Hi! Let me start with a double apology, First I'm not sure I'm in the right section so if I'm not sorry! And also I'm sure there is already a thread on that subject but I couldn't find it So here's my question : I have a 76 Mercury Comet 4.1L straight 6 with Factory AC, the previous owner unplugged the unit as he ran out of gas, what should I do to make that AC operational again? Like to convert it to the modern kind of gas to put in now? Thanks!
If I were to do it: New/rebuilt compressor New receiver/Dryer New hoses New expansion valve. Have a shop put vacuum to it to test for leaks. Charge it with R12 if you can find it. Look here to get an idea as to part pricing: http://www.rockauto.com/ Considering where you are located and the cost for parts: Make sure the compressor is not seized Put vacuum to it and see if it holds. If you want to change to a different gas, you will need to flush the system since the oil will not be compatable. Micah
R12 does work better but I would switch to R134 based solely on availability. If you have issues in the future you may and up doing then anyway.
thanks guys for those precious information! Will look into pricing cause right now with 102° outside I'm dying on my vinyl sits hahaha
I upgraded my setup to an entire kit from Classic Auto Air. Which ever you do, remove the heater box and have the evaporator tested for leaks; if it is leaking you will have to do it anyway. Most likely most of the metal parts in the box will/should need attention "rust". Also, replace the heater core while the box is out of the car.
The old copper brass heater cores can usually be tested and repaired by a good radiator shop and they work better than the newer aluminum replacements. The early copper tube evaporator a can be repaired as well. As for the AC, if your hoses are original, they're likely going to leak and R12 is ridiculous in price. AC shops can make hoses fairly reasonably if you can find a reputable one in your area. If I were starting where you are knowing what I know now, I would replace the condenser with the largest parallel flow condenser you can fit up front, have hoses made, get a decent receiver dryer with a high pressure cutoff switch and if dollars allow, use a Sanden compressor rated for R134a. The money you would save not replacing hoses will be more than made up for in replacing refrigerant every couple of months, especially R12. Sounds like a lot but it's not that complicated with a good game plan. Critical things to remember about a conversion to R134a: 1. R134a needs a larger condenser and good airflow for the best performance. This alone is the most likely reason for R12 "working" better. R134a systems can work just as well if done right. You've gotta get rid of the heat. 2. The correct refrigerant charge. 80-85% of the R12 charge amount is a good place to start. More is NOT better in this case. Getting as much of the R12 mineral oil out as possible is important as well. Most car systems will not need more than 9 oz total oil charge so be careful not to over do it. 3. Educate yourself about the process and AC operation. Vintage Air has a great tutorial that can help anyone who wants a little more information on the subject and is a good source for parts including line kits, should you decide to go that route.
honestly i was expecting something less "invasive" in the "modernizing" process hahaha Once again, I'm glad I asked my question here before heading on, I will look into it taking all of those points into consideration! Quick kind of related question, my heater works fine, but the hot air only comes through the windshield vents on top of the dash board, the main vents on my dashboard don't blow any air, what could be the issue and how to test it? Thanks again guys for all those precious comments and shared experience.
You have a vacuum leak. When there is a vacuum leak, the "default" setting is automatically the defrost sitting. More than likely it is the vacuum canister under the hood that is leaking, or the vacuum switch behind the dash controls is bad. On the vacuum canister, put a bead of silicon around the nipple where it is attached to the metal can.
The only positions heat is allowed is below the OFF selection since the water valve is turned off in those selections and when full cold on the temperature control slide. The high heat setting provides vent and floor, low is just floor, fog is defrost and floor and ICE is just defrost. The system defaults to defrost with no vacuum so if it's not working as described, you likely have a vacuum leak.
Thanks again for your precious help, with those answers and diagram, I'll at least have a full heater by winter even if I don't get to refurbishing my AC by the end of summer hahaha
Jett At this time in your cars life you will need to reseal all the doors in the heater- a/c system .
