Skip the auto shop - Our mechanics make house calls

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

asked by on

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?

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: Changed bypass hose now engine overheats

Hello there, a few common faults will result in your 2003 Hyundai overheating after the bypass hose was replaced. The most common would be air trapped in the coolant system. This is common after repairs have been performed if the...

Q: Tranny & Power Steering Flush

According to Mitchell Prodemand, the manual transmission on this vehicle holds 1.2 quarts. The power steering fluid should take 1-1.5 quarts. I would recommend checking your owners manual in the maintenance section to verify that these capacities are correct. The...

Q: Where is thermostat located in 2006 DTS

The thermostat is located inside the water outlet housing fastened to the upper radiator hose. The thermostat is on the engine side of the hose. If you need some help with this repair, consider hiring one of our mobile experts...

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...
How Long Does a Distributor O Ring Last?
The distributor is part of the ignition system in your vehicle and its purpose is to route high voltage from the ignition coil to the spark plug. The spark plug then...
How Long Does a Heater Control Valve Last?
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...