Skip the auto shop - Our mechanics make house calls

Q: AC blowing hot air

asked by on

Hi,

I have a 2005 Mazda 3. The AC is not blowing cold air at all. So initially I figured there was a leak somewhere on the system. I used UV Dye and found out that the condenser was leaking out the refrigerant. I bought a new condenser replaced the old one to find out that the "new" condenser was faulty (leaking out the refrigerant).

Now I returned that condenser and changed it yet again when putting the refrigerant in it is not blowing cold air. Decided to take it into a shop. The mechanic there said that the compressor was bad. So I went ahead and purchased a brand new AC compressor. The mechanic changed it car still not blowing cold air. When looking for leaks there are none that is visible. The mechanic at the shop said the high side is holding the pressure but the low side is not holding the pressure, but it keeps taking in the refrigerant but no visible leaks. He has no clue what is happening.

Any ideas as to why the AC is not blowing cold air with a brand new condenser and compressor ?

My car has 155000 miles.
My car has an automatic transmission.

Hi there. The high and low pressure sides of the A/C system are connected. The A/C system is a loop. It will not only leak from the low side but retain pressure in the high pressure side.

You make no mention whether the receiver/dryer was replaced either when the condenser(s) were replaced or when the compressor was replaced.

Whenever the A/C system has a leak, not only does the refrigerant leak out, but normal contamination and moisture in the air gets into the A/C system through that leak. Any time the A/C system has a leak or is opened for any length of time, either because of a leak or because the system was opened to replace parts, the receiver/dryer must be replaced. It’s job is to absorb contamination and moisture.

To explain how sensitive to moisture a receiver/dryer (otherwise known as an expansion tank) is, if a new one was laid out in the open on a humid day, within 30 minutes it would have absorbed enough moisture out of the air to render it useless. If that dryer is bad, it will affect the pressure readings between the high and low sides, and effect how cold your air gets. Too low or too high pressure readings can also be caused by a clogged expansion valve. If neither of those components were replaced when the A/C system was opened, start by replacing them both and recharging the system.

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!

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: High fuel consumption and the scanner cannot read the O2 sensor(Bank1 sensor1, on the neck of the exhaust line)

The problem sounds like you have a scanner that is not totally compatible with your vehicle. You may need to try a different scanner to see if the new scanner can access the computer data stream to monitor the fuel...

Q: Air conditioning slow to work

Hello. It sounds like your vehicle may be low on refrigerant. Performing an AC performance test will determine the cause of your problem and check the system for leaks. This test involves hooking up a set of gauges to check...

Q: Misfiring Cylinder after replacing the plugs three months ago. Is it a chance that the whole batch of plugs may have been defective?

Hi there. The best thing to do is switch the coil over from cylinder 3 to cylinder 1 and see if the misfire continues with cylinder 3 or if it changes to cylinder 1. If the misfire stays with cylinder...

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...
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...
P2103 OBD-II Trouble Code: Throttle Actuator Control Motor Circuit High
P2103 means there is a fault with the throttle actuator control motor circuit, likely due to a defective electrical component or part.