Main IndexAuto Repair Home Search Posts SEARCH
POSTS
Who's Online WHO'S
ONLINE
Log in LOG
IN






Search Auto Parts

97 Yukon A/C wont work well above 90F


  Email This Post



muvovr
New User

Sep 19, 2007, 4:21 PM

Post #1 of 2 (1597 views)
97 Yukon A/C wont work well above 90F Sign In

I live in Phoenix Arizona, so extreme heat!! My 97 yukon 4dr 5.7L Vortec, has an several issues involving the HVAC system. 1. The front air output is weak, ive had the door valves replaced for air direction, and a shop cleaned the heat cold valve and said it was fine and that nothing was blocking the system. Also had a new blower motor installed but nothing. 2. the AC temperature at outside temps above 88F will blow somewhat cold air but that only if you put your hand right up to the vent, temperature is equal between front and rear systems. System was evacuated and recharged 1 month ago. Any outside temp. below 88F the AC is incredibly cold, to the point you must turn it down or freeze.

*also when driving at highway speeds 75-85mph there is some surging, tried to just off the HVAC system but hard to tell if it goes away, i dont believe it to be drivetrain related though. It feels like the AC cluth is gogin on and off, but it is not consistant.


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Sep 20, 2007, 4:45 AM

Post #2 of 2 (1586 views)
Re: 97 Yukon A/C wont work well above 90F Sign In

I think the charge is wrong. This is a complicated dual system with one condenser and one compressor with two separate evaporators - one uses just the O tube and the rear uses an expansion valve. Having the exact #of oz of refrigerant is critical. There's a problem with this vehicle in the data of the exact amount it should have. I just looked at two charts and one says it should be 57oz and another says 64oz. The vehicle should have a decal on the accumulator/drier stating what this exact one should hold.

Go look at that decal - yellow with black print and see if it's there. If that part has been replaced since new and the wrong decal was put back it's going to be difficult. 134a refrigerant is fussy about being very close to the exact amount for best performance at various ambient temps. Can you find out if the sticker is original and how much was put in when it was recharged? It could have the problems you describe with an improper charge and might not be noticed until used in that extreme heat,

T







  Email This Post
 
 


Feed Button




Search for (options) Privacy Sitemap