my new to me 02 is taking a couple of minutes to get cool. I was thinking of adding a can of freon, the PO said it had never had any added. Good idea?

 

Absolutely NOT. These systems are very sensitive to the refrigerant charge. As little as 2 ounces over or under charged will cause performance issues. Overcharging can and will cause over pressurization and can destroy components in the system, (compressor, condenser, accumulator, evaporator, and lines). The only way to know how much refrigerant is in the system, is to drain, evacuate, & recharge it with the proper amount of Suva, (not Freon), commonly referred to as R134a. Servicing these systems requires a manifold gauge set, an evacuator, and at least a basic knowledge of air conditioning. The cans available to add refrigerant, if used improperly, can explode like a grenade in your hand. Most auto parts stores rent/loan manifold gauge sets and evacuators. When you have them available, we can help you.

 

Is that concern just for the 02 Blazer or is it applicable to automobile AC systems in general?

 

Holds true for all HVAC systems: automotive, residential, and commercial. Types of refrigerant vary, and the metering system varies though. Automotive metering systems are unique using a cycling clutch and a fixed orifice tube, which makes diagnosis procedures unique as well.

 

Suva is a brand name. http://www2.dupont.com/Products/en_RU/Suva_en.html
Make sure you use 134a when needed.

 

Correct, Freon is the trade name for (CFC) R12, and Suva is the trade name for (HFC) R134a. They are two different chemicals, and are not compatible with each other in the same system, at the same time.

 

https://www.chemours.com/Refrigerant...products/Suva/


Suva is "Dupont's" name for refrigerants not just 134a.

 

My manual came yesterday. It explains how to check for low refrigerant by checking the temperature and how to add refrigerant using a can.


Captain Hook, I don't understand your comments, "Absolutely NOT...destroy components...explode like a grenade." It seems to me the AC system is pretty much just like every other car. What am I missing?

 

The only way to know how much refrigerant is in the system, is to drain, evacuate, & recharge it with the proper amount.


Too much oil, or refrigerant, can cause over pressurization which can cause lines to blow apart, destroy the compressor, accumulator, evaporator or condenser. The weak link WILL fail, violently, very rapidly!


If the can is exposed to high side pressure, or low side pressure is too high, the can WILL explode. Look on the bottom of the can, there is a semi-circle breakaway. If it works, fine, if not, it can be lethal.

Several statements in that image are downright incorrect, which is typical for Chilton/Haynes. Don't trust it. Best to return it and get your money back ASAP. If you want a shop manual, get a genuine GM "dealer issue" manual for your year and model. Ebay usually has used ones at reasonable prices. Your Chilton/Haynes manual covers multiple years in under 200 pages. It includes incorrect and or missing information, incorrect specs, and incorrect procedures. It is "general information" not to be taken for gospel, by any means. GM shop manuals cover one year, in two or three volumes, with over 3000 pages. Sure it costs more, but you're getting correct, accurate, complete information, procedures, and specs.

 

Puttster,
Here is the post when I had to redo my A/C. Follow Captain Hook's advice and you will have COLD air. I was fortunate as my compressor had not gone bad, just a small leak our of it and some connections on the line. If the compressor has gone bad, it throw tine pieces of metal throughout the A/C system and it needs flushed and most likely at least a new condenser. At the least you need a new accumulator and orifice. Here's link to the post.

https://blazerforum.com/forum/2nd-ge...pressor-90114/