Make the AC better!!!

Nero

HD Diesel nut
Joined
Jan 3, 2022
Posts
803
Reaction score
625
Location
OR
Hey all, so I'm no stranger to AC, I've converted mine, my dad's truck, and his old 1988 black truck from R12 to 134a. The black truck, it would absolutely freeze you out. Nothing special done when converting it, just the usual replace the expansion valve, replace receiver, and all O rings.
When I converted my crew cab and my dad's crew cab, I did the same. His cools pretty sufficiently, but not as good as the 1988. My truck however, is just kinda... Meh. It's cooler than ambient, but it's sort of a toss up which is better, roll down the windows or run the ac.
I've already done the usual, pull the evap and make sure it's clean, replaced the condenser, and pressures look good.
Is it possible that just a 30 year old compressor is just plain worn out?
 

Jesus Freak

Full Access Member
Joined
Apr 3, 2022
Posts
1,487
Reaction score
1,156
Location
Crestview, FL
Hey all, so I'm no stranger to AC, I've converted mine, my dad's truck, and his old 1988 black truck from R12 to 134a. The black truck, it would absolutely freeze you out. Nothing special done when converting it, just the usual replace the expansion valve, replace receiver, and all O rings.
When I converted my crew cab and my dad's crew cab, I did the same. His cools pretty sufficiently, but not as good as the 1988. My truck however, is just kinda... Meh. It's cooler than ambient, but it's sort of a toss up which is better, roll down the windows or run the ac.
I've already done the usual, pull the evap and make sure it's clean, replaced the condenser, and pressures look good.
Is it possible that just a 30 year old compressor is just plain worn out?
That's my guess. I know MY compressor is wore out.....WHEWWW!
 

Nero

HD Diesel nut
Joined
Jan 3, 2022
Posts
803
Reaction score
625
Location
OR
Compressors can be a bit spendy, hence why I'm trying to get input before pulling the trigger on one.
When yours was wore out, how could you tell?
 

Jesus Freak

Full Access Member
Joined
Apr 3, 2022
Posts
1,487
Reaction score
1,156
Location
Crestview, FL
I was kidding, I mean like I'M wore out. But really, think about it: it's basically a 30yr old aluminum engine, pistons, rings, compression, friction, heat, etc. Just like my wore out motor burning oil, compression could be low, worn rings could let the coolant " blow by".....makes sense, seems logical.
 

gnathv

Full Access Member
Joined
Oct 18, 2007
Posts
975
Reaction score
444
Location
Athens, Al
If your pressures are correct your compressor is working as it should. If your pressures are low then I’d suspect a worn out compressor. How do you compare to these pressures?
 

Attachments

  • 08D9217B-EEE3-4AF3-B1FF-4321E2805EB9.jpeg
    08D9217B-EEE3-4AF3-B1FF-4321E2805EB9.jpeg
    80.1 KB · Views: 32
Last edited:

Cubey

Full timer RVer
Joined
Oct 18, 2017
Posts
3,621
Reaction score
1,329
Location
USA
My RV got converted to R134a somewhere around 2000-2002. It slowly leaks the refrigerant but it still blows cold when it's reasonably filled. I didn't roast alive driving in 90-100 degree temps over the past several days, despite the heat that comes off of the doghouse cover, and when I stopped, the overall temp inside wasn't horrible (87-92 depending how hot it was outside), so I think it's safe to say it works pretty well. One vent blows on Lucy and she doesn't pant if the AC is on. On steep grades where it had to be turned off, she would pant after a while.

It's probably the original compressor, but then again who knows, it might have been replaced at the time of conversion. That still makes it 20-22 years old, if it was. It's at 83k miles now, and an oil change sticker from 2002 shows 53,4XX, so, it hasn't seen a ton of miles in the past 20 years. Almost half of those 30k miles were put on it by me over the past 3.5 years: 13.2k
 

Big Bart

Tow&Slow
Joined
Dec 22, 2020
Posts
1,481
Reaction score
922
Location
Newport Beach, CA
Hey all, so I'm no stranger to AC, I've converted mine, my dad's truck, and his old 1988 black truck from R12 to 134a. The black truck, it would absolutely freeze you out. Nothing special done when converting it, just the usual replace the expansion valve, replace receiver, and all O rings.
When I converted my crew cab and my dad's crew cab, I did the same. His cools pretty sufficiently, but not as good as the 1988. My truck however, is just kinda... Meh. It's cooler than ambient, but it's sort of a toss up which is better, roll down the windows or run the ac.
I've already done the usual, pull the evap and make sure it's clean, replaced the condenser, and pressures look good.
Is it possible that just a 30 year old compressor is just plain worn out?
Ditto on what gnathv said, if pressures are good, compressor is working.

