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A/C O-Ring Leakage

punchback on Tue July 05, 2011 9:06 PM User is offline

Year: 2000
Make: Ford
Model: Focus
Engine Size: 2.0 DOHC
Ambient Temp: NA
Pressure Low: NA
Pressure High: NA
Country of Origin: United States

I have a 2000 Focus ZTS with 133,000 miles. It's developed an AC leak that I'm having the darndest time getting corrected. After the 134a leaked out the first time I filled it with 134a and dye and found what looked to be a big leak at the connection to the condenser on the hose from the compressor. I bought an o-ring kit and initially just replaced the o-ring at that connection. I vacuumed the system and it held the vacuum for 15-20 minutes. Refilled with 134 and everything was COOL. Well... 3 days later everything had leaked out with another huge dye stain at the same connection.

After reading many posts about AC repair I took things apart again to have a close look at the connection. Since many suggested that the accumulator should be replaced when opening the system I did that. Replacing the accumulator necessitated replacing the hose from the accumulator to the compressor which is also the hose with the o-ring leak.

At the condenser there appeared to be something caked around the fitting where the o-ring seats so I cleaned it up and re-assembled, evacuated, filled with 134 and dye. Leaked out again! Same fitting!

I did notice that the new hose had a slightly different fitting than the old hose. On the new hose the aluminum block has a aluminum tube that protrudes beyond the block. On the new hose assembly the tube has a channel for the o-ring where the old assembly does not.

New Fitting

Old Fitting

Does anyone want to hazard a guess as to what going on? Can the condensor fitting be compromised??

TRB on Tue July 05, 2011 9:52 PM User is offlineView users profile

Image links do not work for me.


When considering your next auto A/C purchase, please consider the site that supports you:

punchback on Tue July 05, 2011 9:59 PM User is offline

Sorry just realised how to upload to forum.

New Fitting

Old Fitting

Notice the groove around the tube. The o-ring that came with the new hose assembly had the same as the original o-ring.

Edited: Tue July 05, 2011 at 10:04 PM by punchback

mk378 on Tue July 05, 2011 10:07 PM User is offline

These are so-called "peanut" fittings. Corrosion of the areas the o-ring touches (such as the tapered part of the hole in the condenser) will cause a leak.

punchback on Tue July 05, 2011 10:07 PM User is offline

On a fitting like this is the sealing surface the round raised area? Unfortunately I do not have a picture of the mating area on the condenser.

punchback on Tue July 05, 2011 10:09 PM User is offline

What is the best way to clean the condenser fitting? Will solvents works? If so which are best?

mk378 on Tue July 05, 2011 10:31 PM User is offline

If it's corroded you'll need to sand / scrape-- mechanically make it smooth again, being careful not to get debris in the line. If deeply pitted you would need to replace condenser.

punchback on Tue July 05, 2011 10:41 PM User is offline

I guess I'll be trying to get the condenser fitting as clean as possible. This will be the 3rd time I've filled the system. It's getting old throwing $20 out the window everything I fill and it leaks out. If it leaks out again I guess it's new condenser time.

GM Tech on Tue July 05, 2011 11:26 PM User is offline

Looks to me like sealing washers are used on these fittings, not o-rings---they seal by compressing the rubber, not by id/od of an o-ring....find the right sealing washer and be done with it...

The number one A/C diagnostic tool there is- is to know how much refrigerant is in the system- this can only be done by recovering and weighing the refrigerant!!
Just a thought.... 65% of A/C failures in my 3200 car diagnostic database (GM vehicles) are due to loss of refrigerant due to a leak......

JJM on Tue July 05, 2011 11:38 PM User is offline

The peanut connectors which I believe Ford started using around the 2000 model year (congrats on being the first) were not the much of an improvement over the original spring locks... and they fail the same way too... corrosion on the female end. MK is correct on the fix, polish out until smooth or replace. Ford even had a TSB on it, though I can't recall the number, but it basically involves polishing out the female end:

That, and usually a thicker O-ring and you should be good to go.


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