Q: AC knocking when it is turned on
I think there is either a problem with the blower or fan belt. When the air conditioner is turned on, it starts making a catching/knocking sound. As soon as it is turned off, it stops.
Recommended Services
| Car surges when air conditioning is on Inspection | $94.99 - $114.99 | Get a Quote |
Hi there. It sounds to me as if your AC’s fan is interfering with something in the track of its spinning. Also your issue can point to your AC compressor clutch not gripping the pulley correctly. I’d suggest having a certified mechanic sent by YourMechanic come to your residence and correctly diagnose the air conditioner’s symptoms that your vehicle is experiencing.
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
Brake lights not working
The stop lamp switch most likely failed and is not making contact internally. The switch may need to be adjusted or replaced. I recommend seeking a technician, such as one from YourMechanic, to come and test your vehicle's brake lights...
My Kia Forte is making a grinding knocking noise when I put it in drive and accelerate and at about 5 mph and up it goes away unti
Hello. Exhaust systems can make a variety of sounds that we would not intuitively expect. When I was first learning about exhaust systems I was surprised to find out how dynamic they can be. I am assuming you are speaking...
Car anti-theft lite blink and it won't let my car start
Hello there, a few common faults will cause the security light to remain on and the car not to start. The most common is a worn key, faulty key transponder, security module failure, or a wiring harness fault. A qualified...
my truck feels like the rearend is going out
Hi There, If the brakes have been confirmed not to be the issue, I would recommend having the axle (https://www.yourmechanic.com/services/differential-fluid-service-rear-axle-oil-service-) inspected by a qualified professional. This would likely involve removing the fill plug to the differential to see if the...
When driving the car it feels like it's gone into a higher gear.
Hello, thanks for writing in. Is your Check Engine Light (https://www.yourmechanic.com/services/check-engine-light-is-on-inspection) illuminated? Your description sounds like your transmission may be in "limp mode" which is usually 2nd gear in many transmissions. It is also possible that the sensation you are...
My car won't move while it's in drive, 2nd or 3rd gear
Hello, this transmission is controlled by a computer. There are sensors for input information and solenoids are used to control outputs. What you describe sounds like an internal issue. If you'd like, a certified YourMechanic Technician can come to your...
What can cause intermittent cold starting fault?
This may be related to a cold start enrichment problem which is generally controlled by the coolant temperature sensor (https://www.yourmechanic.com/services/coolant-temperature-switch-sensor-replacement). This sensor relays the temperature of the engine coolant to the computer which then makes fuel adjustments based upon the...
What causes oil leak between head and block and whitish blue smoke from exhaust plus milky oil
This is a common sign of a blown cylinder head gasket. In between the cylinder head and block is a thick gasket that seals off the combustion chamber and maintains separation of the oil and water passages through the cylinder...
Car running below operating temp/ check engine light
Hi there. The code you've listed is commonly associated with a temperature control system failure - not necessarily a problem with the radiator thermostat. There are a few easy things you can do to begin the diagnostic process. Check the...
Related articles
2011 Dodge Ram vs. 2011 Ford F-150: Which One Should I Buy?
Large trucks can be fun to drive, and even more fun to get dirty. Unfortunately, they may also cause you to get phone calls from friends who need to move into a new apartment. Fortunately, just having a truck may...
How to Replace an Air Conditioning Belt
Replacing an AC belt can be challenging, as you have to locate specific parts in the car in order to do so, and use proper tools to complete the task.
Top 10 Best-Selling Cars of 2016
Ford F-series pickup trucks, Toyota Camry, and Honda Civic are some of the best-selling cars of 2016 and all deliver on reliability and efficiency.
Browse other content
Estimates
Maintenance