A/C O-rings

DrumrBoy

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My A/C stays charged for a couple of months.....time to change the o-rings to see if that's where the refrigerant is leaking out.

I usually just start taking stuff apart and figure it out as I go:nono:, but with the A/C lines one wants to be ready to do the operation fast in order to prevent moisture absorption by the oil in the system.

So, I'm double checking (hopefully) with someone who's changed out the A/C o-rings before.

Below is a pic of what the manual says are the blocks for the inlet and outlet of the compressor. Looks like two blocks with one bolt each (but it might be one block with two bolts and two hoses).

Question for someone who's been there - Are these the only two bolts required to expose the o-rings, and are the o-rings part of the block that comes away from the compressor or are they in the compressor?

DSC_01262.JPG
 

Bexar80

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With the left front tire removed it is very easy to access and either pull the line into the wheel well or underneath the car (I don't remember off the top of my head). Just the one bolt holding each fitting on and the o-rings are on the lines.

DO NOT use the SAE size o-rings from the parts store, the o-rings are METRIC. The A/C system is built by Denso, a supplier to primarily Japanese car manufactures. I went down to my Toyota dealer and got the correct o-rings for the compressor and filter dryer. They simply match the sizes up, there are only about four distinct size choices so don't worry and I've done this several times on my Toyota trucks.

The o-rings in the compressor fittings harden due to the extremely close proximity to the exhaust. After servicing my system I am convinced of this which probably accounts for 95% of all Viper A/C system failures.
 
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PhoenixGTS

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When I had leaking o-rings it was the ones where the hard lines connected to the condensor out in front of the radiator. I replaced the ones on the compressor at the same time to be safe, but they were not the ones that leaked. Make sure and check for residue up front.
 

jcaspar1

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I used the ones in the pictures I took in this thread. They are metric 13.8x2.5 and 13.7x1.9 mm
Have been working great for the past 2 years despite our 105+deg summers.

Have enough left to do it 2-3 times more.....
 

Tom F&L GoR

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The o-rings in the compressor fittings harden due to the extremely close proximity to the exhaust. After servicing my system I am convinced of this which probably accounts for 95% of all Viper A/C system failures.

Don't do this - but if you ever touch an AC compressor while running you will find it is HOT. Proximity to the exhaust doesn't help, but the heat it generates anyway makes you wonder how it lasted as long as it did. I changed only the o-rings on the compressor in/out (on my '94 many years ago) and it was the problem, which has been fine for at least 4-5 years.) Good luck, hope you have small hands....
 
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DrumrBoy

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Thanks Euc. I did the search and found the first one (and several others) but this one must've been buried on page 7 or something. Actually had a pic of the area with the lines disconnected. Had I seen that one, I wouldn't have posted. Oh well, the pic I took with the the lines connected may help another first-timer. Its a 10mm wrench btw and the whole operation takes 15 mins.
 
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DrumrBoy

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hope you have small hands....

Yeah, it is a tight squeeze in there. I did it from underneath, I couldn't see how going through the wheel well would make it any easier.
 

Bird325

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Did mine yesterday after my AC just wouldn't handle the 110 degree days we've been seeing. Went in from the top as it seemed easier than from the bottom using a 10mm short socket and a U-joint ratchet. One ring had been replaced by a previous owner, but I did both since I had it apart. Not too bad, but it took about 30 minutes as it was the first time to do this. Be aware that if there is still freon in the lines, it's going to VENT when you break the seal ... cover your headers with a towel or you're going to get refrigerant oil on them. It'll smoke and maybe even catch fire when you start it up if you don't!

Filled the system with R134a using a gauge/fill kit from O'Reilly up to 44 PSI on the low side, compressor running. It's cooling well, but I still have foamy bubbles in the sight glass when running. In the old days, we would use those little cans of freon until the bubbles stopped, but I was afraid to put in any more. Does anyone know if the bubbles will minimize as the system settles in?
 

jk

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Well, you know you should not have bubbles which indicate low refrigerant pressure. Those built-in gauges on the cans of refrigerant will get you close - close enough to cool. If what you see is milky-white, you might have moisture in the system.
 

