AC cooling for 98 5.7 vortec ext cab
 

I have cool air coming from the vent in cab, compressor is engaged fully when on. I have vac'd the system down and refilled with 3 cans of r134, the low side of system is reading 25-27psi.. the air is semi cool and not cold, should I put in another can of r134 or try somthing else? And prior to this the air was ice cold, I had to replace the scraider valve on the low side...

is the system at full capacity? did your truck use r134 or r12

the system is R134, and that is what I put in. Is it full?, that is why I posted the question, I put in 3 cans of r134 and still not cooling, but the low side pressure is 25psi, which is the lowest acceptable reading. So do I put in another can to bring the pressure up a bit more or stop and restart somewhere else...

it should say i believe on your hood or somewhere in the engine compartment how many pounds of freon that need to go into the system.

It states 2 pounds of r134 that is why i stopped at 3 cans.....dont know if I should add another can or try something else

How much was in each can? Did you get the can completely empty? How did you vac the system and for how long? Are you using a real set of gauges or just something attached to the can? If so what is the high side reading? The pressure does seem low but other info is needed to be sure. Is the compressor cycling on and off ?The 25 is that the reading right before the compressor cycles? What was the outside temp at the time of the reading? What is the high side reading right before the compressor cycles? Did you add any oil to the system after vacuum?

total in each can is 11oz each.....can was completely empty....vac it down for appx 45 minutes and had 27" of vacuum...gage was attached to the can at that time. hign side I did not read did not have gages for that...the compressor was NOT cycling after one and half can of r134.... 25 is the reading at the gage with compressor engaged and not cycling, the compressor is not cycling at this time locked in continuely...outside temp was 71 degrees...No oil added.

I hope this is a little bit of help....thanks

The truck calls for 2 pounds. 160z in a lbs. 32oz total. You need to add another can for sure. It will only be one ounce extra but using that style of charge it is not likely that 100% of every 11oz can made it into the truck.

ok thank you i will give it a shot this weekend.... that is my goal. going to replace the axle seals first then i jump on the ac....again thank you for all ur helpl, i will let u know how is goes...

Ok,,, this what i got going so far with the a/c... I added the one more can of 134...it is a bit cooler now,, but the compressor cycles only when the rpm's are up, ie.. reving engine... when idleing.. the compressor stays fully engaged. Is this normal??? could it be still low on r134? the low side pressure when ac is on is 25-27 psi.. when compressor is off, it is appx 45psi..low side. I have noticed the suction side line now is much colder than before.... any tips??... add some more or try something else....???