2004 Hoe LT AC problems.......

[Fatmikeslim]

help me please im freaking lost.......



Bought an 04 Tahoe to make a road trip vehicle (third row big crew).......
And the ac didn't blow frosty air ' just cool....... The person i got it from told me it has a new ac control head (still has plastic stickers on it) and was unsure what to do next........ so i bought it cheap with the intentions of fixing the problem and having a nice people hauler...... first thing i did was check the pressures it was 95f outside and the low side pressure was 90psi and the high side was 300psi.........whoa i know.....
So after a couple mins of thinking i washed the condensor out (that wasn't bad) the head pressure dropped some. But soon returned to close to 300psi. So i figured it was way over charged' i pulled a good vacuum on the system ' let it sit 2hours and recharged it with 44 oz of 134a (it has rear air)....... exact same pressures......... then thought ok high head high low air flow prob so i swapped out the fan clutch..... now we're like 280 psi head but still 64f degree air in center vent. After talking to a friend he convinced me to swap the compressor ' orifice 'and drier' and expansion valve ' what a chore...... vacuumed again 30mmhg' held for 2 hours ' and recharged 44oz of 134a.......now the low side is 65psi and the high side is 275 dash air 62f.....rear air 62f. ........ if i vent some 134a the dash air instsntly gets warmer and if i am scared to add more because of the high pressures.......... i also washed out both evaps really good and have good airflow ............ i don't think its blend doors the operate awesome ' and the pressures show the same temps as the freon does...... The cold side of the evap up front is sweating bullets and COLD ' the out let of the evap is cool ish ...............i feel like its first and goal ' and im punting .........i honestly am lost now and want cold air

 

[rockola1971]

Did you open the rear air up any? And you replaced the expansion valve at the front? Typical problem on these is the rear expansion valve is the first to get plugged. Does your compressor look fairly new? I suspect some replaced one that threw its guts up but didnt flush the lines and replace plugged up expansion valves, driers, orifice.

 

[Fatmikeslim]

Orifice and expansion valve impeccably clean ' and replaced ' new compressor never seen any debris new drier no debris....... and i looked for some

 

[rockola1971]

Did you open the rear A/C up? Check there? Its very common for the rear to have problems. Expansion valve gets clogged up and we wont even get into the controls portion of the rear and all its typical failure problems.

 

[Fatmikeslim]

Ive yet to see debris of any kind ' new expansion valve warm on upstream side cool on down steam side rear evap and front evap both blow 62f air......at best

 

[rockola1971]

With evaporators cool not cold, discharge air being 62, pressures are way too high both sides... Blockage or kinked line(s).
Take thermal reading of condenser inlet and outlet and see if there is a substantial temp drop on the outlet side. If there isnt then your condenser is blocked. Is your low side even cold?