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Tim Mohr
Tim Mohr, ASE MASTER TECH
Category: GMC
Satisfied Customers: 15121
Experience:  30 YRS EXPERIANCE, AUTO AND TRUCK,FOREIGN AND DOMESTIC, GAS AND DIESEL
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2011 Acadia awd 3.6 need help with getting the Ac working

Customer Question

2011 Acadia awd 3.6 need help with getting the Ac working its cycling off and on the low and high pressure act weird
Submitted: 7 months ago.
Category: GMC
Expert:  Tim Mohr replied 7 months ago.
Hi, my name is ***** ***** are the high and low pressures when the a/c is on, and idling?
Customer: replied 7 months ago.
30/200
Customer: replied 7 months ago.
After running for a couple of minutes its 30/250
Expert:  Tim Mohr replied 7 months ago.
how much freon, if any, have you added?
Customer: replied 7 months ago.
Im not sure you think i should vacuum it all out and recharge?
Expert:  Tim Mohr replied 7 months ago.
that would be the only way to know for sure the charge is correct, is it cooling at all?
Customer: replied 7 months ago.
Not really it cycles off and on about every 10 seconds
Expert:  Tim Mohr replied 7 months ago.
what all have you done? how did this start? was it not cooling at all this spring?
Customer: replied 7 months ago.
The ac did work but one day i tried to turn it on and the ac light would just blink
Expert:  Tim Mohr replied 7 months ago.
ok, with the a'c on, and idling, can you feel the aluminum lines at the firewall, and tell me if they get cold?
Expert:  Tim Mohr replied 7 months ago.
Are you still here?
Customer: replied 7 months ago.
Yeah give me a little bit
Expert:  Tim Mohr replied 7 months ago.
no worries
Customer: replied 7 months ago.
With the car off for a while both high and low equalize at 65
Customer: replied 7 months ago.
The hose is cold
Customer: replied 7 months ago.
The air coming out of the dash is 40*
Expert:  Tim Mohr replied 7 months ago.
it will eventually equalize, if the lines are cold at the firewll, but the air is not cold coming out of the vents, then you have a bad temp blend door actuator under the dash, it wont be anything under the hood, have you checked the actuator yet?
Expert:  Tim Mohr replied 7 months ago.
what is the outside temp?
Customer: replied 7 months ago.
63
Expert:  Tim Mohr replied 7 months ago.
40 degrees is good coming out the vents??? ideal is 38, but for is definately good, whats the temp out the vents when driving?
Customer: replied 7 months ago.
On all my my other cars the air coming out of the vents is like -8
Expert:  Tim Mohr replied 7 months ago.
celsius or Far?
Customer: replied 7 months ago.
F
Customer: replied 7 months ago.
Im using a infrared thermo
Expert:  Tim Mohr replied 7 months ago.
if it was -8 it would freeze up the evaporator, the computer would shut off the compressor if it was below 32???
Expert:  Tim Mohr replied 7 months ago.
38 is the ideal temp out of the vents, you need to use a regular a/c thermo on this, the infrareds will not be acurate on air flow,Tim
Customer: replied 7 months ago.
Ok ill get one and let you know
Expert:  Tim Mohr replied 7 months ago.
let me know,Tim
Customer: replied 7 months ago.
Its bouncing from 45-47
Customer: replied 7 months ago.
How many oz does this system hold? Do you have to put pag oil in when you vacuum the system?
Expert:  Tim Mohr replied 7 months ago.
this holds 37 ounces of r-14a, it is not necessary to add pag oil, if you are just evacuating the system, evac it and recahrge it and let me know how it works,Tim
Customer: replied 7 months ago.
Thats the only way to get a good starting point i think
Customer: replied 7 months ago.
Ok i vacuumed it and filled to 37oz still doing the same thing off and on
Customer: replied 7 months ago.
The low pressure switch stays closed is that right?
Expert:  Tim Mohr replied 7 months ago.
Yes, theb low pressure swich will be cloed unless the pressure drops below 20 psi, then it opens, turning the comressor off, what are the pressures now, with the correct charge, both idling and driving?
Customer: replied 7 months ago.
With the car at idle it would stay around 30 on the low and 150-200 on the high side it would only run for about 5 seconds . I also found a hose leaking i need to fix what do you think keeps making it shut off?
Customer: replied 7 months ago.
How many hours does it call for to replace the expansion valve?
Expert:  Tim Mohr replied 7 months ago.
These will cycle off, when the pressure gets low, 30 is not too low, so your freon is good, the compressor cycles to keep the evaporator from freezing up, the compressor is not suppose to stay on all the time, what is the temp out of the vents, when the low is 30 ?