Chevy Malibu A/C - charged, no cold air

davescountry · 05-08-2011, 11:59 AM

All - thanks in advance for the help.

I have a 2000 Malibu and can't seem to find much on this problem. Basically the AC doesn't blow cold.

I picked up a new gauge today from O'reillys. When I attach the gauge and fire everything up, it gives me a reading of about 50 psi. I turn on the AC and the compressor seems to be cycling, but nothing cold is blowing out of the dash. Its about 84 degrees here today.

I had the problem last year where the AC switch on the dash wouldn't stay on, which seems to be a big problem. So, I took apart that switch and cleaned everything and put it back together. The AC will stay on now, but the recirc is a little intermittent.

Any ideas on what to tackle next? I don't have much experience with AC units, and no real access to the higher end tools.

**octaneman** · 05-08-2011, 12:41 PM

Hi davescountry

There are two possibilities either the freon level is low and needs to be recharged or the condenser is not doing its job. The system has to be completely evacuated and then recharged in order for the A/C to work properly, if the system has air pockets it will prevent freon circulation. Road conditions also clog up condensers over time, dirt and crud get jammed into the air passages preventing the freon gas from changing its state.

**Midnight Tech** · 05-08-2011, 07:04 PM

What is the static pressure in the system (when the car's not running)?

luvvgunn · 05-08-2011, 07:27 PM

Yea all the stuff those guys said, and I'll add stuck gate in the vent system.

davescountry · 05-08-2011, 09:51 PM

Quote:

Originally Posted by Midnight Tech

What is the static pressure in the system (when the car's not running)?

I will check that early in the morning and report back.

**kjms1** · 05-09-2011, 07:35 AM

you told us it was 50 psi not running but you didnt tell us what it read when you turned it on ... plus we really need to know what both pressures (High & Low) are to give you a more educated guess to the problem ... both High & low need the correct readings for it to work properly

you say its charged up ?????? are you sure ... 50psi not running sounds low
does it cycling on and off pretty fast when you turn it on
If yes
low on freon OR orfice stopped up ... what are both sides reading
OR
condenser stopped up OR fans not cooling system ... whats the high side reading
OR
low or high pressure switch stuck or not working ... what are both sides reading
OR
compressor free wheeling ... whats the low side reading

davescountry · 05-09-2011, 08:23 AM

OK, I might be getting ready to get a bonehead of the year award or something.

Yesterday, when I put the gauge on, it read right at 50 psi, with AC running and not running both. This gauge is not the best. Its basically a $25 interdynamics gauge I got at O Reillys. I did notice that the gauge does not zero when unattached.

Today, I went out and put the gauge back on. Now, with the AC not running, the gauge reads right at 60PSI. I turn the AC on, and the pressure drops down to 30PSI, very different from yesterday.

I went ahead and opened up the can of 134 and the pressure did rise to almost 40PSI, then dropped a hair to about 38PSI. I think the can then emptied. Its fairly cool here this morning, but I think the air started blowing cold. I will look around to see if I have a thermometer that can read low enough and stick in the vents. I may also get another can and test later to make sure pressure is holding and take it up another 10PSI or so.

So, I don't know what happened yesterday. Sounds like I could have been making some errors, or perhaps something was clogged and just worked through with a little pressure on it. Again, I will check it again later today and see if anything is substantially different.

Thanks for the inputs. I have a Chevy Tahoe I will be tackling next, so might see another post from me - assuming this problem is fixed.

**Midnight Tech** · 05-09-2011, 08:54 AM

I'd go pick up a standard manifold set that hooks to both low and high sides - it will tell you more about the charge condition than that little gauge. NAPA has a good one (BK 765-6009) that's made by Quest.
Knowing both low and high side pressures will help a lot in diagnosing your system.

davescountry · 05-10-2011, 09:18 AM

Thought I'd post back on this. I don't know what I was doing that first night, but the problem seems to have resolved itself.

Yesterday, after putting in about 6oz of 134, the pressure with AC on went to about 38psi, with AC off, about 65 psi. The air was blowing cold, and using a meat thermometer (only thing I had) leveled off around 60 degrees on the vent pretty much right from the start. I took for a test drive, and the temp dropped to about 48 degrees on the vent. Since my pressure was at 35, I may try and put in a few more ozs and see if I can get that vent dash down a few more degrees.

So, sounds like something just wasn't kicking in the first night, or I wasn't paying attention. I do have a Tahoe that I am troubleshooting as well, so might see you guys in a new thread I am going to start. Thanks for helping out through my boneheadedness.