eaglepassbird

Hi everyoneim having ac troubles in my 97 tahoe I know is not ls1 related but maybe yall can point me in the right direction
Everything has been replaced ac compressor ,lines , evaporator ect but it still blows warm air my manifold gages shows pressure of 40 and 250 on a side note my ac has to be activated via a toggle switch to kick on the clutch
When my inside fan is off my gages go to the right pressures 28 and 290 and if ui turna the fan the ac will blow icy cold then get warm again
Anyone got any ideas or can point me out in the right direction

Thanks

eaglepassbird

Sorry about the clutter typing from my phone

DAVE00

iTrader: (10)

Make sure your actuator/temp selector door is isolating the cold air only and not pulling from the heater core.

00pooterSS

iTrader: (40)

Pressures sound pretty good so it should cool. Those body style Tahoe's are notorious for having poor performing a/c but it still should be cool.

In these temps it would also be acceptable to see around 300 psi on the high side at idle if you are outside in the ambient temp (100+ degrees). It going up to 40 on the low side when you turn on the fan is normal because you are now introducing more heat to the low side via running hot air over the evap coil and the freon expands. Try a little more freon and see if that helps.

Did you put a really good vacuum on the system before you charged it with freon?

eaglepassbird

Pulled a vacuum for about an hour and it held it for a good hour after I turned it of f I'm thinking of bypassing the heater core

00pooterSS

iTrader: (40)

Bypassing the heater core helps if the blend door isn't closing all the way, but if it isn't then you still wont get as much cooling as you should, which you may know.

Rev it up and see if it cools better, if its a rebuilt compressor it may be a little weak and not moving enough freon.

But, again.. I would add a bit more freon. Its easy to release a little if it goes over charged.


Also, have you put a temp probe in the a/c outlet? On those Tahoes it wasn't surprising to only get about 50 degrees out of them. Lower 40's is about the best you will get in most vehicles... and that's in the shade, fan on low, interior already cooled down, and on recirculate. There are some cars that are exceptions and will get in the 30's. I was never satisfied with the a/c performance in those model Tahoe's I replaced several compressors and did full flushes, exp valves, orfice tubes, accumulators, the whole deal and they still sucked. A friend I worked with for many years worked for GM and told me that around the dealership all the guys hated those Tahoe's as well because of the poor a/c performance.

eaglepassbird

I bypassed my heater core today put my gages on and now the low pressurrs are 85 and high side is 300

This truck is driving me crazy im thinking the evaporator I bought migjt be clogged or the condenser but they are both new