stratocaster64

I own a 98 Blazer that blows very cold air for about 20 minutes or so, then it is as if I turned it to vent and then starts to warm up. When I first discovered this, I though the air went out. But every day I start it up it is cold again for awhile.
Is the air freezing up and shutting off? Or could there be a loose connection and shutting off.............Anybody??

gmtech79

Please watch your clutch for awhile and post back if it cycles off and on or if it constantly stays on. It should cycle off and on to prevent evaporator freeze up.

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MT-2500

Welcome on your first post on AF.
First thing would be to check for low freon.
To properly and safley do this you will need a set of air cond recharge gauges with high and low gauge.
Not one of them Wal mart recharge death kits,
Post back low and high pressure readings at idle and at 1500 RPM.
http://www.ackits.com/merchant2/merc...uct_Code=66773
http://www.ackits.com/merchant2/merc...e=DIY-STARTER1

And if it is low. Read this.
#1 Freon is non consumable, if it's not there then there is a leak
#2 A/C is a delicate balance between liquid/gas (low side/high side) and too much freon is just as bad as not enough
#3 If you are not prepaired to buy a set of A/C gauges, and be willing to possibly buy a vaccum pump or a/c die and replace the proper componets, then don't even waste your time.
#4 90% of the time your going to have to pull a vaccum, flush the lines and most the time replace the accumilator and the Oriface tube/expansion valve.
#5 The only easy fix is if one of the pressure switches is bad, there is no just add freon fixes.
#6 Please Please don't just add freon w/ a charging kit because you think it needs it, It doesn't work like that.
#7 These guys are a execlent source for help and if you listen to the procedures as you are told you will end up w/ some ice cold A/C, being hard headed is expensive.

http://www.autoacforum.com/
#8 And here is a link from AC kits.com to what a person needs to recharge a air conditioning.
A/C starter Kit
#9 Adding freon to a system that has a good charge can be dangerous and can cause you harm, if the pressures get to high and blow the freon can or something in the system.

MT

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Remember proper testing gives us the answer to many problems.
MT

stratocaster64

In reply to gmtech97:
I ran the air for about 30 minutes with the hood up, the air was cold, but it didn't appear that the clutch was turning off and on. The evaporator tank stayed wet and didn't frost over.

MT-2500

I am not gmtech97 but
You have a problem there. Something is not quite right.
Get the gauges on it and post back the low and high side pressure readings at idle and at 2000 RPM
MT

__________________
Remember proper testing gives us the answer to many problems.
MT