Ac hot air

Bostonjohnny

Original poster
Member
Jun 16, 2012
4
First, thank you for all the information here. It has been very useful. I am new to the community and have tinkered around with cars since high school in the '80s. I have hada few suburbans roll through our family. Currently we have an '05 trailblazer ext lt that is blowing hot air. The actuators have been changed and are functioning. The compressor clutch is engaging, or at least going on as evident by it spinning. The pressure is good and the low pressure switch has been changed a few days ago. I am wondering what I should do next? I do have a new relay coming in tomorrow, but I swapped out the current one with another and that did not help. Checked fuses and they are fine. Took it in to the shop and they said the compressor needs to be replaced, $1000. Any suggestions before I commit to a new compressor? Thank you and I am glad to be apart of this forum. :smile:
 

The_Roadie

Lifetime VIP Donor
Member
Nov 19, 2011
9,957
Portland, OR
If the compressor clutch is engaging, it can't possibly be the low pressure switch or the relay. But if the low pressure switch and your pressure test show there's refrigerant in there, you'd think at least the receiver/drier would get chilly. Does it? If it does, but there's no cold airflow inside, then you might have a clogged up evaporator or two bad temp actuators (not likely). If it doesn't, then perhaps the compressor is dead inside. Did you check BOTH high and low pressures? Were they different?
 

Bostonjohnny

Original poster
Member
Jun 16, 2012
4
Thanks for the reply. I did take it in to the dealer and they found it leaking - from several areas. First the compressor is leaking. Also the rear evaporator core is leaking. The said the low pressure switch had a leak too. I advised them that I had just changed it out so the dye may be there form the removal. And a leak from the low side valve core. Wonder is I can just set some ice in front of the vents for cooling???
 

c good

Member
Dec 8, 2011
533
We need some actual high and low side pressure readings, when the compressor is confirmed to be engaged and running before going any further. Even if it needs a new compressor.....$1000 is way too high to pay to replace, evac, and recharge. I did my whole system for under $350.00 (salvage yard compressor $75.00(off of a vehicle with comfirmed low mileage, approx. 30k miles). Approximately $280.00 to remove and replace compressor, evacuate and recharge system. HTH c good

update, after reading add'l, just posted info. The rest of these problems are fairly easy fixes. Even the rear evaporator shouldn't be a deal breaker.
 

Bostonjohnny

Original poster
Member
Jun 16, 2012
4
I was just going to test the limits of duct tape. I would prefer to this job mostly on my own and am somewhat confident on the compressor but not too sure about the rear evaporator. I'll take a look at it. Thanks for replying. I would love to save the money!
 

c good

Member
Dec 8, 2011
533
Duct tape will work wonders!! :smile: :smile: But has limited sucess with High Pressure AC systems. You need to ask your shop to show you where the evaporator in the back is leaking. Evaporators rarely go bad. If they do they will show oil tracings in the core. More often when an evaporator is leaking, it's an o-ring at the tubing connections. An easy and inexpensive fix. Seriously, AC systems are not hoodoo voodoo. Very easily repaired once the problem has been identified.
 

AbsoluteZero

Member
Nov 21, 2011
211
Seems strange that a system would have leaks at multiple locations. You might want to invest in a UV light to confirm/locate the exact areas rather than a verbal description from the dealer. Do you think they were inferring the cause of your problem of blowing hot air was low refrigerant from the multiple leaks? Keep in mind if the refrigerant is very low the compressor won't engage.
 

Bostonjohnny

Original poster
Member
Jun 16, 2012
4
After reading more posts here on ac issues (boy, there's a lot of them), I went for a second opinion. Strangely enough, they could find no leaks. Just said it was about a pound low. They charged it and kept it over night and checked ago in in the morning. No leaks noticed. Added a little red angel and we took it home. Someone just earned my business in the future, for all four of our cars. Thanks for all the input. I put the duct tape back on the wall.
 

oh05ext

Member
Dec 7, 2011
166
on our 05 ext we have several pinhole leaks in the small hose going to the rear of the truck right under the pass seat inside the insulation.apparently its a common problem.i tried for shits and giggles to fix ours with quick steel and it didnt do anything.i have a new hose on order and its gonna be fun to replace that beast.or does anyone know if you can solder over the aluminum line.we just took a trip to hilton head with no a/c and it sucked.View attachment 21527
 

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The_Roadie

Lifetime VIP Donor
Member
Nov 19, 2011
9,957
Portland, OR
Can't repair that kind of line. You need to lift the body off its mounts to replace the entire thing, cut out the bad parts and hose around it (semi-ghetto trick), or hose bypass the entire rear section and live with the front.

Dealer says:

Bostonjohnny said:
...I did take it in to the dealer and they found it leaking - from several areas. First the compressor is leaking. Also the rear evaporator core is leaking. The said the low pressure switch had a leak too. ... And a leak from the low side valve core. ...

Then you make a very smart move:

Bostonjohnny said:
...I went for a second opinion. Strangely enough, they could find no leaks. ...

View attachment 21528

It's no longer strange. Nowadays, it's the new normal.
 

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