A/C blowing hot, clutch is engaged, plenty of pressure - blocked orifice?

[Qshiplvr]

Today, the car was sitting idling, and all of a sudden, blew hot. It was about 89 degrees outside, not terribly hot (at least on a desert scale). Setting EATC to Max A/C didn't help.

Took the car home, popped the hood, hmm...clutch is engaging, there is sweat condensation on the high side tube, and very cold to the touch.

I hooked up an ACpro 134a can w/ pressure gauge, and it was at the top of the yellow range, almost into red, so definitely NOT low on freon (R134a).

The A/C system was serviced, freon refilled topped up about 1.5 yrs ago (1400 miles since then), so I know the components are pretty fresh.

Any ideas on next steps?

Oh, and the last service tech made a note...one of the bolts on the a/c compressor was cross threaded. GREAT.

 

[Texas Marauder]

Took the car home, popped the hood, hmm...clutch is engaging, there is sweat condensation on the high side tube, and very cold to the touch.

Low side should be cold. High side should be hot.

You need a set of real gauges to see what going on.

Years ago, on my 97, I had a strange A/C problem. I don't remember the exact symptoms but, seems that it would cool somewhat at speed, not at idle. The cause was that the tube (the actual orifice) inside the orifice tube moved back so that it restricted the flow of refrigerant. The orifice tube is oriented horizontally front to rear. I theorize that a sharp jolt while the system was working allowed the tube to slip.

 

[E1]

OOH, OOH - I got this one !

Remember HOW many times I told that nice fellow from Texas, Hollon71, to do a 'Shim-ectomy"?

When the engine is relatively cool, the AC works well. After the engine and all of its components heat up to full operating temperatures, all of the sudden the AC quits working.

The clutch clearances might be at the break point. When the clutch heats up and expands that little extra bit, the clutch will disengage normally for whatever reason, but will then no longer be able to re-engage properly (It MAY engage partially, but be slipping) until the engine fully cools down again.

Let the car cool down fully. Restart the car and turn on the AC full blast while the engine is still cool. If it does not work, look to the orifice tube as mentioned.

If it works - Open your clutch. Remove that tiny little spacer. Reassemble. Enjoy the cool.

 

[gamefanatic]

Sounds like from what you are saying the A/C is functioning. If you aren't feeling any improvements even when the engine is above 1500 rpms, maybe your blend door motor is not functioning? This would certainly prevent the air from becoming cold. Can you make it go hotter?

 

[Tbird6]

Great point about the shims and the clutch clearance BUT it was my experience that when the wear reaches the point of changing shims your better off replacing the compressor. The repair did work but a few months later the compressor gave up and had to be replaced.

You don't randomly put shims in? There is a specified clearance in the shop manual and the gap needs to be set to that range. Ford had a number of different shim thicknesses to obtain the correct clearance. I don't know at this late date if they still sell them?
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