Curious Leak from AC Compressor?

[lazabby]

I changed the oil a week or so ago. I keep cardboard under the engine to check for leaks and to use it to kneel on while working under the car. Yesterday I noticed some spots and thought I didn't tighten the oil plug enough so I slightly tightened it and rearranged the cardboard to the "clean side". This morning I noticed some spots but it wasn't under the oil plug. SO I checked it out this evening. I notice drops hanging on to pieces on the driver's side that were green in color. I thought it might be anti-freeze but as I traced it upward, it looks like it was originating from the underside of the AC compressor, toward the rear of the car. I checked the water hoses in the area and the overflow tank but they all look good. What could be leaking from the AC compressor? The R134 is gas and wouldn't come out as a fluid could it? I cleaned everything up so I'll see if it's still leaking in the morning.

[eight8toy]

Does your r134 have a bunch of green dye additive?
That might be showing you have a good ac leak but is your AC working still?

[David T]

Could be refrigerant oil. When refrigerant leaks out it carries some of the oil with it. Other common leaks in that area;
Oil pressure sender
Cam cover behind idler bearing "O" ring
Could also be anti-freeze.
Clean things up good and watch for where it first appears. Leaks tend to occur up and towards the front of the car.

[DMC-81]

It would appear that your front seal may be leaking on the AC compressor. You're right about the refrigerant being a gas (unless compressed), but the Ester/PAG lubricant is an oil. Is it also wet around the AC clutch area?

Clutch area:

http://dmctalk.org/attachment.php?attachmentid=54097&d=1508030160

Here is the (carbon) seal that normally leaks (the round part next to the compressor):

http://dmctalk.org/attachment.php?attachmentid=53776&d=1506900376
In this picture the new parts are shown on top, and the old parts below.

[lazabby]

A/C was working fine on Wednesday when I was driving around. The green stuff looked like it was starting at the top of the engine, dripping from the AC condenser not lower. It was definitely green so it isn't motor oil. I can't find any leaks with any water hoses in the area. I noticed a drop on the cardboard this morning on the way out so I'll have to take a look later and see where it's accumulating on the engine.

[lazabby]

The leak is definitely coming from the AC compressor. I had the AC serviced in March and there was a leak. It was filled with Red Tek and probably some kind of oil which is leaking. Is there a seal that can go bad allowing the leak? Here is a picture of the underside of the compressor.60296

[DMC-81]

The leak is definitely coming from the AC compressor. I had the AC serviced in March and there was a leak. It was filled with Red Tek and probably some kind of oil which is leaking. Is there a seal that can go bad allowing the leak? Here is a picture of the underside of the compressor.60296

Yes, it appears from your picture that the o-ring seal between the front head and the body is compromised. It is the black ring in this picture:

http://dmctalk.org/attachment.php?attachmentid=57561&d=1532897839

...unless the oil is dripping down from the front seal in my other post above ^ which is a more common failure.

[lazabby]

Yes, it appears from your picture that the o-ring seal between the front head and the body is compromised. It is the black ring in this picture:

http://dmctalk.org/attachment.php?attachmentid=57561&d=1532897839

...unless the oil is dripping down from the front seal in my other post above ^ which is a more common failure.

How does one fix this?

[DMC-81]

How does one fix this?

Hi Shannon. Well, most people just buy a new compressor but if you are adventurous and sufficiently skilled, the 2 seals can be replaced (and the bearing for good measure). The procedure is detailed here:

http://dmctalk.org/showthread.php?15632-Refurbing-a-Very-Early-A-C-System

..starting on post 14.

[WHO1DMC]

Hi Shannon. Well, most people just buy a new compressor but if you are adventurous and sufficiently skilled, the 2 seals can be replaced (and the bearing for good measure). The procedure is detailed here:

http://dmctalk.org/showthread.php?15632-Refurbing-a-Very-Early-A-C-System

..starting on post 14.

That's what I did is got a new compressor you can find them relatively cheap just have to exchange the backs and done.

Dave B.

[Bitsyncmaster]

I once had a compressor bolt fall out (not on a DeLorean). The result was a leak like your seeing. The threads were stripped but it had held many years with no problems. I guess the factory had messed it up or some vibration that made if fail. I did fix it using a helicoil.

[kings1527]

Unless you're looking to be real adventurous and have a bunch of time, I'd recommend just putting in a new compressor that's brand new from Sanden rather than NOS and it's also a direct drop in replacement. Same as the original. This is that compressor:

http://store.sanden.com/index.php/4708.html

I've had the same one in my car for about 5 years and it's been perfect. If you're using R12 like I am, simply drain out the PAG oil that is pre-filled at the factory and replace it with an equal amount of mineral oil. Fill the system with R12 and you're all set. If you're using r134a, even better. Just mount it, connect the hoses, and fill the system with refrigerant.

The 4708 model of the SD7H15 couldn't be a more perfect fit for the DeLorean, no matter which refrigerant you're using.

[SBL]

When all is correct, with stock compressor, using R134a, how many PSI should the low pressure read as you add the refrigerant? Will this vary based on the RPM or temp? I read somewhere that 35 PSI was acceptable.

[Bitsyncmaster]

When all is correct, with stock compressor, using R134a, how many PSI should the low pressure read as you add the refrigerant? Will this vary based on the RPM or temp? I read somewhere that 35 PSI was acceptable.

The low pressure is controlled by the low pressure switch. Basically you should see it swinging about 25 to 45 PSI as the low pressure switch cuts in and out. It is not affected byt the amount of charge of the system.

[SBL]

Thanks. That will be what I need, David.