Hdmike444

Hi all
wondering if anyone has some Info on diagnosing an ac system. Any ideas on how to detect leaks? I saw something about using r34 but Iam sticking to r 12
if anyone has has any help that would be great
thx

sorry I just realized I posted this in the wrong section

Allan R

Do you have a 72 Oldsmobile CSM Chassis Service Manual? It has detailed schematics, pictures and descriptions of servicing, troubleshooting and rebuilding.

Hdmike444

Ordered it but don’t have it yet
thx

Hdmike444

Ok so I have determined I need some ac parts, my compressor bearings are toast and probably the source of the leak. Should I buy a new one or have it rebuilt? Also where can I get a seal kit? And I have a fuse? That is gone because the unit ran out of Freon. The three prong in-line one at the compressor, any ideas on where to find that?
Thx in advance
mike

classicmuscle442

Check Rock Auto.

Dave26

I found the thermo limiter fuse at NAPA

RetroRanger

I recall a thread recommending a modern replacement for the compressor that was lighter and more effiecient, that might require r134 tho.

troyd

Having been through this.....

If all of your a/c bits and pieces are original, after the compressor....I'd be concerned about what's behind door #2. 50 year old hoses, condenser and evaporator......gotta wonder if they will hold pressure (and if it does hold pressure, how long will it hold pressure)

To convert or not to convert......r12 is out there and it's not as astronomically expensive as it used to be. IF, and this is a big IF, the only issue you have is a bad compressor......if you rebuild yours, get a rebuilt A6 or even go with a new one like the Pro6Ten....then I'd probably stick with r12.

However, IMO (and your mileage may vary)....if functioning AC is important (and to a fat guy like me, it is) The MAW factor comes into play. If you are already looking at a new compressor, a new drier is in order.....I'd probably, at a minimum, change out the hoses just because 50 year old hoses scare me. Now if you are in for a new compressor, drier and hoses....geeze, I'd probably think about a new condenser (which if you convert to 134 is a must). If you are in that far, a new evaporator and you darn near have an all new system. In which case, I'd probably just replace the POA valve with a cycling switch (or have the POA adjusted) and go with r134.

Anywho, that's what I did. Replaced everything and converted to 134 and I've got bitchin cold air on a hot day. Well worth it, IMO.

Long story short, I think the compressor is probably just the starting point....

Again, YMMV.

Cheers,

Troy

Hdmike444

Has anyone used the newer style aluminum compressor? I am going to start with replacement of the compressor and really wonder if it’s that much better.
thx

troyd

Yes, I’ve got the Pro6ten....no issues at all.

Cheers,

Troy

Hdmike444

Are you using r12 or 134?

troyd

I'm using r134. You can also order it with the oil for r12.......or at least you could a couple years ago.

Again, before throwing expensive parts at this......I would try and isolate the problem first. I wouldn't change compressors just for the sake of it without knowing it's actually the problem.

Cheers,

Troy

Hdmike444

I know the clutch is bad and it feels like there is play in the pulley to shaft so I’m assuming the pump is bad. I’m not sure how else to rule out the leak until I start there. Has anyone ever used the dye in a system to check for leaks. I know with the 134 you can but not sure about the r12

classicmuscle442

You can buy the clutch separate and yes R12 had dytell in it for leak detection. Use to buy 30# jug of R12 with dytell in it.

Hdmike444

Update
i added due to the system and haven’t found a leak and so I addedr12. It seems to be holding pressure but I think the compressor is shot because it’s not getting cold. It did when I added the Freon then stopped. I’m assuming the compressor is shot, any thoughts?

matt69olds

If the compressor is for sure junk, replace it and all the O-rings. Assuming you have gauges, I’m pretty sure you can rent a A/C vacuum pump from the auto parts stores, maybe a rental place, or last option, I have seen vacuum pumps that run on compressed air fairly cheap at harbor freight. Vacuum the system, hopefully you can get it to about 27-28 inches of vacuum (absolute minimum vacuum depends a lot on altitude). Close the valves on your gauges, if all is good it will maintain that vacuum for a while. If so, you can be reasonably sure the system is leak free. Recharge with the proper amount of refrigerant, make sure you add dye. If there is a leak, you can isolate the leak with a black light.

Hdmike444

I already added dye and found no leaks and it seems to be holding pressure so I’m assuming my compressor is shot. It does not sound good at all it is loud. I’m going to order a new one and see where I wind up

Charlie Jones

Forget about dyes etc.
Get an electronic leak detector . They aren't that expensive ;
https://www.ebay.com/sch/i.html?_fro...963+oldsmobile

Freon is heavier than air , so check the bottom and under components and hoses .
Make sure the air is calm , breezy conditions make it harder to find leaks .

Vintage Chief

I suggest if you're replacing the compressor, you take the opportunity to replace the receiver-drier while you have the system open. Fact is, you may have a faulty receiver-drier as well. You generally won't see leaks if it's clogged. None-the-less, I'd replace it while the system is open.

Hdmike444

Will do, it’s fairly inexpensive anyways. I think I am going with the aluminum compressor also, it’s only $90 more. It’s only money right?��

Hdmike444

So I’m getting into this now, I bought an a6 compressor, drier and new expansion valve. The line from under the valve snapped so I need a new one so I’m thinking I’ll replace all of them but all the sets I see don’t look like mine, specifically the one with the muffler bolted to the compressor, should I leave this one, anyone have a sources for line I’ve been searching with no luck.
thx

Hdmike444

this is the set
https://www.oldairproducts.com/produ...122513-c152948

has anyone used this set?

Hdmike444

Also has anyone used the aluminum a6 compressor from rock auto?
i bought the set with it and the dryer and valve but the back is not quite same. It looks like it will work but factory compressor has a spot for a wire press on connector and the new one doesn’t, I’mnot sure what it’s for

Hdmike444

So I found that it is the super heat switch, does the new compressor not need this? I’ve read that some people bypass this anyway

Hdmike444

Anyone? Bueller?

cdrod

The Superheat switch is a failsafe that will short the compressor clutch circuit to ground and blow the thermal limiter if the system pressure gets too high. This is a "crowbar" type protection method to shut down the compressor before it blows up. You can purchase a receiver/drier with an extra port for a pressure switch (called a trinary or binary switch) this can be used to protect the compressor without blowing the fuse. You'll need to rewire the compressor clutch through this pressure switch and you will no longer need the thermal limiter as this will protect the compressor from both a high pressure condition and an low pressure condition.

Hdmike444

So I just heard back from four seasons and they said I can use my original switch and install in in the new compressor where the blank is. This will make things easier.

droptopron

If you want to deal with AC experts, try these guys. They specialize in classic car heating & cooling. They do mail order too

https://www.caparadiator.com/