Q: My 2008 Honda Accord blows hot air and the ac make Lois humming noise

asked by on

We just bought a 2008 Honda Accord about a month ago. We noticed that when the ac is on, the car has a loud humming noise. Once you turn off the ac the sound stops. Last week, our ac started blowing hot air. We bought a DIY ac recharger but it wouldn't in take any of the product, the vavle stayed on the red area.

My car has 137000 miles.
My car has an automatic transmission.

To determine the exact fault, the system will have to be tested. You can obtain that service by requesting an a/c system diagnostic. If the a/c switch was set to "on" and you attached a can of refrigerant with an integral color-coded gauge, the reason the gauge displayed in the red (overcharged) zone is the compressor was not on (that’s an indication of the fault by the way; for some as yet undetermined reason your compressor is not coming on). What happens when the compressor is NOT on, is the LOW side pressure is actually way, way above that expected during normal re-charging. So, when you attach that gauge to a non functioning system the gauge necessarily reports the pressure as "off-scale" high (red). A functioning system has a LOW side pressure of roughly 35 PSI (high side could be in the neighborhood of 200 PSI) while, again, when the system is off, or not functional, low side pressure rises to a static value of roughly 70 PSI.


At any rate, the experience you are reporting with the recharge can suggests your compressor is not turning on. The noise you are reporting could be caused by faults in a lot of different a/c related components: the condenser fan, the passenger compartment blower, the compressor clutch, or the compressor itself. Your system has at least a partial charge so what the mechanic will likely do initially is turn the compressor by hand (with the car OFF) to see if it is seized. If it is not seized, and yet when the A/C switch is in the on position, there is no power to the clutch, that circuit has to be diagnosed. On the other hand, if there is power to the clutch, but no clutch operation (the a/c clutch mates the compressor itself to the drive pulley), then you need a new clutch. There are other checks that will be performed, if necessary, but the bottom line is if you request the diagnostic, the mechanic will pinpoint the fault for you and get this resolved. It is probably a reasonably circumscribed fault. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.

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. My 2008 Honda Accord blows hot air and the ac make Lois humming noise

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: Air conditioner blows hot air. 1995 Mercedes-Benz E300

Hi there, thanks for writing in about your 1995 Mercedes-Benz E550. This could be a variety of issues, such as no pressure or low refrigerant levels, a bad compressor clutch, or a compressor not engaging correctly. Check to see if the...

Q: Hit a Curb 2016 Honda Accord

Hello - this task is best handled by a collision repair estimator at a reputable paint and body shop. S/he is trained to evaluate visible and not-so-visible damage, and the costs to repair. Contact a reputable paint and body shop...

Q: Q: Car wont start

The problem you are having may be the EIS ECU not turning on intermittently. There is a technical service bulletin from the manufacturer dated 11/29/2012 and the number is LI80.57-P-053608. You will need to dealer or a mechanic that has...

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...
P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the...
Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...