A/C Exploded!

[ratdude747]

My A/C had a sudden leak. Long story short, the threaded connection between the accumulator and evaporator came loose or something and loudly vented.

Background:

I'm doing some A/C work to correct a slow leak today. I suspected faulty O-rings in the low pressure line's connection to the Accumulator; I redid the O-rings last fall and it never did seal correctly.

Anyway, I swapped accumulators, adding 6 oz of PAG 46 oil. I replaced all 4 O-rings while I was at it using spares from last fall. I put it all together and Vacuumed it out for a few minutes until I got it to -27mmHg, and let it set for 30 minutes. During that time the pressure rose to -20mmHG, But I charged it with 2 12oz cans of R134a in hopes of being able to use my sniffer to find the leak.

The AC worked great for the 15 minutes I ran it to see my pressures. I shut it off to do a sniffer test, and while I was powering up the sniffer HISS!!!! Very loud leak at the threaded connection between the accumulator and evaporator. Lots of dye/oil mix came out too.

I had the connection tight and all... Bad O-ring? Or is something else to blame?

I did notice that the accumulator and evaporator didn't want to line up straight... maybe that's related?

Suggestions?

 

[ratdude747]

Update:

O ring looked OK. Replaced it anyway. Tightened the connection more this time. Held vacuum better. Run charged it, still leaking bad when the pressure is above 40psi. Had to vent some off to prevent another explosion.

Could something with the evaporator be to blame? Or did 4 seasons give me a bad accumulator?

 

[ratdude747]

I think I found the problem.

I noticed some aluminum shavings in the Accumulator port. Looking at the old one, I saw the same thing

I began to wonder if I had the wrong O ring in there... did some reasearch, and found that this is a somewhat common issue:

http://www.ford-trucks.com/forums/1289122-a-c-system-o-rings.html#post13916581

Ok, maybe we're on to something!

I confirmed the issue by looking at this chart. Sure enough, I had a thin .07"ish O-ring in there this entire time, not the 0.10" one that the chart calls for. No wonder it always had a slow leak?

I've swapped the O-rings and doing a Vacuum test. If that checks out, this thread can be moved to a better sub-forum as it's no longer an emergency.

 

[Doofy]

How's your orifice tube, plugged? Did you overfill with PAG Oil? I just repaired the ac in the wife's Jeep and none of the 200 o-rings in my Super-Duper o-ring kit fit anything. I did buy new lines and they all came with new o-rings. I had to replace the condenser, drier and the orifice tube. Had to do some precise figuring on the proper amount of PAG OIL to use because I couldn't find any R134A without the damn oil, stop leak and dye. Even had to remove and drain the compressor to see how much oil it had. Too much oil or refrigerant can be a bad thing.

 

[ratdude747]

How's your orifice tube, plugged? Did you overfill with PAG Oil? I just repaired the ac in the wife's Jeep and none of the 200 o-rings in my Super-Duper o-ring kit fit anything. I did buy new lines and they all came with new o-rings. I had to replace the condenser, drier and the orifice tube. Had to do some precise figuring on the proper amount of PAG OIL to use because I couldn't find any R134A without the damn oil, stop leak and dye. Even had to remove and drain the compressor to see how much oil it had. Too much oil or refrigerant can be a bad thing.

All of the oil went into the accumulator. Last time I barely got any in; I had about 6oz in my bottle and the spec for the truck is 7oz. Most of it ends up in the accumulator anyway...

I replaced the orifice tube last time with a red variable one. I also did the lines going to the compressor as my hoses were chewed up. The condensor, evaporator, and compressor are AFAIK stock.

 

[Doofy]

Sure glad it was as simple as o-rings. Thanks for the update. O-Ring chart is great too!

 

[ratdude747]

Sure glad it was as simple as o-rings. Thanks for the update. O-Ring chart is great too!

Actually IDK... that O ring made it worse, I found one that matched the chart a lot closer, tried it, back to where I was. I didn't go super tight though, so I tightened it as far as I dare, and trying it again. In about 25 mins I'll have an answer.

 

[Doofy]

None of my 200 o-rings were thick enough to seal either. Good luck.

 

[Denisefwd93]

The accumulator is NOT for the oil although there will be some in it. the Accumulator is for the refrigerant and reduces the pulsation from the compressor The oil is miscible and moves through the system and most will be in the compressor. Hope you don't have double the oil required! Did you dump/remove the old oil?

 

[ratdude747]

The accumulator is NOT for the oil although there will be some in it. the Accumulator is for the refrigerant and reduces the pulsation from the compressor The oil is miscible and moves through the system and most will be in the compressor. Hope you don't have double the oil required! Did you dump/remove the old oil?

No I didn't. When the seal blew a lot of oil came out though. Also I barely got an ounce in last time and I'm sure I was running quite a bit low.

When I say accumulator, I'm referring to the low pressure one that doubles as a receiver drier. Not the smaller accumulator on the high side that's part of the compressor lines.

 

[Denisefwd93]

The small one is a muffler there is still oil in the comp if you didn't drain it. Too much oil in the high side can "dead head" and blow things apart because it becomes hydraulic pressure.

 

[ratdude747]

The small one is a muffler there is still oil in the comp if you didn't drain it. Too much oil in the high side can "dead head" and blow things apart because it becomes hydraulic pressure.

Well oops then...

---

Good news: I think I got it to seal finally. Went ahead and recharged it

Bad news: The compressor is making an intermittent noise not unlike an air compressor. Did I kill my compressor?

 

[Doofy]

If you have a a.c. manifold gauge set you should be able to see a super high pressure on the high side. To much oil could harm the compressor or prevent proper a.c. cooling.

 

[ratdude747]

If you have a a.c. manifold gauge set you should be able to see a super high pressure on the high side. To much oil could harm the compressor or prevent proper a.c. cooling.

Yes I was using a manifold gauge set. No, I don't recall seeing dangerous pressures on the high side.

 

[Denisefwd93]

If you have a a.c. manifold gauge set you should be able to see a super high pressure on the high side. To much oil could harm the compressor or prevent proper a.c. cooling.

Yes I was using a manifold gauge set. No, I don't recall seeing dangerous pressures on the high side.

This is a big misconception about the high side. and the person charging more more into the lo side can easily put in 3-4 times the actual charge needed. A high side blockage will not usually show a high gauge pressure because the gas will condense into liquid and give up heat. unlike when a fan is not moving the air across the condenser. Finally when it's all liquid back to the comp and it becomes hydraulic pressure. it's usually too late and the comp valves get damage, joints can blow apart etc.


all this is why I always say "know what you have or don't have before you add or think you need more." (oil or refrigerant)