Did you change out the orifice tube? They tend to clog up over time and prevent the A/C from working at an optimum level. You should replace them when doing a a/c service.

Is your condenser clean? You might want to wash it off and re-check.
 

Isaac Ristow

Full Access Member
Joined
Jul 11, 2018
Posts
222
Reaction score
143
Location
Somerset Wisconsin
Whata your high pressure at? Did you put a red orifice tube in for a 134 truck? I'd replace the compressor especially if it cools better revved up than at idle. Fan clutch needs to be working good too. I replaced every component in my 84 and it blows 28-34 degrees depending on ambient temp.
 

Nero

HD Diesel nut
Joined
Jan 3, 2022
Posts
803
Reaction score
625
Location
OR
I used a red orifice when I converted it, and I pulled it out and inspected it before recharging, it's clear.
I can hook the machine up to it later and check my pressures, when I charged it, I did it on my lunch break so didn't have enough time to do a diag run on it.
Condenser is clear, I actually replaced it last year.
 

Jesus Freak

Full Access Member
Joined
Apr 3, 2022
Posts
1,487
Reaction score
1,156
Location
Crestview, FL
Whata your high pressure at? Did you put a red orifice tube in for a 134 truck? I'd replace the compressor especially if it cools better revved up than at idle. Fan clutch needs to be working good too. I replaced every component in my 84 and it blows 28-34 degrees depending on ambient temp.
GOOD NIGHT!!!! 28-34 degrees! I'd get pnumonia!
 

WrenchWhore

Registered User
Joined
Jun 2, 2022
Posts
92
Reaction score
68
Location
Lake Havasu City
Also remember that these trucks don't have air filters or at least mine didn't on my 84 and my 87. When I pulled the blower motor to fix an air leak it was filled with junk like leaves and dirt and dust that have really choked the flow down making the AC not so good. I stuck a shop vac inside and sucked out whatever was easy then scrubbed it with a gentle tooth brush to loosen up the compressed dust/silt/dirt in the evaporator and kept hitting it with the shop vac a bunch of times. One of these winters I want to pull the blower box and thoroughly clean it. I know this isn't really answering your question but air flow can be another factor in this.
 

Nero

HD Diesel nut
Joined
Jan 3, 2022
Posts
803
Reaction score
625
Location
OR
I replaced the blower motor when I had the evap out to clean it, however I think the air flow has always been a little on the slower side compared to other trucks. I'll tear it off and check it out.
 

papadiesel

Full Access Member
Joined
Feb 8, 2016
Posts
159
Reaction score
72
Location
Indianola, IA
in case I missed it you need to also make sure that your AC door is opening all the way into the cab there is a vacuum actuated door control right above the kickplate on the passenger side inside the cab that will break or quit and when it does it will not allow the door open fully or AC also the air actuated AC air pot on the passenger side inside the engine compartment make sure it moves fully open and closed when you put it in AC mode I have an 89 that blows ice cubes but did not inUntil those two valves were replaced or actuators whatever you wanna call him
 

Joezam

Registered User
Joined
Jan 17, 2022
Posts
13
Reaction score
8
Location
Nevada
Your problem is the clutch switch. It is set for r12, it can be adjusted for r134, simply unplug the wiring and adjust the screw out a 1/4 turn.
 

Nero

HD Diesel nut
Joined
Jan 3, 2022
Posts
803
Reaction score
625
Location
OR
I forgot to mention, I took a clutch switch off of a 1996 that ran 134a already, and used it on both trucks with good results.


I'll have to check the door vac controls, something I haven't tried yet. My truck has mechanical controls, minus the one vac door, whereas my dad's has vacuum doors.
 

Forum statistics

Threads
89,955
Posts
1,103,649
Members
23,013
Latest member
yseguy
Top