So, of course I wait to until it is warm out to look at the A/C. It is working but I'm not sure it is working to full efficiency. This is a '95 w/ R134a. Using my instant read thermometer, I'm seeing 44 degrees at the vent. Is that what I should expect or is it too warm? I would think it would be colder.
A/C Advise Needed (1 Viewer)
- Thread starter Cruzerman
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What ambient temp?
C or F? I would say 44F is very good. Don’t think you’ll get much lower
You can be to cold and freeze the evaporator.
I was working on a car last week vent temps where 65. trouble shooting found the evaporator out put under the dash was about 50.
You can be to cold and freeze the evaporator.
I was working on a car last week vent temps where 65. trouble shooting found the evaporator out put under the dash was about 50.
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Depends on the ambient temp. Actually...the cooling of any system shouldn't really have a 'hard number', there are too many variables involved. Generally speaking...if you have vent temps (windows closed, Air on max, recirculate... to simulate actual cabin conditions when driving) of about 30-35° F. less than ambient, you are doing pretty good. Vehicles with modded fan clutches and Aux fans might do 40° F. below ambient without too much trouble.
The question is: Are YOU comfortable at the temperature it is operating? If so...don't become consumed chasing down a certain vent temp number. IF not...then yes, we can do some testing.
While we are discussing A/C's some food for thought:
* The A/C system on our Cruisers are belt driven. That means system performance is 'variable' with engine speed and air flow. It is not like a home A/C system where the compressor and fan speed are constant. So expect less cooling at low speeds and better cooling at higher speeds.
* Ambient temperature will ultimately determine the cooling ability of your system. Recognize that 'ambient' is to be taken about 1' in front of your condenser. We don't care what the temperature is out at the airport. Also, the ambient temperature measured inside your garage is NOT the same temperature your vehicle see's sitting on black asphalt in a traffic jam. The air 2' above hot pavement on a 100° F. day might well be 115°F
* Solar gain (sunshine coming in through the windows), heat soak (interior components such as seats, dashboard, etc...heated from the sun), radiant heat (from the roof and hood of your vehicle) are all things that can put a load on your A/C system. These are the 'field conditions' that don't exist while your vehicle is being tested in a service bay.
* The thermistor on your evaporator is there to help cycle the system (NOT THE TXV). The TXV is there to get the evaporator as cold as it can. The thermistor has to regulate the cycling of the system to prevent the evaporator from freezing up. So...despite all other parts of a system being in good shape, the thermistor isn't going to the allow the evaporator to get much below 40° F. So if you have vent temps (under any condition) of 38-40°F then it's doing all it is capable of.
Final thought/fact:
There are three things that determine how well your A/C will work.
1. It's original design (all the components and design features engineered for a specific result).
2. Proper amount of refrigerant and lubricating oil (little if any moisture or air).
3. AIR FLOW, AIR FLOW & AIR FLOW. Through the condenser and radiator and then across the engine.
Dissent
Questioning my life choices...
My goal is 44 degrees F with 105 ambient. That ambient temp matters a lot!
Aux fan in many cases will reduce AC output
Pictured with outside ambient ~100° and aux fan running
Pictured with outside ambient ~100° and aux fan running
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^^^^ I want to lose 35 lbs. AND win the lottery by the end of the week, but I'm pretty sure both of us are going to be disappointed.
Hope you get there though.
I think I can get in the high 30's with ambient temps ~100 in my 92 with a never-serviced R12 system. I'll try to check in the next couple days.
Dissent
Questioning my life choices...
@LandCruiserPhil did it, I think it involved a blood sacrifice though.^^^^ I want to lose 35 lbs. AND win the lottery by the end of the week, but I'm pretty sure both of us are going to be disappointed.
Hope you get there though.
- Thread starter
- #10
So I did this in the morning when the ambient temperature was maybe 70 degrees. So this rig is not my DD. However, I'm going on a trip in three weeks to southern Oregon where it gets hot and want to be prepared.
I was wondering if people thought I would gain anything from replacing the expansion valve, cleaning the exchanger unit (whatever it is called), replacing the dryer, and recharging? I have the tools, so not a big expense.
I was wondering if people thought I would gain anything from replacing the expansion valve, cleaning the exchanger unit (whatever it is called), replacing the dryer, and recharging? I have the tools, so not a big expense.
^^^^^
Absolutely! R12 for the win every time. Not so much for R134a though.
My first vehicle in High School (a LONG time ago) was a '66 Mustang GT with a dealer installed under the dash A/C unit. Even on the hottest summer days here in Texas...it would spit little pieces of ice out of the vents (no joke). Of course it was an R12 system.
Mid to high 30's (vent temps) are easily believable with R12 and a good working system.
R12 can see 30° and below
I clean my radiator and condenser every year with a good soaking of simple green. The flush from the inside out and Im amazed the amount of dirt I get considering I pressure wash my 80 over 12 times a year.
Yes, if the ambient was only 70° F. and your vent temp (after running 15 minutes to stabilize, on recirculate) was 44°F, then I'd say there is room for improvement. But I'd much rather have a reading from when the ambient is at least 85°F...before passing final judgement.
Hah, just checked the weather. It's 10:00 p.m. here and still 93°F.
I did hear that you guys were having a heat wave though. That would be a good test for it.
Lol. Yeah, it was 100+ here today in Medford.
First thing to do if you have the tools and want to do it right is put a set of manifold gauges on it and check the high/low pressure readings. FSM has plenty of spec's and troubleshooting info.
I've purposely stayed R12, and encourage others to do so when possible. Refrigerant is still available on ebay, and while expensive, if done right you'll never mess with it again.
As mentioned, my 92 is still untouched. My 91 needed topping up every couple years, and then I finally had a shop give it a good once over (replace seals and dryer, pull a vacuum, and recharge) a couple years ago, and it's good as new. They were fine with letting me bring in my own R12 and using that.
Dissent
Questioning my life choices...
- Thread starter
- #19
So I drove the cruiser to work today. On my way home I ran the A/C. It was in the low 90's out and the drive is about 45 minutes. I saw temps between 42 and 46 degrees. While not as low as I had hoped for, I'm good with it for now. I got other projects I would rather work on so we're going to call this one good for now.
Thanks everyone.
Thanks everyone.
Two years ago I took mine for full inspection of AC system. As I have 2 ACs and ice box contour. In ambient temperature of ~40C AC technician made the system output on the air port 8C. Therefore after engine swap I am looking to upgrade the AC system and come up with ~1-2 C. That's my goal, I got my hands to almost twice bigger compressor and working on fitting it.
