AC, is it up to snuff?

[cybrfire]

How do you know? I don't think it is blowing as cold as some of the newer vehicles. Is it just not as efficient of a system?

I have the cadillac 500 AC compressor. The rest of the system is originally from the crew cab save some hoses.

I have a 16" electric fan that I kick on manually when I turn on the AC to pull the air over the condenser.

I think it is charged with R134A. Just had it charged last week.

 

[919jackass]

you want to be 30 - 35 deg below outside temp on your temp vent. when going down the road you should be right at 35 to 40 deg below ambient temp. with a good vacuum oil charge and freon charge that should not be a problem. they key is a good vacuum on the ac system. when a machine pulls a vacuum on the ac system it boils the moisture out of it that is the key. if you have moisture in the lines and it's charged it will cool but it can create water inside when the gas goes to a liquid. with systems with a exspanion valve it can actually freeze the valve with our systems we have orfice tube it can freeze that tube which will definatly effect ac proformance.

 

[76zimmer]

ditto, I had my 99 evacuated and recharged...it shows 29* at the vent outlet! Once the truck is rolling it helps a bit too....is your condenser clean?

 

[Fordum]

Home units shoot for a 20 degree differential.
Measured at the input to the system and the output vent. And yes, you can get it too cold.
More than 20 degrees will cool the room off too fast and not remove as much moisture.
You wind up with a cold clammy house.
Less than 20, and the unit works too hard.

Autos are not as concerned with moisture, and will usually run cooler. No matter what, the important thing is the differential, not the final temperature.

After all, you can not expect a unit sucking in 95 degree air to give you 35 degree output.

Plus, engine speed, which controls how fast the freon is pumped, and vehicle speed which effects the air flow over the condenser will make a difference also.

 

[blazinzuk]

So I know a guy that had his AC stuff totally redone. This was on a super nice 84 one ton regular cab truck. Guy did a total frame off on it.

He got his AC working and had a question he wanted to ask me about the motor. We drove around a bit I asked him about the AC he currently had. Said he had just spent a bunch of money trying to get it to work. He travels back and forth to AZ sometimes and takes the truck. Said there was no way it would keep up in that heat.

I suggested looking at Vintage Air units, they had just come out with the direct fit units for our trucks. He dropped the coin for the direct fit unit. Put it in. Last year he called me up said that vintage AC works like he put himself directly in a freezer.

It is insane how well that thing works. Spent the same money he did totally redoing his stock AC system.

I know they can put together a custom system for you using the Caddy stuff.

 

[cybrfire]

I'll put an IR in one of the vents here in the next couple days and report back. It's definitely cooler than ambient, just not that impressive. It's been pretty damned hot here lately to. Mid 90's lately and pretty hefty on the humidity.

 

[Big Ray]

you want to be 30 - 35 deg below outside temp on your temp vent. when going down the road you should be right at 35 to 40 deg below ambient temp. with a good vacuum oil charge and freon charge that should not be a problem. they key is a good vacuum on the ac system. when a machine pulls a vacuum on the ac system it boils the moisture out of it that is the key. if you have moisture in the lines and it's charged it will cool but it can create water inside when the gas goes to a liquid. with systems with a exspanion valve it can actually freeze the valve with our systems we have orfice tube it can freeze that tube which will definatly effect ac proformance.

guess my burb without rear a/c is doing better than I think...it'll blow 60" on 95-100" days...

 

[big dan]

My question is, what is the difference in capacities between the Cadillac compressor and the stock compressor?

I wouldn't think that it would be much but the condenser, evaporator, expansion valve and compressor are all designed to work together just like the ac system in your home. If you were to swap a 3 ton compressor into say a 4 ton ac unit it wouldn't work properly.

I would check the outputs capacities of the caddy compressor vs. the factory gm compressor to make sure they are similar.

Like Fordum said, we look for a 20 degree drop between the return and supply air in home systems, I would imagine you would want something similar in your cars ac. If your evaporator temp. is 32 or below you run the risk of it freezing so you don't want to go too low either. Hooking up a good set of gauges, not the parts store quicky gauges that tell you if you're in the acceptable range, but a set where you can actually read the pressures of both the high and low side will tell you a lot about whats going on.

 

[cybrfire]

My question is, what is the difference in capacities between the Cadillac compressor and the stock compressor?

I wouldn't think that it would be much but the condenser, evaporator, expansion valve and compressor are all designed to work together just like the ac system in your home. If you were to swap a 3 ton compressor into say a 4 ton ac unit it wouldn't work properly.

I would check the outputs capacities of the caddy compressor vs. the factory gm compressor to make sure they are similar.

Like Fordum said, we look for a 20 degree drop between the return and supply air in home systems, I would imagine you would want something similar in your cars ac. If your evaporator temp. is 32 or below you run the risk of it freezing so you don't want to go too low either. Hooking up a good set of gauges, not the parts store quicky gauges that tell you if you're in the acceptable range, but a set where you can actually read the pressures of both the high and low side will tell you a lot about whats going on.

Don't have any of the AC tools but the guy I had charge the system for me, he does and I trust his work.

He thinks there may be a leak somewhere so he added some dye to the refrigerant. I'm supposed to drive it for the next week or so and then bring it back to him for a black light test. Looking for the dye I guess. In the meantime, i've made the adjustments he asked me to, manual fan switch and a belt adjustment.

I guess another thing maybe leaks of hot air coming from outside the truck. I'm sure my old rig isn't sealed up as good as some of the newer vehicles i'm comparing to.