The Delco sticker on top of the evaporator housing says 1 lb 12 oz(or 28 oz), but the owners manual says 30 oz or 2 lbs. I have searched the net and get conflicting numbers. Some say 30 oz and some say 32 oz, but nobody says 28 oz except the sticker under my hood. I know the 99 blazers are supposted to take 28 oz( I've done too much research ), but I know I have a 1998 model. The vin number tells me it's a 98 and the sticker on top of my radiator says 1998 model. I also replaced the compressor as part of this A/C overhaul and it matched up with the 96 - 98 models. The 99 and up compressors had a different pulley. So I know I have 1998 model parts. I evacuated my ac system and want to put the exact amount of freon in so the system runs as well as it can. Can anyone tell me what number I should trust? Thanks in advance!!

- Matt

 

My reference shows 32oz. It also shows a high/low side pressure of 299psi/26psi with an ambient temperature of 80F, relative humidity of 60% & engine at 1500RPM.

1.75lbs (28oz) is what I show for the 99+. But I also show that the 98's could have had the HT6 (which is shared with the 99+) or the HP6 compressor. Really, everything should be the same as the 99+...

My recommendation, go to 28oz and see what your outlet temps are. If they aren't to your liking and your high/low side pressures aren't too far off, then add a bit more in. 4oz shouldn't cause the system to go boom.

 

Man, you are awesome! Thanks for all the great information! So it really depends on which compressor you have? Does it have anything to do with having computer climate control or manual controls? Is the sticker on the evaporator housing worthless? Thanks, I very much value your opinion. This is a great forum!!

 

It does not matter whether it is manual climate controls or automatic.

 

The thing that's getting me is that the sticker under the hood says 28 oz and the book says 30 oz or 2lbs(32 oz). I just ened up puting 30 oz in. Right in the middle of what the book says and the label on the evaporator. 28 oz didn't seem cold enough. 30 is pretty much putting out icicles. And I figure I can't go wrong being smack dab in the middle. July is the wrong month NOT to have air conditioning!!!

 

Glad you got it workin'!

 

I have always been told to trust the sticker under the hood instead of the owners manuals. When gm has millions of books printed im sure they wont destroy millions of books if there is a design change midline of a production run. I seem to remember reading in an owners manual somewhere that you should reference the underhood sticker to verify the book on certian items.

Glad its working right for you though.