Q: Strange whirring noise coming from the engine

asked by on

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.

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. Strange whirring noise coming from the engine

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: Motor has a tapping sound at idle, gets louder as you rev higher.

A light tapping noise from the engine may be caused by a low oil level as there isn't enough oil flowing through the engine. Louder clacking and knocking noises that sound like they are coming from the lower end of...

Q: My car's engine dies shortly after I put it into gear.

It sounds like you may have a dirty or failing idle air control valve. The idle air control valve monitors the air intake as it is mixed with fuel prior to being injected into the engine at low speeds and...

Q: The malfunction indicator lamp is lighted and we cannot start the engine.

A check engine light accompanied by a no start condition can often times be caused by a faulty camshaft or crankshaft position sensor. I would recommend having your trouble codes read with an OBD2 scanner to determine if these sensors...

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 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...
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.