Q: Hot at idle and low when driving never stays in middle

asked by on October 12, 2016

Just replaced 3 freeze plugs and thermostat and radiator cap. Car won't hold stedy temp I have no leaks now and no heat maybe 2 min of heat then cool air.

My car has 167000 miles.
My car has an automatic transmission.

Hi. This sounds like the water pump is not circulating the antifreeze in the engine. When a water pump stops circulating the antifreeze as well as it should the car tends to run hot when it is at idle and cooler when you are moving because you increase the engine speed while moving causing the water pump to increase its speed. Another possibility is that the radiator is clogged and causing the flow of coolant to be restricted. I suggest you having a certified technician from YourMechanic come and diagnose your cars overheating condition to avoid any necessary repairs.

Was this answer helpful?
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

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

Car overheats; coolant leak

If the engine got hot enough to cause a head gasket failure then all of these other parts must be replaced with it. I typically do a block test to verify that the head gasket is bad. If it is...

I'm ready to buy a 2004 Chevy Silverado but chk engine light shows Knock Sensor. Also Oil Pan Leak, Fr Axle Seals Leak. Buy? Cost?

Hello Mike. You have found yourself in a position where there is a lot to consider, and the choice is going to come down to how much risk you are willing to take with this truck. Starting with the knock...

Car steaming and leaking radiator fluid

I’m not sure what repair was done, but it sounds like a coolant hose was left loose. Do not drive the car with a major coolant leak. It will overheat very quickly. If the shop is a reputable one, they...

Related articles

How Long Does an AC Compressor Last?
As long as your car is running the way it should, you probably don’t even think about all the parts that are working...
The Best Used Cars to Buy If You’re a Plumber
Plumbers Plumbers need to carry around all manner of tools and supplies. If you’re plumbing a large building, or even a decent sized home, you’re going to need a vehicle that has quite a bit of cargo capacity. A car...
How Long Does a Heater Control Valve Last?
Keeping Keeping the right amount of coolant in a car is essential in keeping the engine at the right temperature. Failing to have the right amount of coolant or even bad elements of the coolant system can lead to a...