73 eldo ac compressor changeout w picture

[kkkaiser]

HI,  been a while, 73 has been going ok. 
I decided to replace the compressor. I had replaced the bearing several years ago, and it wont hold charge.

I bought an replacement.  it fit fine,, however, the rear of the unit has a different look.  The old one has this large nipple, see photo where red straw is pointed.  there was nothing attached to it.
the new one doesnt have a place to put that, just a opening with a little white plastic tab over it, (looks removable)

The old unit also had an attachment with a small pin on it, near bottom, See photo circled in black.

the new one doesnt have either the attachment location for the large valve or nipple or the small one. 

would these be because the new one doesn't have the traditional clutch that you can see engage, more of an enclosed type unit. 

any input on if their are connections the need to be made or included would be appreciated.  I have the car sold an part of the deal was to have this put on.   

["Cadillac Kid" Greg Surfas 15364]

The "circled" device on your old compressor is the super-heat switch sensor. It is wired into the compressor control circuit to disengage the compressor if the super-heat rises too high which indicates a severe shortage of refrigerant. It is intended to keep the compressor from destroying itself. It is POSSIBLE  that what appears to be a bolt with a white head on the new compressor is intended for the super-heat switch or the high pressure relief valve that is also on the old compressor but not apparent on the new one.
Greg Surfas

[benji808]

Is this an old air products compressor? If so, call them and they can talk through it. If I remember correctly on my car their VIR replacement had a pressure switch so the superheat switch was redundant and could be bypassed/ignored as long as I replaced the VIR. Alternately, I think they do make a superheat version if you want to swap it out.

["Cadillac Kid" Greg Surfas 15364]

Benjamin
The pressure switch and the super-heat switch are not the same. If the compressor is running a bit short of gas it probably will never cycle on a pressure switch (under load of course). It will however super-heat the compressed refrigerant to the point of endangering the compressor.
Greg Surfas

[kkkaiser]

how about the part that is pointed out by the red straw,  what is or was that, it was screwed in, and there is no correstponding point on the new one for it,

["Cadillac Kid" Greg Surfas 15364]

The red straw in the picture of the old compressor is pointing to the high pressure relief (safety) valve
Greg Surfas

[kkkaiser]

here are the specs on the unit,, it says about 3/4 down, it says superheat switch included.  does that mean its built in??

[The Tassie Devil(le)]

The Superheat switch is the one you circled in black.

Bruce.

["Cadillac Kid" Greg Surfas 15364]

If there is an electrical connection in the rear of the new compressor that would be it. If not the switch is NOT included. I don't see anything regarding the high pressure relief.
Greg Surfas

[kkkaiser]

ok,, out of sheer confusion, I thought id call old air, as they sell four seasons units.  I got this from rock auto, but they dont have any customer service to speak of.  Anyway, the guy was nice enough to help me some, but said I should call four seasons,, I did, I gave hime the new unit Serial number, he looked it up,  the part on the new one is for the pressure outlet.

on the new one, under where the the two large hoses  are, is a plug,  pretty non descript looking plug.  well, he said I have to go tot he old unit, pull out the old high temp sensor by way of pulling out a c clip, remove plug by way of a c clip on the new one, and put it in there.   now see, why would nt they give us some directions there?   would have save me four phone calls, wasting peoples time on this forum.. 

he also said just leave the white tab there.,, so, I guess problems solved and for anyone else who runs into it.

thanks to those who helped me get some definitions and solutions...

[MeToo]

It looks like I have the same issue on my new one for my '76. The issue I have with transferring the superheat switch from old to new is that mine might be faulty, since it failed to stop the compressor destroying itself when refrigerant leaked out.(the leak source appears to be the compressor seals)

Am I better to just get a superheat switch and install that on the new one?

Another question I had relates to compressor oil, if my compressor leaked oil, then surely using the amount of oil drained from the old compressor as a guide for how much to put in the new one would not work?

[Pghcc2006]

Anybody know what compressor to buy so we don't have these issues? I'm looking to replace mine in the spring.  1976 Fleetwood of it narrows it down.

I was thinking of either this one:

https://www.oldairproducts.com/product/21-2215-10-compressor?gfid=p117738-c124623


Or this one: https://www.originalair.com/a6-gm-5-single-groove-compressor

["Cadillac Kid" Greg Surfas 15364]

If you re-install an actual A-6 compressor you will not have any of the modifications or "work-arounds", but a good rebuilt seems to be getting harder to find. Glad I do my own.
Greg Surfas