Yet another AC Question

Hope this is the right Section....

On my new to me 02, The ac works great and blows COLD when you are moving at decent speeds. When you slow down, stop, or are riding slowly through town it gets almost warm. But when you get moving again it goes right back to cold..

Any ideas?? Thanks.

My wife's '05 Fivehundred does this also. I checked the charge and it is to the correct pressure, I am starting to think it is the A/C clutch.

A little side note, it doesn't seem to do it as bad if it is on max ac...

Sub'd.

You got yourself a lemonoke:

check ur gap on the clutch on the front of the compressor. if its to large it will only engage if the rpms are high enough. mine did the same thing pulled the clutched of took out the little spacers an bam good as new

Isn't there a good write up somewhere on messing with the clutch?

:whs: I would really like to do this!

Also check for a vacuum line or vacuum motor problem. All of your airflow mode doors are moved by vacuum sometimes with the exception of the blend door.

what does it do if you run around with it in 2nd gear so the RPMS are higher around town. if its RPM dependent i would bet that its the clutch in the compressor or the compressor is just getting weak.

Like I said, for the most part it blows cold. I noticed it the worse the other day we had been on the highway for about 40 miles, got off and while sitting at the light it got almost warm.

It's most likely the clutch... We've got that...

Now does anyone have a how-to?

Mines doing the same thing, it used to frost the bottom of the windshield but lately its been doing exactly what your describing, any info would be great!

99F250Smitty said:

Hope this is the right Section....

On my new to me 02, The ac works great and blows COLD when you are moving at decent speeds. When you slow down, stop, or are riding slowly through town it gets almost warm. But when you get moving again it goes right back to cold..

Any ideas?? Thanks.

Click to expand...

yeah, a couple..
being as it appears to be airflow related, I'd be checking three things..
1. Charge level. How is the clutch cycling time? 20 seconds or so "on" time?
2. Could be moisture contaminated. This most commonly happens when they get low, and someone charges it with Wal-Mart hand grenades. Needs to be put in deep vacuum for at least 45 minutes (or change the accumulator and vacuum it for at least 15 minutes).
3. Fan clutch. If it's not engaging properly and drawing air across the stack, you'll get poor cooling..

If I knew what the pressures were at idle, and at 1700 or so rpm, I could give you a better idea.

If the compressor dwell time is like 20 seconds, and hosing the condenser down with a garden hose on mist cools it right off, you're looking at either solution #2 or #3.

In the mean time, I'd backflush the stack with a hose, and make sure there's no crud, mice, dirt, trash, etc. impeding flow through the stack..

Forgive my Ignorance, but what is the "stack"?

Im going to lean towards #3. I just fixed 2 friends Ex that were doing this with them. At idle both had increased high side pressure to the point of hitting the high side cutoff and shutting down the compressor. 1 truck even came close to overheating sitting idleing for 30 mins. Coolant and trans temps both reached 230*. Also both trucks were seeing increased trans temp for the last year. Both have dropped the trans temp 20-40* in stop and go traffic in the 90*+ air with a new clutch.
The best deal for one is through Rock Auto. They have Motorcraft ones for $175
As far as "the Stack" they are refering to the radiator, intercooler, condensor and trans cooler.

Makes sense. Is there a way to tell if it is engaging properly or not? My Trans and coolant temps seem fine.

http://www.rockauto.com/catalog/moreinfo.php?pk=379586 That the part?

99F250Smitty said:

Makes sense. Is there a way to tell if it is engaging properly or not? My Trans and coolant temps seem fine.

http://www.rockauto.com/catalog/moreinfo.php?pk=379586 That the part?

Click to expand...

yep!

JLDickmon said:

yep!

Click to expand...

Okay, but like I said, is there a way to check that before I just throw a part at it?

if it's locked up tighter n' a drum, it's junk.
if it freewheels a pinwheel in a hurricane, it's junk.

anything in between, most likely good.