how cold should the rear AC be?

[T3rry]

I just changed my compressor as the clutch had failed, had the shop vacuum and recharge the system, and picked the truck up..


how cold is the rear AC supposed to be? i have the front AC on and i can feel it pretty cold, however, the rear doesn't seem to put out much "cold" at all, it seems to be the same temperature as if it were just set to "cold" without the AC on... does the front have to be set a certain way for the rear AC to work? i had the fronts on, with AC enabled, and the rear set to cold, and auto fan (which was basically full power).


I don't know if maybe i am just expecting too much.

 

[Anthony]

I have a 2004 LT and the front is just as cold as the back

 

[T3rry]

does it take time to get cold? i have only the manual fan (will be going e-fan soon) and was only driving for like 5 minutes, but the front had cooled down quite well, however the rear didn't.

 

[Anthony]

it takes about 10 seconds more then the front to get freezing cold in 90 degree weather (about 10-20 seconds for the front)

 

[T3rry]

OK, i'll talk to the guys that recharged me, thanks.

 

[YNOT]

(thread hijack)
can anything get damaged if it gets to low before recharging?

 

[T3rry]

no, it just wont work, if the pressure is too low the clutch just wont engage the compressor

 

[YNOT]

thanks, mine works but it isn't as cold as my blue truck was. i should recharge.

 

[yukonjacks]

One of two problems could exist. Low freon or a bad relay to your a/c compressor. Get a pocket thermometer and put it in your vents the temp should be right around 55 deg on an 80 - 85 deg day. Make sure its not the relay not allowing the cluch to engage. You can temporarily hot wire the a/c off the battery to engage the clutch. Run it for a minute or two to see if the temp drops. If your getting your a/c system recharged ask them to put a shot of dye in the system, you can use a black light to find the leak. Another way to find a leak is check all you fittings for any residual oil. It wont be a puddle, it will actually attract dirt and dust. If you find the leak, make sure you get a replacement freon R134a that has oil in the charging canister.

 

[T3rry]

it's not the compressor, the front AC works fine

it's not low freon, i was testing it as i drove away from the shop that refilled it


i have done some research and i think i have narrowed it down to a bad actuator in the rear vents which is making the temper adjutment for the rear not actually move the flap door thing.

 

[T3rry]

Just did some more testing and changing from heat to cold seems to have no effect as well, so i think i may have nailed it... either that or it's because i removed the rear hvac controls.... damn... i totally forgot about that, i guess i'll have to check that first.

 

[T3rry]

alrght, i'm lost, the actuators are all working fine, i found a large sensor looking thing near the rear fan and removed it, inside i saw what appeared to be an AC condenser... i felt the tubes, and it was not cold, even with AC on and turned up...


any ideas: if this is an AC condenser; why it would not be cooling down?

 

[mdtahoe]

The condenser is in front of the radiator. The truck has 2 evaporators one in the back and one in the front. If the evaporator is not cold and the charge is correct ( read the AC tag under the hood and make sure they put the correct amount in) the rear expansion valve is not working

 

[T3rry]

The condenser is in front of the radiator. The truck has 2 evaporators one in the back and one in the front. If the evaporator is not cold and the charge is correct ( read the AC tag under the hood and make sure they put the correct amount in) the rear expansion valve is not working

ok, i'll check the rear expansion valve... i hope i can fix that without draining the system again.

---------- Post added at 07:22 PM ---------- Previous post was at 07:09 PM ----------

damn, just looking at some reading, looks like this is a rear orfice tube thing, i really wish they;d have had some shutoff valves so part of the system could be serviced without draining and refilling the whole damn thing, this is getting really expensive, i guess i'll call the shop that did it and see if they can drain and recharge it for a reasonable price, given the ****** circumstances.

 

[T3rry]

dealer wants $200 for the rear expansion valve and says there's no way to clean it or if there's a filter i can change out, hes says i have to change the valve... well i guess no rear AC for me... i just paid $250 for my AC recharge, i'm not going to go pay that again to change this $200 part, that's another $500 added to the cost of this damn thing.

 

[mdtahoe]

The shop should only charge you the labor for the drain and refill of the ac system assuming you are going to change the valve your self. Seeing how they just charged it the system should still be full. They can pull it back out and keep it in their machine until you bring it back for a recharge. At least that is what I would due for one of my customers in this situation.

 

[T3rry]

yeah, well it's still $200 for the valve, and what seems like a lot of work, not sure it's worth it for me.

 

[bartman]

i just had to go through all this too, compressor piled up in my 2001 yukon. it is the expansion valve, i did the compressor, drier and orifice tube. cold enough to freeze a guys nuts in the front but the rear blows lukewarm. i did some searching before i did anything and its recommended that you replace that valve when the compressor goes but i cheaped out. i don't care, don't ever sit back there anyways.

 

[T3rry]

i just had to go through all this too, compressor piled up in my 2001 yukon. it is the expansion valve, i did the compressor, drier and orifice tube. cold enough to freeze a guys nuts in the front but the rear blows lukewarm. i did some searching before i did anything and its recommended that you replace that valve when the compressor goes but i cheaped out. i don't care, don't ever sit back there anyways.

yeah, if i had known about it beforehand, i probably would have done it, but in all the info i read i never saw any mention of the rear valve..

 

[Chads93GT]

dont worry, my rear expansion valve needs replaced too. No rear AC. I deal with it. its not THAT bad. As for how cold, if your ac system is blowing 40 degrees below ambient temp, then its working VERY well. Especially in an area with high humidity, like where i live.