A/C gauge and pressure question for '97 Blazer

My S-10 Blazer has been having A/C problems. It is a 4.3L engine. I bought some gauges this weekend (seems like I always need some so I bit the bullet).

Pressures are psi. Refrig: 134a, factory installed. Static Pressure: H85, L87 Running Pressures: H 130, L 126 Both gauges show 102F for temparature Outside temp is about 98F Blows warm to hot air. This was somewhat gradual, i.e., it didn't blow cold one moment then hot the next.

The sight-glass in the manifold shows liquid about half-way up the glass with some bubbles on top.

The instructions with the gauges say to open the low-side while the system is running. However, it reading through some service books at the library, they say NOT to open the low-side while the system is running. If I keep the low-side closed, the pressure is around 75-80psi.

So, two questions:

1) Am I supposed to keep the low-side closed while the system is running? 2) What are my pressures supposed to be? (I realize this is ambient pressure sensitive, figure 100F 'cause that what it's likely to be around here for at least the next week or so)

Thanks in advance

Bill W

Reply to
Bill Weissborn
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If your low side is 75 to 80 lbs running, you either have and overcharge or a retriction in your system.

Your compressor may or may not have a problem also.

What work has been done if any to your A/C system?

Pressures should be under 40 PSI on the low side. 75 or 80 is much too high.

Reply to
Hardpan

In addition to my other post some more questions:

You can open the low side running or not. Make sure you purge the air out with some R134a.

No.

Depends on the model and the ambient temp.

Manual says 26 Low and 299 High. PSI

Volume 2.00 lbs R134a

These can vary of course.

Are you getting any cold lines in the engine compartment or are they all hot?

Is your clutch working? If so, does it cycle?

Reply to
Hardpan

A rule of thumb for hi side pressure is 2.2 to 2.5 times the ambient air temp.

Reply to
48areo

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