Red Snake

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Just replaced my o-rings. Man it's tight working in there. I found it easiest to get them from underneath the car. Took me about an hour total including the recharge. ;)
 

Bird325

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Even though it cools well enough, I'm going to do the full monte and get it right. A friend just told me last night that he will come over with his pump, gauges and Freon to fix it ... no charge! He's gear head and loves American Muscle. Wish I had known he had the setup before I did it the cheap way.
 

97GTS

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I had a persistent AC leak. Would stay charged for about a month then slowly leak out. Did the o-ring fix and I am going on 6 months with cold air. AND I am in Central Florida where the heat and humidity will kill a man during the summer.


Ron
 

DarcShadow

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In this thread and the other the sizes, 13.8mmx2.5mm & 13.7mmx1.9mm are called out. I'm assuming 13.8 goes on the larger hose and 13.7 on the smaller?
I swapped my o-rings tonight and the sizes of the ring I took off the larger hose seemed to match the 13.8x2.5, but the smaller hose was a closer match to 10.8mmx2.4mm. I've got a 2001 GTS, any chance mine is different from what was called out on here already? Or, the small one I took of was green and the other was black, has someone already replaced the ring before and put on the wrong size? Although the 10.8 did seem to fit better then the 13.7.
 

DarcShadow

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So I should probably go back and put the 13.7 on rather then the 10.8? I really don't want to take that stupid thing apart again. :( errrrr
 

Red Snake

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I would run it with the ones you just put on and check for leaks. If it doesn't leak, don't worry about it. ;)
 

Fatboy 18

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Ive got to look at this problem, the last time I had my air re-gassed they put a green die in it, I looked under the car on the weekend and there is green die all over the chassis below the AC compressor pump :(
 

Bird325

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Just had a Viper AC party in my garage this morning with DarcShadow and Ba$$fan ... three Gen II's in my driveway all needing AC help. O-rings replaced already on two of them, the third done here in the driveway. We pumped all three down and charged them up with a borrowed manifold and a keg of R134A. It was interesting that all three of them acted/responded differently to the new charge.

They are all cooling nicely, but the 2000 GTS was acting kind of funky on the low pressure side. Even though we couldn't hear or feel the compresson kicking in, the gage was showing the pressure going between 32 and 45 psi like the compressor was on/off/on continuously. We pulled the pressure switch and jumped it - same behavior. With it unplugged, the pressure climbed to the point where we shut it down (around 100 psi). With it plugged in, the cooling works OK, but the pressure is in a constant state of swinging back and forth.

Anybody have a clue as to why this might be happening? Darren can report back later on how it did on the trip home. I have to leave my window down or it gets too cold now. Thanks for convincing me to pump it out as it works MUCH better now.
 

ba$$fan

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They are all cooling nicely, but the 2000 GTS was acting kind of funky on the low pressure side. Even though we couldn't hear or feel the compresson kicking in, the gage was showing the pressure going between 32 and 45 psi like the compressor was on/off/on continuously. We pulled the pressure switch and jumped it - same behavior. With it unplugged, the pressure climbed to the point where we shut it down (around 100 psi). With it plugged in, the cooling works OK, but the pressure is in a constant state of swinging back and forth.

Anybody have a clue as to why this might be happening? Darren can report back later on how it did on the trip home..

AC blew cold on the drive home yesterday and after a drive this morning. I do seem to hear a hissing or sighing from the vents frequently, thinking that might be the result of the compressor turning on and off constantly?
 

VIPER PIT

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It could be too much refrigerant. That tends to send pressures all over the map. The system once vacuumed down only takes 30 ounces of refrigerant. Once recharged with the proper refrigerant the sight glass will be clear.
 

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