A/C in the 80 (1 Viewer)

[Von Hayek]

Rhea's truck hasn't been blowing that cold, and during the heat wave it really hasn't been cooling at all. Tracy was kind enough to lend me a gauge to check the refrigerant level, and it unfortunately looks like it has a good charge.

Ideas? I don't know much about a/c systems and I don't want to just start replacing parts.

Bart

 

[76FJ40]

Is the compressor engaging?

 

[John Smith]

Does the compressor clutch engage when you turn on the AC? It may be something as simple as a failed pressure switch. Edit, Bob beat me to it. Have someone turn on the the AC while you look at the clutch to visually make sure it engages.

 

[Von Hayek]

I think so, only because it does blow cool air when the temperatures aren't in the 100s.

How about the condenser? The previous owner had put radiator gunk in the cooling system and clogged the radiator. Wouldn't surprise me if he put gunk in the a/c system and clogged the condenser.

I'll check the compressor when I get home this afternoon.

 

[John Smith]

If it blows some cold air and you are showing a full charge of freon, it could be the expansion valve. What are your high and low side readings when you have the gauges hooked up, with the AC on? Do 80s have a little window on the receiver / dryer? Do you see bubbles when the AC is turned on?

 

[Von Hayek]

If it blows some cold air and you are showing a full charge of freon, it could be the expansion valve. What are your high and low side readings when you have the gauges hooked up, with the AC on?

Not sure. This is not a mechanic's gauge -- it is the type that you can pick up from Wal Mart for charging the system, and I don't even think it will attach to the high side. I'll have to see if if Autozone has one I can borrow.

 

[Skrewball]

when does it not blow cold? driving/sitting in traffic/both?

most of the time its just a low charge. the condensor seals are very common for leaking.

also, check to make sure that if the compressor is running and the truck just isn't cooling well, that there is water dripping from the drain. sometimes with a low charge/turned down thermostat the evaporator will freeze up after a short period.

 

[Von Hayek]

when does it not blow cold? driving/sitting in traffic/both?

most of the time its just a low charge. the condensor seals are very common for leaking.

also, check to make sure that if the compressor is running and the truck just isn't cooling well, that there is water dripping from the drain. sometimes with a low charge/turned down thermostat the evaporator will freeze up after a short period.

It definitely blows cooler when driving, less so at idle. Sometimes not at all during idle.

 

[76FJ40]

Just tell her to pretend she's driving a 40. She'll be grateful for any cooling at all.

 

[Blue77FJ40]

Totally A/C ignorant here, but just ran across this thread that may be of help.

https://forum.ih8mud.com/80-series-tech/503254-c-vent-temp-too-warm-pics-inside.html

HTH, Dan

 

[Skrewball]

prob a low charge, but what is also very common on the 80's is the need for an aux fan.

i had a problem with my a/c cutting out on long grades and in traffic on hot days. the 80 ecm controls the a/c signal with a temp switch. if the coolant(engine) gets to high then it cuts the a/c off to cool it down.

im not saying this is your problem, just a common one for 80's.

it will be very helpful to see what a set of gauges show on your truck.

check around your local shops, alot of them offer an a/c special which sometimes includes freon.

you should have brought the truck down on sat.!! we have a set of gauges, and i could have told you what was wrong.

 

[Michael Hanson]

First dont hook up to the high side with that small gauge. Second if the charge is full.I would change your reciever-dryer, its prob. full of moisture. MIke

 

[ryngbsn]

Does the compressor clutch engage when you turn on the AC? It may be something as simple as a failed pressure switch. Edit, Bob beat me to it. Have someone turn on the the AC while you look at the clutch to visually make sure it engages.

How do you test a failed pressure switch? The A/C light comes on when the button is pushed but the compressor clutch does not engage...Didn't mean to hi-jack your thread...

 

[Thornton]

Hang a bag of ice off the rear view mirror. Let it dangle in front of the vent and turn the fan on high. Keep a cooler stocked with plenty of ice bags, a couple of cold beers are nice to hang as back up also.

 

[Von Hayek]

OK, a little more info here. Noticed bubbles in the system this afternoon. Factory service manual says to keep adding refrigerant until the bubbles disappear. Just emptied a whole can with no change in the bubbles. The homeowner's gauge that comes with those bottles says I'm at about the max system pressure now, so I'm not sure where to go. Have the system evacuated?

 

[Von Hayek]

Hang a bag of ice off the rear view mirror. Let it dangle in front of the vent and turn the fan on high. Keep a cooler stocked with plenty of ice bags, a couple of cold beers are nice to hang as back up also.

I think I'm going to try and troubleshoot this a little longer

 

[John Smith]

How do you test a failed pressure switch? The A/C light comes on when the button is pushed but the compressor clutch does not engage...Didn't mean to hi-jack your thread...

Using an ohmmeter you check the continuity between the two terminals on the switch. It should read zero.

 

[Cruiser804]

Is it supposed to get cold? who knew...

 

[Von Hayek]

Forgot to update this. Even though there be bubbles still a flowin' after a single-can charge, she be blowin' frigid cold.

 

[StaleAle]

...after a single-can charge, she be blowin' frigid cold.

Ummm...are you referring to the 80, or did you follow Tom's suggestion?