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I had my Old Air A/C installed and filled in my 55.2 Chevy and found out that the mechanical fan doesn't pull enough air to keep the condenser cool. So I installed a big 3,000 cfm electric fan and now there is no way the engine or condenser can complain! Only problem is that the A/C is not blowing as cold as I had envisioned. I was expecting ice cold air, but only managed a semi cool breeze. Any ideas on why? I live in Florida and today was very hot and very humid. When I stopped the A/C drain was dripping some serious water so I know it is trying to do its job.

Any input would be great before I have to take it to the A/C shop again.

Here is a video of the A/C.
A/C in 55.2 Chevy truck

Thanks.
Michael

might need to check and see if it is filled as required.
I have vintage air in my 52 sedan and it does great,
in fact went for a cruise this morning and all is well,,, and it is hot in Tx today....

you might put a thermometer and check the air coming out and
see if it meets what is expected..I would think some where between 38 F and 43 F

you need to check it while driving.... I have a friend
who has old air and he is not happy with the cooling...good luck

How different is a Vintage Air vs an Old Air system? Is the condenser bigger or something? What would make one perform better than the other?

what makes a chevy perform better then a Phord..
I dont really know if one brand is better then the other, seems like most go with vintage

what kind of reading do you get out of the vent temp... that will tell you if it is working right or not

I would think it would not be hard to cool a pick up if the unit
it performing like it should, last summer I had to turn mine down because the car was so cold.

you have a very nice truck..

I'll check the temp, but it's obviously not cooling like yours. What a bummer. There is a $1,000 dollar mistake...

Is the cab tight and did you insulate any?

I agree with the idea that the system may not be fully charged.

I'm running the Old Air setup in my 54 truck and on the low fan with 50% temp setting you could hang meat in the cab. Your video is informative but I noticed that the compressor clutch was free-wheeling. If the system isn't properly evacuated and fully charged the low-pressure cut-out switch will disengage the compressor clutch. I'd make sure that the tech that charged the system got it evacuated and topped off fully.

Secondly, the 3K cfm fan should keep your engine cool but it may not be cycling enough to draw ample air through the condensor, especially at low speeds. I use the direct drive 6 blade engine-driven fan which keeps air moving constantly through the condensor/radiator and I register 40 degrees at the outlet after 2 years of operation.

You didn't mention how your electric fan is triggered but I would venture a guess that setting (if possible) the fan power-up at a lower engine temperature, would correct the issue. On my setup I added a small pusher fan that can be manually activated to suppliment the engine-driven fan during extended periods at idle.

Summer is here....103.8 F in Lake Wales today!!!!!!!!!!!!!!!!!

Dave

The electric fan should be wired where it runs when the AC is on.

Geez, 103 out in Lake Wales? I guess I can't complain being closer to the coast. We go out there to the Circle F camp every year, when it cooler.
Anyway, What do you mean by the compressor clutch free wheeling? The low pressure switch has not disengaged the clutch. When the A/C is turned on the fan stays on. The cab is pretty tight, so that shouldn't be the problem. I will take it to a tech next week and see if it is full enough. I sure hope that is the situation.

It's good to hear that your Old Air system is super cool. Enjoy that hot weather out there in Lake Wales.

Does it have a site glass on the receiver dryer? If it does check for bubbles, thats a sign of low gas. Does it have a heater in the a/c unit? (heat & cool) if it does block off the heater hoses.

Lots of water means it cooling enough to condense water on the coil, sure it didn't freeze up? They blow warmish air when froze over.

Joe

If you have a sight glass on top of the drier, you can tell if its fully charged by that. Run the engine at a high idle with the air on, blower on high, & a door open. The sight glass should run clear. If it is foamy it probably does not have enough charge.

I agree with the guys that are saying the charge is low, do you know if the place that installed it did a leak test? Also, take a temperature reading in the vent with a gauge like this Temp Gauge for testing A/C. This will give you a good idea of what temps your A/C is pushing out.

I only use my electric fan when I get stopped in traffic
and the temp starts tipping at 215.........manual switch
that will light up my little fan image to let me know if it is on.. dont use the electric fan other wise...no problem with running my air this way............

Dave, nice truck... dual carbs , six cylinder and air... how great is that.

If you are using 134a as a refrigerant if you clear the sight glass it will be over charged. Sight glass works well with R12, but it should be slightly cloudy with 134A.

But it does sound like the system is a little low.

Was just thinking after reading Joe H's comment.......my manual control setup, came with 2 valves that were to be placed in the heater circuit hoses. One was cable-controlled that regulated the volume of flow of hot water through the heater core. The second valve was a simple shut-off valve that completely shut down circulation of heated water in the inlet hose when you screwed down the valve manually.

If you plumbed in the heater circuit you should have some type of shut-off valve in your electronically controlled setup. If by chance you didn't plumb in the heater circuit, you can ignore this info.

As for the "free-wheeling" comment......it was in reference to the first part of your video where the engine was running but the clutch on the compressor wasn't engaged. As the video progressed you kicked in the switch and the clutch engaged and the compreesor did it's thing. This would tend to eliminate the premise that the system was low on a charge and confirm that the low-pressure switch was functioning as normal.

Dave

I looked all over and there isn't a sight glass, that sure would help! Also, I shut the valve on the heater hose. I'm running 134a as a refrigerant. I ran out of time to work on the truck this weekend, but I'll get it into the shop to see about the charge. I hope that is the situation.

Thanks for all the responses! I'll let you all know what the problem was.

The site glass should be clear if the system was designed for 134A, if its a R12 system converted to 134A, then it should be a little cloudy.

Joe

I have yet to work on a 134 A system that someone "cleared" the site glass and found it not over filled.

With 134A you really need to go by pressure (gauges) to make sure it's right. Even better is to use a scale and measure how much you are installing.

Spent the last hour with the A/C tech. Short story is that it works now. Blowing air at 37-39 degrees. I had imagined my truck being like a fridge, but I will have to live with it just being cool enough.

Long story. The first tech put a pound of freon in the system, then noticed there was far too much pressure and stopped. He said to get an electric fan, which I did. I got this one: Flex-Lite Black Magic 180. It fit my 55.2 perfectly and you can actually feel the air being sucked in through the condenser and radiator! Took it back and they filled the freon to 2lbs. The pressure was fine but the air temp stayed at 48 degrees. We called OldAir and they said to reduce the freon a little. The air temp dropped down to 37.8. The A/C guys looked around the cab and decided that I need to insulate the cab better. "It's like cooling a tin can with holes!" he said. So I'll set about doing as much insulating as I can. The temp in FL today is 89 and I was nice and cool in my truck. Makes for much nicer driving experience.

Thanks for all the help!

Michael

Sounds about right. Get it much colder out the vent and it might freeze up the evaporator. Good going.

We do a lot of a/c installs and correcting what others have done. By far the biggest problem on 134A systems are they have been overfilled. Sight glasses should be outlawed. You got a good experienced tech that obviously knew of this situation and corrected it. On the old 12 systems you could get by with thinking it's hot today and the condensor in the sun so 300 or so on the high is ballpark. With 134A you read the chart for ambient temp and humidity and set the high side for the a that reading EXACTLY. The old belief that just a "tiny bit more" will help will drop your output temp by 20*.