A/C not blowing cold

[dstig1]

First off, I've done a bunch of searching on the forum and there is so much to plow through that while I have learned a lot about AC, I have not seen my issue (though I am sure it is out there somewhere). I have not dealt with AC much in my life, though I do all my own maintenance on all our cars (from simple to really major).

'99 Explorer AWD V8, R134a (original)

Here's the readings at 1500 rpm, after stabilizing:
Ambient: 80-81F, Center vent temp - 72-73F (that's what the themometer said, but I don't think I was getting it in there well enough - air was cool but not cold like it should be)
Hi side 100psi (below limit)
Lo side 97-105 psi (above limit)
On time - 8 sec (Below limit)
Off time - 6 sec (OK)
Total cycle time - 13-14 sec (Below limit)
#cycles/min - 5 (above limit)

If I believe the Helms manual diagnostic tree, it says "check orifice tube - if present, compressor is weak - replace compressor." Well, the system has never been opened (original owner), and it was starting to get weak last year but fine before that so the orifice tube is "present".

Even though it doesn't say it in the manual, is this possibly a low R134a issue? Or is it time to replace compressor (and accumulator, natch)? I can get the Vacuum Pump From Hell on the lend-lease program from work, so I might even be able to do the whole thing myself.

Thanks for any help.

 

[Glacier991]

That fairly screams at me that the compressor had bitten the dust. I love that you can provide such important info to make a diagnosis. THANK YOU!!!!!!

The reason they ask if the orifice tube is present is that those pressures either say the comprssor is shot, or there is nothing to pull against for the compressor (orifice restriction). Since you know the orifice tube is present, the end result is inescapable. BAD compressor.

 

[dstig1]

Bummer. Well, thanks for the info. I guess I should trust the Helms manual more, but I was hoping for a easier/cheaper way out (of course).

So does this mean that the compressor has trashed the system (like I think I read in one of your other posts)? I read through the threads on DIY AC work, so I know what needs to be done for replacing parts and re-charging the system but are the internals going to be gunked up everywhere due to this and require more than just replacing the comp and accumulator? Probably should do the orifice tube at the same time, right?

Another question - The reason I was tearing into this now was that we are going on a trip soon (1000 mi each way) and I wanted decent AC for it. So far, it still works, but is weak. Now I am concerned that perhaps the comp might seize up or grenade. Any real risk of this or is it just "wearing out"? This is going to be a big job and I don't think I will have time to get this done before the trip, so it would have to wait until after, but I don't want it to grenade on the road. Weak AC I can live with - Seized compressor I cannot...

Thanks again for the help. It is immensely valuable to have experienced folks like yourself answer questions like this.

-Dave