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Comp. cycling, no cool

Mine2go on Wed August 03, 2011 7:47 PM User is offlineView users profile

Year: 2000
Make: Mercury
Model: Mountaineer
Engine Size: 5.0
Refrigerant Type: R-134
Ambient Temp: 90's
Pressure Low: 36
Pressure High: 125
Country of Origin: United States

Hey guy here trying to learn what I can. A/C's always been a mystery, now it's getting a little clearer bit by bit. Here's the scoop: 2000 Mercury Mountaineer 5.0 V8, auto climate control, a/c has worked great til now.

1. Holds static pressure of 72 hi/60 low for days
2. Go to MaxAC...comp. clutch kicks in for 2 sec., quickly goes to 125 hi/36 low
3. Clutch kicks out for 5 sec., slowly goes to 90 hi/46 low
4. Repeats cycle
5. Haven't jumpered low pressure switch yet (don't wanna damage comp. if it's still ok)
6. Haven't added R-134 yet but pressures seem low
7. Curious about what's causing the comp. clutch to kick back out after 2 sec., with pressures moving in the right direction

Added 11 oz. R-134, 1oz oil (with leakstop) end of last summer, cooling went back to normal. This summer was fine until 4 weeks ago, cooling dropped off then quit altogether. It's been hot (hi 90's-100's with tons of humidity). Probably a slow leak for sure, but the sudden loss of all cooling has me puzzled. If I had a major leak static pressure wouldn't hold at all, right? Clogged orifice tube maybe? Any ideas where to go from here? (besides the stealer )

JJM on Wed August 03, 2011 10:16 PM User is offline

Sealer probably did its job, now you're stuck with the bill. Probably a total system replacement at this point, though the pressures appear as if the system might have a little more life left. Just don't expect miracles.

Since the system is probably toast by now, can't hurt to add more R-134a and some oil (PAG 46), but stay away from the leakstop, sealers, conditioners, and boosters.

Leak was probably at one of the peanut fittings, since I think Ford did away with spring locks in most vehicles beginning in 2000. An improvement, yes, but not by much.


When considering your next auto A/C purchase, please consider the site that supports you:

iceman2555 on Thu August 04, 2011 4:50 PM User is offlineView users profile

The darn thing probably does not have sufficient refrigerant to operate. The sealer probably does not help....but there is not enough refrigerant to operate.
Static pressures do not reference the amount of refrigerant in the system...only the presence of refrigerant.....1 oz....10 oz....100 oz...all the same......

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