Skip the auto shop - Our mechanics make house calls

Q: losse of heat when going 70.

asked by on

The heat works great up until around hitting 70mph, then it starts blowing cool air. The temp guage also drops. If you slow down, it goes back up and heat returns. Antifreeze is full.. Temp guage???

My car has 124000 miles.
My car has an automatic transmission.

A: Hi there. I have come across this same prob...

Hi there. I have come across this same problem several times. The majority of the time it is caused by a failing thermostat. Due to the poor design of a metal thermostat molded into a plastic housing these will not wear the same and the thermostat ends up sticking in the housing and no longer closing correctly. If this occurs, the coolant does not stay in the engine long enough to get hot, and will get hot under an increased load, such as going up a hill. I would typically change the thermostat first. If you needed to have this done, consider YourMechanic, as a certified mechanic can come to your home or office to replace the thermostat for you.

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

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: Power steering pump went out

While there are quite a number of reasons behind a power steering pump failing on your Jeep Liberty, from the information provided, it leads me to believe that there may actually be a serious leak in the power steering system....

Q: When the sky slider closes, should it push down on the seal when completely closed to prevent water from getting in?

Hi there. Check the sky slider cables and make sure that they are lubricated. The cables should be lubricated every couple of oil changes. This will allow the mechanism to operate smoothly and fully seal. If you need further assistance...

Q: I have a new thermostat, how much should it cost to change it out?

Billing question sent to CS for the cost to replace the thermostat on a 2010 Jeep Liberty V6- 3.7L.

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 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.