Skip the auto shop - Our mechanics make house calls

Q: Having problems with temperature gauge

asked by on

My car normally runs perfectly, but if it sits still for a few minutes, the temperature gauge goes up and I get a warning light. If the car is moving, the gauge is normal. If I turn on the heat full-blast, the gauge drops to normal. It hasn't actually steamed up yet or given any other indication, but when I catch it happening I either turn the car off, or turn on the heater. The car is due for an oil change, but the level is fine and it doesn't look terrible. The coolant was low. I can't really say how low exactly, but about the capacity of the reservoir. However, adding coolant hasn't changed anything. Also, I haven't caught it leaking anything yet. The radiator fans are running. I don't know if this could be relevant, but this has been happening more or less since I recharged the A/C. The A/C hadn't been working for almost as long as we've owned the car, about three years. But turning the A/C on or off makes no difference. Any ideas?

A: The only way to determine the root cause of...

The only way to determine the root cause of your problem is to have the vehicle's warning light inspected firsthand by a professional, such as one from YourMechanic.

An engine that is running hot is less likely to overheat when it is moving because cool air is being pushed through the radiator at the front of the vehicle. Likewise, turning on the heater draws heat out of the engine compartment and into the interior of the vehicle.

The first thing that comes to mind is the engine cooling fan, since a failed fan would be the most likely cause of a vehicle that overheats at idle, but not while moving. But since you said the fan is working, I would look at the water pump next. Since it is driven off the engine, the water pump flows more at higher RPMs. This is just a guess though, and really, any part of your cooling system could be to blame.

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・Save up to 30%

Get a quote

What others are asking

Q: CD changer locked open.

The CD changer is equipped with a mechanical motor that opens and closes the loading mechanism. Over time this plastic motor either strips out or just stops working. There are some electronic rebuilders available that can repair this unit, but...

Q: Air conditioner not cooling as much.

The AC hose you had replaced may be leaking or the mechanic may of under or overcharged the AC system at the time of service. Another problem may of surfaced and it took three months to leak down to the...

Q: My car overheated with smoke coming out, I found antifreeze all over the engine and the temperature gauge was high

This can be caused by a number of things such as low coolant levels, a faulty thermostat, or a failing coolant fan switch. As you may know, the coolant fan switch helps to maintain the proper coolant temperature by turning...

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...
Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...
How Much Does a Mechanic Make in Vermont?
Automotive technician jobs in Vermont have an average mechanic salary of $37k, with some mechanics earning a salary of $53k.