Q: Can a bad thermostat cause me to have to keep putting coolant in my car?

asked by on

My car runs hot sometimes. The temperature guage will go all the way up and come back down to normal. Also I smell the coolant sometimes when I get out my car and I never had that problem before. On some days it runs hot but most days it is fine.

My car has 161000 miles.
My car has an automatic transmission.

Hi, thanks for writing in. The thermostat in the engine cooling system is a valve that opens and closes as engine temperature fluctuates. The purpose of the valve is to keep the engine operating temperature at a relatively constant, optimal level of roughly 200 degrees. Keeping it at that temperature maximizes the efficiency of the engine while preventing damage from too high a temperature. If the thermostat is malfunctioning, for example sticking, that could cause the car to overheat. The odor of coolant is probably due to very hot coolant overflowing into the reservoir, and perhaps even out of the reservoir, on those occasions when the engine is operating too hot. Overheating is not good for the engine. If severe, it can cause quite a bit of damage actually, including things like a warped cylinder head or engine block. If you are having to add coolant more than once or twice a year, you have a leak somewhere in the cooling system. If the engine is overheating, the best to do is get the cause identified and repaired. YourMechanic specializes in just that sort of diagnostic and would be glad to help you with this issue so that you can get your car repaired and running normally. Our technicians can come directly to your home or office to inspect your car for you.

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
  1. Home
  2. Questions
  3. Can a bad thermostat cause me to have to keep putting coolant in my car?

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: Fan belt squeaking

The belt tensioner or pulley will need to be checked along with the belt's condition. The belt may just need to be adjusted. I recommend having a certified mechanic, like one from YourMechanic, come and test your vehicle for you....

Q: Q: why does my car won't go into gear?

You should check and see with engine off if the clutch slave is moving the clutch when pedal is pressed. If it does not move or take a couple pumps to move then you either have air in system or...

Q: My car keeps running hot then it cools down

Hi, thanks for writing in. There are two possibilities here: either the physical temperature of the engine is indeed fluctuating significantly, or the sensor and/or circuit that feeds the temperature gauge is malfunctioning. The sensor (and circuit) can be tested...

Related articles

What Causes Hoses to Leak?
While the largest part of your engine is mechanical, hydraulics plays a significant role. You’ll find fluids at work in a number of different areas. Your car's fluids include: Engine oil Transmission...
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...
P2103 OBD-II Trouble Code: Throttle Actuator Control Motor Circuit High
P2103 means there is a fault with the throttle actuator control motor circuit, likely due to a defective electrical component or part.