W123 leaking expansion valve - PeachParts Mercedes-Benz Forum

stephenc1984 · #1 06-15-2018, 07:59 PM

I posted a few weeks back regarding this issue and hopefully some updated info will help me solve my leaky r12 system.
When the a/c is charged it puts out 38-40 degree air. Over a period of a half year or so, the charge leaks down. I put a red dye into the system to give a visual as to where it is leaking. I could not find any dye under the hood. Today I found what appears to be a red color on the insulation between the kick panel and the expansion valve. What do I have to do to safely replace o rings on the expansion valve? Any other info I would appreciate. I want to stay with r12 btw. Thanks in advance!
-Steve

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tangofox007 · #2 06-15-2018, 08:22 PM

Quote:

Originally Posted by stephenc1984

What do I have to do to safely replace o rings on the expansion valve?

I would try tightening the fittings first.

Quote:

Originally Posted by stephenc1984

I want to stay with r12 btw.

Yes, you do.

stephenc1984 · #3 06-16-2018, 11:47 AM

[QUOTE=tangofox007;3821807]I would try tightening the fittings first.

I would assume that the o rings are shot since it is leaking. But I can see if they are loose.

BillGrissom · #4 06-16-2018, 10:17 PM

I doubt they would loosen on their own. If you already lost the refrigerant, just unscrew and install new HBNR O-rings. Some from my HF kit fit. "just" wasn't easy. I had to use a long metric wrench (HF set) and secure the body w/ another long wrench. I replaced on my 1984 & 85, plus re-hosed the suction line in both, and changed all other O-rings.

If you still have refrigerant, the law requires you to have a certified shop recover it first. That said, when I was a teen one could buy a "BB machine gun" which used a can of R-12 (~$0.30 then) to shoot a stream of thousands of BB's. Then the O-zone Hole saga began, forcing the change to R-134A which is now being outlawed since a bad "climate change" gas. The EPA doesn't talk about the Ozone Hole today, other than "fixed it". Questionable, since most media stories of the time turned out to be wrong (deformed frogs in Costa Rica, ...). Let your conscience and understanding of science guide you, and beware of EPA drones watching.

stephenc1984 · #5 06-17-2018, 12:40 AM

Quote:

Originally Posted by BillGrissom

I doubt they would loosen on their own. If you already lost the refrigerant, just unscrew and install new HBNR O-rings. Some from my HF kit fit. "just" wasn't easy. I had to use a long metric wrench (HF set) and secure the body w/ another long wrench. I replaced on my 1984 & 85, plus re-hosed the suction line in both, and changed all other O-rings.

If you still have refrigerant, the law requires you to have a certified shop recover it first. That said, when I was a teen one could buy a "BB machine gun" which used a can of R-12 (~$0.30 then) to shoot a stream of thousands of BB's. Then the O-zone Hole saga began, forcing the change to R-134A which is now being outlawed since a bad "climate change" gas. The EPA doesn't talk about the Ozone Hole today, other than "fixed it". Questionable, since most media stories of the time turned out to be wrong (deformed frogs in Costa Rica, ...). Let your conscience and understanding of science guide you, and beware of EPA drones watching.

The larger nut on the south side of the expansion valve I was able to get 1/8-1/4 inch turn to tighten. The other three were hard as a rock and I could not budge either way. I'm not on board with all the politics regarding r12 and the EPA. My little 240d needs all the help it can get 90-100+ heat in the summer, 134 doesn't cut it. Even if the EPA is correct about r12, I feel I'm doing my part by running veggie oil I source from local Restraunts. I digress, I'm hoping the little turn I got out of it, will stop the leak.

ROLLGUY · #6 06-17-2018, 11:13 AM

It is best to use soap and water solution (or kids "bubbles" from the dollar store) if you still have pressure in the system. Even with UV dye, leaks are sometimes hard to find, but the bubbles will always show a leak.