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: Intermittent whistling sound coming from front of car

Hi there: The sound you're describing is very similar to a serpentine or drive belt that is beginning to show signs of being loose or damaged. As the belt progressively gets looser, this noise will become more noticeable until it's...

Q: Previous owner had a fender bender in rear driver's side. The Service Parking Assist light is coming on. What do I need to do?

The Parking Assist warning message may simply mean that the sensors in the rear bumper are dirty, covered by a bumper sticker, or they are damaged. Wipe the sensors with a wet cloth or paper towel. Drive forward at...

Q: Car always struggles to start on cold start ,it is not the battert i just bought a new one

As a general rule, car engines do not like cold weather and do not do operate as well in cold weather. When you start your vehicle in the morning and turn the key to on, the coolant temperature sensor reads...

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...
P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...
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.