no heat from front vents but from the vents on the windshield?
- Thread starter jc411
- Start date
dave6666
Enthusiast
The only settings that allow hot air to circulate are "heat" and "defrost." I do not believe a properly functioning system allows hot air to the dash vents in a Viper.
REDSLED
Enthusiast
How many Viper have you owned that didn't have working A/C?
jcaspar1
Enthusiast
I can tell you why mine didn't for about a year. Because I didn't realize that 3$ worth of o-rings and 25 minutes of my time would fix it. Works great now...
LPDesRoche
Viper Owner
Kind of curious about that myself. I need to investigate my AC as well. I never use it, but I would like it to actually work if I had to use it for some reason.
dave6666
Enthusiast
More than likely the o-rings at the hose connections where there is a bolted flange. The compressor is one spot I think. Maybe the dryer too.
DaytonaViper
Viper Owner
My problem was at the compressor(96 GTS). Tight space to work in, but wasn't hard.
REDSLED
Enthusiast
I thought that heat did not come from the same A/C vents but only at the frnt window vents or from the whole on the lower portion of the dash?
jcaspar1
Enthusiast
I was planning on doing an illustrated upgrade on this but my photos came out too lousy. Basically, I charged the system with refrigerant with dye and found that after a week the system had lost pressure. Found that there was a leak in one of the lines going to the compressor (not sure which one). The area is easily accessable from under the car. I removed each of the lines (single bolt on each and removed the black o-ring on each line. Looks like this with o-ring removed:
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I replaced them with o-rings from a pack I got at Autozone. Pack has enough to do this repair 3 times. Be sure and keep the line tips clean when replacing:
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Here are the two I used 13.8x2.5, 13.7x1.9:
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Recharged system and has been good for 6 months so far.
Still don't have heat from my top vents....
eucharistos
Enthusiast
thanks for the nice write-up
.....maybe the other o rings in that pack are for the top vent heat 
.....maybe the other o rings in that pack are for the top vent heat I was planning on doing an illustrated upgrade on this but my photos came out too lousy. Basically, I charged the system with refrigerant with dye and found that after a week the system had lost pressure. Found that there was a leak in one of the lines going to the compressor (not sure which one). The area is easily accessable from under the car. I removed each of the lines (single bolt on each and removed the black o-ring on each line. Looks like this with o-ring removed:
You must be registered for see images
I replaced them with o-rings from a pack I got at Autozone. Pack has enough to do this repair 3 times. Be sure and keep the line tips clean when replacing:
You must be registered for see images
Here are the two I used 13.8x2.5, 13.7x1.9:
You must be registered for see images
Recharged system and has been good for 6 months so far.
Still don't have heat from my top vents....
thanks
im going to give that a try
dave6666
Enthusiast
Um. What's crappy about those pics?
Tom F&L GoR
Enthusiast
As a rule of thumb, when an AC system leaks and fails, it is most likely the o-rings at the compressor. (A salvage yard mechanic told me this since they resurrect old cars for resale.) I never thought about it until I replaced mine, but the back of the compressor gets HOT HOT HOT not just from the engine, but from doing the work of compressing. Touch it sometime. The o-rings get hard and then leak... duh.
I posted that I repaired my system without sucking out the "air" and that I simply charged the system. (How's the air get in there anyway, isn't it R-132a at atmospheric pressure?) I calculated that even if the system had air in it, the pounds of air vs. pounds of refrigerant ratio was very small. Same for pounds of water in the system. I wanted to first see if my repair worked at all and wasn't going to wait and spend more to find out I had to fix something else. Needless to say the AC purists thought it this was all a bad idea, including not using dual gauges etc, etc. However, I used the cheap store recharge kit and the AC has worked fine ever since.
I posted that I repaired my system without sucking out the "air" and that I simply charged the system. (How's the air get in there anyway, isn't it R-132a at atmospheric pressure?) I calculated that even if the system had air in it, the pounds of air vs. pounds of refrigerant ratio was very small. Same for pounds of water in the system. I wanted to first see if my repair worked at all and wasn't going to wait and spend more to find out I had to fix something else. Needless to say the AC purists thought it this was all a bad idea, including not using dual gauges etc, etc. However, I used the cheap store recharge kit and the AC has worked fine ever since.
Nothing - it's the upgrade procedure ones that he didn't post
jcaspar1
Enthusiast
That's it. Couldn't get my cheap point and shoot to focus on the compressor from under the car and get the flash to illuninate it. Also, didn't take as many as I would have it I had known it would work...
checked my o-rings on my compressor, underneath it the AC lines with the conduit on them were full of green dye that I had put in the system before.
the o rings didnt look cracked as far as i can see but they did look a little flat and worn out.
hopefully when i replace them my AC will continue to work!
thanks again
the o rings didnt look cracked as far as i can see but they did look a little flat and worn out.
hopefully when i replace them my AC will continue to work!
thanks again
Last edited:
jcaspar1
Enthusiast
My o-rings looked fine too without any cracks. Good luck.
dave6666
Enthusiast
If orings look fine - hence no corrosion - then the property that has caused failure is compression set. Any good elastomer has to have good compression set figures - the ability to spring back to it's original dimension - but time and heat will destroy even the best. At that point they are just no longer pushing back against the compressive forces in the oring groove, which is what causes the seal when all is good.
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