So i picked up a old Engel 12v fridge/freezer to use in my Land Cruiser for multiday trips. Kind of like this but much older.

https://www.westmarine.com/buy/engel--34qt-portable-refrigerator-freezer--11589454?cm_mmc=PS-_-Google-_-GSC%2520-%2520Product%2520Type-_-11589454&product_id=11589454&adpos=1o3&creative=108421552084&device=c&matchtype=&network=g&gclid=EAIaIQobChMI2__rpLLi1gIVDVmGCh0-Hw0eEAQYAyABEgICrfD_BwE

The guts of the system are basically like a mini fridge. I got it for for cheap and it does work, just not super cold. I will pick up a  thermometer tomorrow for some real numbers. But but i have it running about 7 hours our in my truck. it was definitely "cool". The compressor was still running the whole time. The compressor was warm, almost hot but you could put your hand on it for a long time no problem. The condenser was barely warm, probable mostly heat from the compressor. The cooling block or whatever it is called inside the cooler was cool to the touch. A few areas of the copper tube before it enters the enclosed cooling element were frosted up. So things are definitely "working". I just dont know if they are getting as cool as it should. Like i said i will get a thermometer tomorrow and let her run.

I have vacuumed and charged auto AC systems before using a manifold. I know enough to be dangerous. I see that the compressor has the pinched off fill line on the bottom. Could i solder on a valve to that fill line and hook up my AC manifold, check pressures?

The system right now has R12 in it according to the label. I think i might actually have a few cans of real r12 at my dads place but i need to look. If i do could i refill it with the proper amount of R12?

The other option would be to vacuum the system and refill it with 134A.I know the oils of R12 and 134A dont mix well. If i wanted to fill with 134A how could i flush the oils other than just vacuuming the system down?

Or does it sound like they system is working as it should and i should just let it run?  Really just looking at ideas and trying to see if anyone here has experience with appliance repair, mostly older R12 systems and converting to 134A.

It's dead Jim.

Even full size fridges are DOA when the juice runs out.

I’d start by cleaning the coils with coil cleaner and see if that helps. They may look clean but they aren’t.

Where did the R12 go?  It's such a small charge, you will need a scale to get it right. And the R12 is going to cost more than a new fridge.  There were some replacements, but they had special requirements and limitation. And most if not all of those are no longer produced. Go to Walmart.com and order a new one. R134a will not work. Different oil , cap tube will be wrong and condenser won't be big enough. 

Eta: you might have other problems like an inefficient compressor or blocked cap tube. If it's R12 it's at least 25 years old.
Walmart

i called it a mini fridge because mechanically that is what it is. But if you look at the link the ARB, Engel and other good ones are about $800. So i would like to get it working if i can. If i cant then that is that and i will move on. But it is worth looking into flushing the system and soldering on a valve and charging it up. But i know there are other people here that know a lot more about this than i do. So that is why i am asking.

PS i have to check the shop but i might even have a few cans of old R12 on the shelf.

If your sure that the coils are clean,  that the fan(s) are operating properly and the compressor is working then sure you can recharge it.    Don't braze a fitting on it unless you can purge it with nitrogen even then just get a saddle / piercing  type.   recover the refrigerant that is in the system for recycling, pull a vacuum and weigh in new.  YES  weigh in per the nameplate or MFG spec. it will be only a couple ounces.    its the only way to get it right with such a small system


Craigslist used to be a good source for R12.  Good prices can be found for a single can if you look and wait.   Another option is to look for a R12 replacement like freeze12 on amazon or eBay.  You can even get 6oz cans

i think it says 48g of R12 on the plate but i will need to go out and look. But yes, not much at all.

Do the piercing type valves actually seal well? isnt it better to solder a valve in?

Piercing valves leak.  Solder on a service fitting. Actually to trouble shoot, you need one on the discharge side also. The problem you will run into though, is the small amount of refrigerant. 48gm is about 2 oz. My 60 in service hoses held about 1 oz of liquid refrigerant. Unless you use self sealing house fittings, your charge will be messed up. You will have to precharge the hoses and don't connect the high side after you weigh in the charge. 

But before you get to that point, you have to rule out other factors. Since it is working somewhat, what makes you think that it had a leak? How much of the evaporator is flooding?  What is the temp of the flooded part odd the evaporator? If it's -10* or lower I would say compressor is probably ok. If not, the compressor could have worn rings or valve issues. If it is -10* or lower,  you probably have a restricted cap tube. Usually it is wax that comes from the oil when overheated. I don't know how yours is put together but you will have to take both ends of it lose and flush it. A product calls Supco 88 works pretty good. It might not be wax. You will probably have to replace it then. You will need to size it, ID and length. I have much experience with this process and that is why I suggested replacing it. I've torn into equipment and cost customers hundreds and thousands trying to save the piece only to have repeated call backs and loss of product. I left a link to the same type of cooler in my previous post that will save you a lot of headaches and maybe your health if you trust your food in your old cooler. Here it is again 48 qt Freezer Cooler

Yes

Thanks for the great info. I picked up a cheap thermometer an will see how cool it gets in how long. That will give me some kind of idea if it is cooling at all. After that i will clean the ouside of the condenser. I think i had a hand held inferred thermometer some place. I guess i could measure the temp of the evep that way.

If it matters the compressor uses a "swing motor" design.

not worth it.  
i do refrigeration, and with the time, material, etc, buy a new one.

its not cost effective.  if you have r12 kicking around, cut the liquid and suction line, braze in a T, and add schrader ports to service it. charge it based on temps and pressures.

then itll leak out again, unless you find the leak and fix it.

i bet the cap tube could be clogged too.  then to fix that, takes experience.

If you get a good piercing valve then you'll be ok.   Are they as good a brazing one in.....  No      but even if you do it with an inert gas like nitrogen the oil already in the line will burn and cause problems of its own.   Get a properly sized "C&DValve" line tap.  don't over tighten an  avoid the ones that have the three screws and are made out of  pot metal   Later on down the road you can install a braze on saddle port using the same hole

Side note,  You used the word "SOLDER"   Brazing with with sil-fos (or equivalent) is not the same as soldering.    Don't use plumbing solder on HVAC.

Yes you do see that i keep saying solder. That is becouse originally i was planning on soldiering... and yes with plumming solder LOL!

I make no claims of knowing what i am doing. But i have been learning a ton, reading and watching videos. Watched a great video about brazing, temperatures, wetting and so on. The more i learn the more i realize that this might be outside of my skill set. But thats cool. I am having fun and learning a lot just looking into it all.

Nah..   the best way to learn is to jump in feet first and get excited about it.   I'd say your on the right track.


Before you make a mountain out of an ant hill you might just want to try for a lucky swing at it.    Put a properly sized / good piercing Valve on the suction line and shoot a half oz into it and see what it does.   if you think it made it a little better but needs more then shoot another half oz into it.    Make sure you purge your charging hose first.       you might get lucky.    worst case scenario you still have to recover it.

You can solder it, it'll be fine.

I still see hacks soldering commercially with 404a. It's scary to work near, repipe, etc but it does hold fine. It's not right, but it works. especially at 3am and you have no braze in your van...

The small lines used can be soft soldered.

It is larger suction line that require brazing.

By the time you pay for fittings it is rarely worth the work and the gas.

I can get a decent price for any of the few cans of R12 I still have sitting around.

Great learning XP.

I would try to shoot some R12 in it if I had it--with a piercing valve--and use it until it dies.

Then sell the rest of your R12 and buy a new one.

Win/win.