ended up taking my car in that very next day
and it was in fact an air pocket in my cooling system. They bled it and
all is fine…. The only thing they suggested was next time around I
need to change my lower intake manifold gasket… But since it’s an
expensive job, I’ll hold off ;)

Thanks again !


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."

Comments are closed.