Skip the auto shop - Our mechanics make house calls

Q: Engine fan continues to run, Check Engine light on, and coolant leaks.

asked by on

Engine fan comes on about eight seconds after the car starts and won't go off. The temperature gauge stopped working and the Check Engine light came on. Coolant is also leaking from the engine. I changed the coolant sensor, but nothing changed.

The two engine fans are controlled by separate relays that are turned on by a powertrain control unit. The system is controlled through the body control module that signals the powertrain control unit. The body control module gets signals from the cooling system and the air conditioning to turn the fan on and off. The complete system would need to be checked but I would recommend you get the coolant leak checked first by a certified technician. They would need to scan for codes, pressure test the cooling system and check the cooling system sensor or wiring problems.

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!
  • Home
  • Questions
  • Engine fan continues to run, Check Engine light on, and coolant leaks.

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: Truck not starting after sitting

Hi there. It sounds like you may have a battery reaching the end of its life cycle. Over time, batteries will lose their ability to hold and keep a charge. Typically between 7 and 10 years depending on the environment...

Q: Code p0128

Your vehicle does not have a coolant sensor and uses the cylinder head temperature sensor to do both jobs. The system uses this sensor to sense both the coolant and head temperature. If your vehicle fan is running all the...

Q: Check Engine Light is on - 2009 Chevrolet Malibu

If you have codes to a sensor, it does not always mean the sensor is bad. There may be wiring or connector problems causing erratic or incorrect sensor input to the computer. The code stored in a computer is only...

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...
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...
What are the Car Pool Rules in Hawaii?
Hawaii is widely regarded as a land of vacation and relaxation, and as such, its scenic roads and routes are far better known than the state’s freeways. But, as with all...