thrashingcows

Thanks everyone!

Well yesterday I figured it was time to get the AC working.

I had cleaned the evaporator, lines and condenser when I had everything apart. I installed a new AC compressor, it was pre-filled with about 5oz of oil. I then read through the FSM ad found that I needed to add another 4oz. So that went in and I then installed a new drier. Closed everything up and ran a vacuum on the system for 30 minutes.

I then installed the 134a conversion fittings, and refilled it with Duracool. The operating line pressures are within proper spec, but I just am not getting the cool temps I should be seeing. Even on the Hwy I am only getting moderately cool air from the vents.

I think this has a lot to do with the AC condenser being behind the Power Stroke Intercooler. It's just not getting the cool air "first" like it needs to properly transfer the heat.

I'm going to install a couple manual shut off valves on the heater hoses to stop ALL the coolant from entering the heater box. Just so you know, even with the vacuum controlled valve on the inlet heater hose to the heater core...you still get parasitic heat drawn into the heater core from the outlet line. Hope this helps a little.

If I can't get the AC temps down where they should be, or where I can live with them, then next spring I'm going to install a remote condenser with fans under the box.

MARF75

Hey Cows, I'm not hijacking just throwing this info out there for yours and others consideration.
I've been wanting to install a/c on my truck for a couple years now and my dad picked up a d250 that is going to serve as a parts donor for me.
My brother in law has been in commercial refrigeration for about 24 yrs so I was picking his brain about converting to 134a. His personal opinion is that 134a is a "junk" gas.
When all these new refrigerants started coming out the company he works for took it upon themselves to do a little experimenting with swapping/ mixing different gases.

He is telling me NP39 is a " drop in" replacement for R12. As soon as him and I get some time we will be installing the donor parts and stuffing them full of NP39 and I will report back to this site with some (hopefully good) info about our findings.

thrashingcows

Thanks for the info MARF....Sounds like it might be a great alternative. Only question I have is, can an average guy off the street get this NP39?

thrashingcows

Playing with the AC again this after noon...100+*F today, and humid as heck!!

Anyway the AC charge was low...turned out the cap on the retrofit adapter valves was a tad too long and it was hitting the schrader valve just enough to allow it to slowly bleed off....DoooHHH!

So got that figured out, then charged it back up. Still only getting tepid air out of the vents. Was checking the Heater hose shut off valve, and it seemed to be working properly, but I thought I may as well just remove it and double check. Well it wasn't stopping any coolant flow. It would move properly, and appeared to be functioning, but whatever was inside the valve to shut down the flow of coolant was rotted, or missing. I had another valve...but it was the same. So the coolant lines got disconnected and looped together.

So we will see if the AC works a bit better now that I don't have steaming hot coolant entering the cab.

So those who are having cooling issues with your AC...try checking this valve first. Even if it "appears" to be working, it very well might be non functional inside.

mknittle

Hope that does the trick. Every big truck that I drove had a manual valve substituted for the inline valve. some were ball valves others were gate valves etc.

j_martin

If you want cooling performance that slightly exceeds R12, use a mixture of 71% propane and 29% iso-butane (not the same as lighter fuel, found in mountain stove fuel.)

I've found that 8 oz can of MSR iso-pro and 14 oz. of Coleman propane is about right. You can mix it in the system by evacuating the system, then dumping in one can of iso-pro, then 14 oz of propane. Takes about half as much by weight as R12.

Running the condenser after the intercooler would not be good. System was designed to run the condenser first. R134 pushes the design to it's limit. With C12 (the above mix) you might be able to get away with it.

thrashingcows

Thanks for the advice....I will keep that in mind, and might give it a try.

What kind of adapters do you use to mate the cylinders to the A/C system?

j_martin

The USA is finally getting around to putting propane in domestic appliances. GE has some out already. The only reason for the ISO-butane in this mix is to hold down condenser pressure to R-12 levels. If the system were designed for it, pure propane is better.

For years Dupont et al had the regulators convinced that less than a pound of propane that might leak out of a refrigerator was a deadly explosion and fire hazard while the cook stove with manual valves hooked to a tank with 2000 lbs of propane in it is acceptable.

Anyway, I adapted a 1" throwaway propane tank adapter with a gate valve and a flare fitting. (5/16" I think) I found an old clip on piercing dispenser that was used on the 1 lb R12 cans, opened up the throat slightly with a die grinder, and use that on the MSR cans. It's a little hard on the lindahl valves, making it a one shot dispense, like the freon cans were. Works well enough.

For a single evap automotive application, I just dump in the two cans like I said. For bigger systems, or a refrigerator, air conditioner, etc, I pre-mix into a used 20 lb freon can with a decent valve welded onto it. Be careful, be sure it is completely evacuated and then do it outside with the wind to your back. A little phosgene can make you very sick or dead.







There is a proper valve for the 7/16" lindahl valve on the iso-pro cans available, but it's pricey and still has to be adapted. It's either a 1/8" pipe, or maybe a compression outlet. It's available here:
http://www.ministeam.com/acatalog/Burners-p5.html

thrashingcows

Thanks again J-Martin for that great advice and information!! I will probably give it a try and see how the combination of those gasses work with my system.

So I Went for a bit of a drive today...110*F out there today! I was getting cold air, but I think the cab of the truck only got down to around maybe 72-75*F? It was comfortable, but not cool in there.

I was concerned a couple times because I heard this roaring sound. Turns out my fan clutch is working just fine...it's locking up into "Severe Duty" and pulling a ton of air.

j_martin

These trucks aren't famous for meat cooler temps. I'd say it's doing pretty well. 72° with a low dew point is pretty comfortable. Colder is actually unhealthy for ya. C12 should perform better than R134 under these conditions.

When the high flow fan kicks in, it can get pretty noisy. The only time I've heard mine is if I'm really burning fuel pulling something big and heavy at speed in hot weather.

thrashingcows

OK I decided to try and be lazy....I ordered one of those H4 headlight relay kits off E-bay. Wondered about the quality of these kits so I paid $15 shipped....so not out too much.

Here are a couple pics of the kit I ordered....





Well decided to install it quickly and see what happened. My 93 donor was a Canadian truck, so it came with the daytime running lights...which still work properly. So I hooked up the system with the primary hook up on the passenger side, since that is where the main power for the DRL come from.

The high and low beams seemed to work fine. But when I shut off the lights, and then moved the truck to get the DRL to come on..(Yup it needs to sense movement or they will to come on). The relays in the system were buzzing like crazy, and only the drivers side would light up. The passenger side was very, very dim...just a slight glow in the bulb.

thrashingcows

So guess it's a no go. But what really got me was that I was feeling the wires, and even though they looked like 10/12ga...they were really soft. So I decided, since I was not going to be using the kit, to open up the main power wire. Wow what a deception they have going on there!

Here is a 10/12 gauge piece of wire on teh left, and the "10/12ga" wire from the kit on the right.



I actually measured the wire strand and if it's 18ga I think you'd be lucky. All coating on the wire to make it look bigger then it really is.

oliver foster

With a name like CHeeSKY, I would be wary too.

mknittle

typical Chinese product the box looks better than what's inside.

crazy clem

If you dont want to build your own the painless kit is high quality but not as cheap as the sumpilopoo kit