Guys, some of you know my car, '70 351c, but its a driver, we drive it a lot and summer is creepin in. My fiance drives it, and the AC just aint cuttin it. What little I do know about the system is it has a brand new dryer and some new hoses. The air is barely even cooler than ambient, the compressor when running sounds like a can of rocks and there is lil residue around one of the hoses, so I think the compressor needs to go.
Im really really green with HVAC knowledge so I dont even know if its been converted. Trying to get it back up cold on the cheap. I know it needs a compressor so I was looking to convert it to a sanden type because its easier on the engine especially idling, and quieter. Will this alone get me cold air? How can I tell whats in the system? Sorry, I know its a loaded question, without a lot of detail, not sure where to begin…I guess I can take it to a shop but thats usually against my religion
Also, my passenger side AC vacuume canister is leaking, im in need of one if someone has one willing to sell.
After replacing the compressor you’ll need to recharge the system anyway. Depending on the fittings your car has, it may be an easy conversion to R-134. My car, for example, doesn’t have fittings for the R-134 system so my fittings would have to be changed to recharge and convert it. This is one of those situations where it may make sense to at least have a shop look at it and tell you what they’d need to do to convert.
Not to go all EPA on you, but if you have R-12 in there, you really don’t have a choice but to visit a competent shop - at least to evacuate the system. Mother nature does not want you to vent that to the atmosphere. I’d get a leak test too, before investing in a new compressor, as the job gets a lot more complicated if (for example) you need to change the under-dash components.
I’m not an expert on this, but I believe if you have R-12, then the service ports will have threaded-type fittings. R-134a has quick connects. You might also look for a service tag that should have been applied if previously converted to R-134a.
Ok…Looks like I need to fins a competent shop. I would evac that stuff in the air, I’d have a shop do it. I know that all the fitting look to be stock, threaded type. Not a push type. I searched for a tag, dont see one so…no telling whats really in there. I think I’ll start by taking it to a shop to investigate and at least release the gas so I can swap the compressor.
Once the sanden is on Im assuming a shop will need to replace the hoses and dryer and charge it? Also, without that canister my actuator dors are not working So I’ll need that soon as well.
Thanks guys, I NEVER go to any shops, hopefully I can find one that is not in a mood to bend me over.
If you want to stick with R12 you will want to replace the compressor, drier, and perhaps any of the hoses that appear to be giving up the ghost. The drawback with R12 is the cost. R12 can get quite pricey depending on were you source the gas. Typically retail on R12 is pushing $80.00 a lb. (Our AC systems in 69-70 system uses approx 1.88 lbs of R12). You could run R12 with a Sanden update if you wanted to. The newer rotary type of compressors are much more efficient and tend to much more reliable long term vs the old York or Tecumseh compressor used by Ford.
If you do decide to convert to R134A there are several things to consider.
The old oil and refrigerant in the system now is not compatible with R134A. This means any existing parts (condenser, evaporator etc) needs to be flushed and cleaned. This is usually best handled by removing the offending components from the vehicle and have them flushed with an AC flushing agent or something as simple as lacquer thinner. The reason I mention the lacquer thinner it is cheap and when it dries it leaves no residue. Since you are already changing the compressor out you will not have to worry about cleaning the compressor. If you go back with an original type of compressor you may have to fill it with oil depending on the vendor you use.
Your old Discharge hose (compressor to condenser in front of the radiator) should be made of rubber. If this is an old hose it will not have any modern barrier in it to prevent the R134A from accually bleeding right thru the hose. At the bare minimum this hose needs to be changed. The other 2 hoses originally were made of a hard nylon material and if they are in good shape they could be reused if you are on a tight budget. Just make sure they are blown out well with some compressed air to get as much of the old oil out of them. I do not recommend running any flush thru these hoses unless the flush states it is safe for rubber/nylon products.
The old condenser in front of the radiator is an older serpentine core w/ 3 circuits in the passes. This is fine when running R12 but with R134A this can be an issue in high heat/slow speed situations. What happens is the R134A operates at a higher pressure and this creates a higher heat load on the condenser. In real world driving conditions this can cause a “warm up” of the air coming from the vents at slow speed or at stop lights. The older condenser will not keep up with the additional heat load and this equates to warmer air temps at the vent in the car. When your moving 45+ mph this should be a non issue but if this car is used in traffic this can become a problem on a hot day. Here at Classic Auto Air we manufacture a direct replacement condenser for the 69-70 Mustangs that is done in the OE serpentine pattern but we did the extrusion w/ 6 circuits instead of the stock 3 which gives you much more metal surface area to help with the additional heat load the R134A generates. This is a several hundred dollar upgrade but it is well worth the money if you do need to change the condenser anyway or if you drive in extreme heat at slow speeds on a regular basis.
When charging R134A you should run approx 70-80% of the original charge which comes to 20-24 oz R134 in these 67-73 systems. This is also important as R134A is not as forgiving as R12 when it comes to charge level. Too much or Too little the system will not function properly. Make sure all your o-rings are replaced with R134A compatible o-rings and if you are sticking with the original type of compressor you will need R134A charge port adapters.
Many thanks Ron. Very good post. I appreciate it, gives me about everyhting Ive been pondering…Im really debating on how much I want to go with this, and I too was cusious if I needed to replace the condensor with the R134. i might just end up calling you, if you dont mind. Are all sanden compressors compatible with R12? If I we’re to stay with R12, keep the condensor, flush lines and use the sanden would he system work efficiantly? Ive heard the R12 is colder, is that a myth? and also…Im in the FortWorth area, would R12 even be available for me?
As far the Sanden compresor if you wish to run R12 make sure you specify to your preferred vendor you are going R12 so you get the compressor w/ the r12 ports on the back of the compressor. The R134A Sanden does not have the ports built into the compressor. they will be located on the hoses at the fitting connecting to the compressor.
R12 is not colder per say but in a system original designed to operate at R12 pressure levels it will work better. All your new vehicles run R134A and since the systems in these cars are designed for R134A they will blow ice cold. You can convert to R134A in our cars but you will need to set the system up to handle it.
I am not sure who in Ft. Worth would have R12 but my advice is to find an established AC shop with techs with gray hair As they may have experience with our type of AC system.
give me a call and I will be happy to go into more detail.
I just thought I’d metion Freeze 12. I used it when I repaired the leak in my system. I just didn’t want to make all of the changes for 134. I paid about $15 a can and it uses the same compressor oil as R12.
Steven
Found this company called “Old air products”. They are local and in my area, I called them up and it turns out they make nice retrofit kits. I talked a bit to a tech guy there and he pretty much said everything you did Dave. He recommended running their R134 Under hood performance kit. http://www.oldairproducts.com/catalog/brackets/50-0020/underhood-performance-kit-p-5173.html?Make=Mercury&Model=Cougar&Year=1970 This comes with dryer, condensor, hoses and pump specced for R134. And runs at 580.00. the kit withut the condensor runs at $340.00
I asked about running R12 and he said I could keep the existing condensor with R12, but the price of R12 makes it hard to justify. I didnt ask about Freeze 12 but probably should have. What about flushing the oil out of the exaporator if I run r134?
and there is lil residue around one of the hoses, so I think the compressor needs to go.
As they may have experience with our type of AC system.