A/C starts off cold then blows warm

ladybinks · Post by **ladybinks** » 09 May 2010, 14:28

The a/c starts off cold and within 5-10 minutes the air is coming out luke warm. I shut it off for 5 minutes and turn it on again and it blows cold for a few minutes. It will blow cool when the weather is cool. When the temp outside is above 70 the above cycle continues. I have taken it to the dealership and they say that the diagonics show nothing. I am at my wits ends. I know that something is wrong. Will you help. Please.

Post by **JDS60R** » 10 May 2010, 10:02

I am going to assume the AC switch is on, the temp is set to max cold and the fan is on.

If the dealer is correct that the cooling sytem is working it would come down to your climate control unit.
The AC can be cooling the evaporator coil perfectly but the cliamte control is routing air through the heater or mixing enough heated and cooled air to not give you the cooling effect.

In older cars the doors the cliamte control closes and opens were controlled by vacuum actuators. If your car has one it could be failing ( or the vacuum hose to it is failing. This is ofdten missed as the car is usually idling at the dealer which gives lots of vacuum while driving it provides less ( car makes most vacuum at idle) . So its the vacuum line, the switch or the actuator.

If the climate control doors are electronically actuated then a technician will have to diagnose what is going on. Or you can check under the dash to see what is happening.

When it feels warm does the compressor still turn on and off? Can you hear the cooling fan on the radiator turn on and off?

Post by **kdaide** » 16 Jun 2010, 10:06

Was a solution ever found for this problem?

I have the exact same problem with my 2002 S60 T4 AWD. It blows nice and cool and after some time turns warm. When this happens, there is no differece between the tempurature of the air whent he A/C button is on or off.

If I turn the A/C off for 5-10 minutes and turn turn it back on, the air is nice a cool again; however, not for as long.

The time it remains cool seems to depend on how hot it is outside. On cooler days, it can run cool continouslty.

--Kevin

Post by **billofdurham** » 16 Jun 2010, 12:36

We didn't get an update on this so unfortunately we don't know.

Does your AC need a recharge?
Is the engine cooling fan switching on as soon as you switch on the AC? As the compressor pushes the gas through the condenser the engine cooling fan helps to turn the gas back into a liquid which is then fed into the evaporator as a spray. It is this spray of liquid which absorbs the heat from inside the car, turns back into a gas and goes to the compressor to be shoved round again. If the radiator fan isn't doing its job or the condenser is partially obstructed then the AC won't be working at full capacity.

Bill.

Post by **kdaide** » 16 Jun 2010, 12:54

Bill-

I took the car to the garage and they said that is needed a little more refrigerant so they added some plus a sealant. It seems to have help a little although it hasn't been as hot around hear lately and that has an impact on performance.

I think that engine cooling fan is working as expected because if the turn off the A/C using the button the air pressure coming from the vents is reduced. Turning on the A/C using the button does the oppsite, as expected.

I'm taking it back in the garage on Friday. A couple of years ago, the garage accidently over pressurized my system and it showed the exact same behavior. The solution for this was simple, remove some of the 134a. It seems that my car's A/C is very senstitive to the pressure.

Do know what the pressure should be on both the high and low sides?

Thanks for you help

-Kevin

Post by **billofdurham** » 16 Jun 2010, 15:50

The best way to check for the engine cooling fan working is to switch on the AC and look to see if the fan has kicked in.

The pressures - High side 406-464 psi; Low side 25.4-32.6psi.

Bill.

Post by **kdaide** » 16 Jun 2010, 19:41

Bill-

I checked the cooling fan and it kicks in when the A/C is turned on and then goes off shortly after the A/C is turned off so that doesn't seem to be the problem

If you have any other ideas, i'd love to hear them

Thanks for your help so far

--Kevin

2002 S60 2.4T AWD 220,000kms

gilsfour · Post by **gilsfour** » 28 Jun 2010, 15:02

I have a 06 S40 which would cool great and then quit. If I turned off the A/C switch and turned it on again in a few minutes, it would cool again but not for as long a time period. These symptoms seem similar to what has been experienced in this thread.

Here's what I found had happened. The electric clutch on the compressor had worn enough that the coil would not engage the clutch when the unit got hot. I could take a pry bar and "help" engage the clutch by pushing in on the clutch. Then the clutch would stay engaged for a while. When it kicked out again, I could help it engage again, but it would not engage on its own.

This test method at least told me there was no electronic control or internal problem.

I went ahead and installed a new compressor with new clutch.

Gil

S40Tex · Post by **S40Tex** » 13 Apr 2011, 08:14

I think i have the same problem as you, gilsfour. This problem started last summer when it would be 95+ out and i was driving on the highway with the A/C on. It would be great for the first few minutes, then no cold air anymore. The warmer air that started blowing through the vents even smelled a little different. Over the fall and winter i never had the problem. Now, if it even gets into the high 70's and i'm just driving around town it happens. I've read around on other forums, and on this one and i think the clutch is the issue. I've heard though that since my car has over 110,000mi on it that it's only a matter of time now before the A/C Compressor dies also, so i may as well replace it, like what you (gilsfour) did.

In Houston there is a Pick-A-Part place that i'm going to this weekend where i'm gonna try and find a good A/C Compressor. However, i'm not really sure where it is on my car. I've never had to do anything with the a/c system before. Also, if i replace the compressor, is the clutch part of that, or is that something separate that i also have to replace?

Thanks guys.

Post by **jimmy57** » 13 Apr 2011, 10:58

How will you know you aren't getting a compressor with more miles on it from a pick n pull on a car with an electronic display odometer?
You realize the system will need to be evacuated for at least 30 minutes and charged by weight.
Compressors can last 200K + miles.
Removing a shim from compressor shaft driven pulley is not too hard and cures the problem for tens of thousands of miles.