Q: Strange whirring noise coming from the engine

asked by on August 14, 2016

We recently drove to North Carolina and back, approximately 1400 miles. Before the trip, I replaced the blower motor and resistor under the dash, because the fan would only work on setting 4, and the blower was sounding bad. Everything worked great for about 400 miles, besides the a/c blowing semi cool air. After driving for many hours and stopping for lunch, we continued our journey. Shortly after, mist started coming from the cents and our semi cool air now, had become warm. Not hot, just not cool. I took it as the Freon being low or empty, so we turned the a/c off for the rest of the entire trip. When we returned home, I purchased a bottle with a gauge to recharge the system. I did not use the entire can, but still managed to overfill it. By a little research, I found I could bleed it. I bled very little, and the a/c was working great. After about 3 hours of driving, the warm air returned and a fairly loud whirring sound started in the engine. Sound stops when car is off

My car has 100000 miles.
My car has an automatic transmission.

It sounds like you are getting water built up inside the evaporator housing and need to unplug the A/C drain or you will flood the evaporator, blower motor, and resistor with water and short the motor and resistor again. If you’d like a local expert to check this out, a certified technician from YourMechanic can come to your home or office to inspect the A/C system and whirring noise in order to determine what fixes should be done.

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・Fair and transparent pricing

What others are asking

Why would there be smoke coming from under my hood and now my car does not shift 2001 Honda Civic

Hi there. It seems that the transmission fluid is leaking. Check the cooler hoses from the transmission to the radiator on the car and see if they are leaking. A leak on the transmission will cause the vehicle to not...

Car stopped randomly and didn't drive afterwards

Hello, thanks for writing in. The computer will go into a failure mode and may not allow the electronic throttle to open if it detects a major computer or sensor fault. There can be many possible failures that will cause...

Service traction control light

Hi, thanks for writing in. Your car is equipped with wheel speed sensors at each of the four wheels which monitor wheel speed while relaying this information constantly to the ABS and traction control system which are controlled by the...

Blower motor works sometimes

Your car has an automatic temperature control system and it sends signals out to the blower controller in the evaporator housing in the engine compartment. The blower controller is the most common failure along with the blower motor. The blower...

How do I use the engine block heater in a 2012 Dodge Ram?

The engine block heater helps heat up your engine during very cold weather. If your vehicle has the engine block heater, you should always use it when starting your car in extremely cold conditions. Here’s how. Locate the engine...

AC not blowing cold

You likely have two issues occurring at the same time. The fan operation is most likely due to an issue with your blower fan speed controller. It could also be the control assembly with the knob, or plug and wiring....

2005 Honda Civic standard. Brakes are engaging themselves while we are driving. The car slows down on its own, the rotors get all

If the brake master cylinder internal residual check valve sticks it will not let pressure release to the brakes and will cause brake drag. You should jack up suspect locking brakes wheel and if it will not turn then crack...

My car doesn't accelerate, overheats, makes a loud noise, and the brakes don't work.

Hello. It sounds like the engine may have major mechanical problems at this point. I do not have any information on the model of the vehicle or the type of noise, so a little more work will need to be...

What else can be making noise under the front of my 2013 Ford Explorer

Hi there. I have come across this situation with this vehicle a few times. Most of the time it is one of two things. It is either caused by bad strut mounts or by failing lower control arm bushings. The...

Related articles

P0539 OBD-II Trouble Code: A/C Evaporator Temperature Sensor Circuit Intermittent
P0539 means the A/C evaporator temperature sensor has a too high/low voltage signal, usually caused by a faulty evaporator temperature sensor.
What Typically Causes the Heating or AC to Stop Working?
While both the heating and AC are connected - to an extent - within your car, they’re actually...
How to Replace a Heater Blower Motor Switch or Relay
The motor switch on your heater and air conditioning goes bad when the switch gets stuck in certain positions or will not budge at all.