Uggghh Another A/C Question

Hi All,

I know there have been a thousand questions in regards to A/C and in the last few weeks I think I have read all of them but have not found on that is quite like this.

So A/C in my 2003 Z71 used to work fantastic (like meat locker cold) in the last couple of years especially last and defiantly this year has been cooling less and less till now nothing but warm air.

This year we got our first hit of 75 to 80 degree F ( 22 - 30 Degree C for us Canadians) weather and now I have no A/C blower works no issues there.

What's been checked:

Compressor working = Yes Cycle's correctly and can hear the fluid moving through the line
Low pressure side with ac off @ about 80 degrees F 30 degrees C 70 LBS
Low Pressure Side with A/C Cycling drops to about 15 LBS before Compressor Cycles off

Blend Actuators both (duel Climate Control) are working correctly.


But still no Cold Air 

I am at a loss on where to go from here any suggestions or input would be appreciated.

Melting Mudboy68 

Are you saying no cold air at all when you first turn on or is clod and then goes warm? If has cold first then suspect freezing up problem of system. If no cold air at all, even when first turn on, then suspect blend door problems. Have you recently unhooked your battery?

Nope warm from the get go took whole dash apart today blend doors working fine and so are the actuators.

Thanks for the reply though

Mud

Sounds like you have a slow leak. Might not be enough freeon in the system.

Well low side gauge says different with engine off at 80 degrees is a needle width below 60 lbs so should be full.

Cheers

Mud

High side readings please. Should be close to same when a/c is not on. Does sound like low system since has no cool/cold at start but would like high side readings. The normal static pressure at both sides, depending on outside ambient temp, is 80-105 psi. With a/c on max and high fan the low side should pull down to 25-35 psi before cycling and the high side can climb to 200-300 psi, again all depending on outside ambient temp and humidity. Once those pressures are reached you can measure temp at middle vent and get anywhere between 42-55 degrees, depending on ambient temp and humidity. Do not overcharge because can damage the compressor and performance will suffer and temps will climb. Even if compressor is ok and overcharge the temp will climb. The only way to guarantee a complete full charge is to recover with machine and then put in the exact amount on the sticker under the hood. Lower fan speeds can produce cooler temps because of less fan turbulence. Use max fan when first turn on and then as the temp lowers in vehicle the lower fan speed is good to maintain. Confused yet?  


I lived in K.C. for 35 years so did lots of a/c work.

Unfortunately I will have to see if I can borrow a set of manafold gauges to read the high side just was using one that came with a recharge kit for the low side.

Thanks for the advice might just have to pony the dough and get an AC shop to drain and vac and refill for me.

Thanks to all who replied you guys are awesome as usual.


Cheers

Mud

If you want you can add on the low side and watch for the low side pressures I gave you and then see if it cools like it should. At that point you will know the system is low with a leak. Bear in mind that when an a/c system is low, because of leak, as the refrigerant gets lower then the static low pressure is lower and the leak will be slower. Some people don't think that they have a leak because it is not completely empty. It would eventually be completely but the bigger the leak the fast it leaks. Should draw down the system and then have diagnosed for the leak and fix it and then recharge. depending on the source there is a few things that should be done when system is open to repair the leak. We can go over that if needed.

It sounds like you have the intermittent Low Pressure Cycling Switch problem: TSB 03D-J-128.

http://www.acdelcotechconnect.com/pdf/tsb/tsb_03D-128.pdf

Blacklane said:

It sounds like you have the intermittent Low Pressure Cycling Switch problem: TSB 03D-J-128.

http://www.acdelcotechconnect.com/pdf/tsb/tsb_03D-128.pdf

Click to expand...

Or that! LOL!