recharging a/c

**Darth Menace** · 06-16-2016

hey, I have a 98 GTS and the a/c did work when I got it, but alas no more. I bought one of those air operated vacuum pumps, and a recharge kit with gauge. Thought I would try it myself. Does anyone know of a good write up or have any guidance? I would love to get this operating, if even for the season

**Bugman Jeff** · 06-17-2016

Youtube is full of how-tos, there's not much to it. I will add though that I've recharged many, many cars over the years and I always use vent temp as an indicator of when I'm done, rather than what the gauges say. With the windows closed, and AC on full, I charge until I get a consistent 38°F-40°F out of the vent. You don't want the evaporator to get below freezing, if it does it can ice up blocking airflow through the fins.

**My98RT10** · 06-17-2016

Originally Posted by Darth Menace

hey, I have a 98 GTS and the a/c did work when I got it, but alas no more. I bought one of those air operated vacuum pumps, and a recharge kit with gauge. Thought I would try it myself. Does anyone know of a good write up or have any guidance? I would love to get this operating, if even for the season

Not knowing when you got your GTS but there might be an issue with leaking O-rings or Schrader valves (or other components) so that a refill will not sustain very long. Maybe you want to check for leaks first...

**Steve-Indy** · 06-17-2016

Have done a bunch of the quick fixes...on our older Vipers, many club members Vipers, and (seemingly) every 97-98 Blazer in our neighborhood. First, see if compressor runs...if so, does it click on then off then on every 4-5 seconds? If if works, try to fill with refrigerant (containing dye)...watching pressures on gauge AND, watch to see if compressor starts to run longer and longer. If this happens you are on the way to cool air. If you achieve this, shut it off and check both Schrader valves scientifically...you know, spit on your finger and rub a gob over it just like on a bicycle. If it bubbles, tighten it. Now, see how long it takes before charge depleted. If rapidly, "O" rings are next...starting with the ones at compressor...then on to the easy ones.

Believe me, this is not a high quality approach (it makes REAL mechanics shudder) but it worked for several seasons in several Vipers...before I threw in the towel and ask Yom Sessions to do it PROPERLY. If you want more amateur advice, call me. 317-402-9013.

**Darth Menace** · 06-17-2016

Originally Posted by Steve-Indy

Have done a bunch of the quick fixes...on our older Vipers, many club members Vipers, and (seemingly) every 97-98 Blazer in our neighborhood. First, see if compressor runs...if so, does it click on then off then on every 4-5 seconds? If if works, try to fill with refrigerant (containing dye)...watching pressures on gauge AND, watch to see if compressor starts to run longer and longer. If this happens you are on the way to cool air. If you achieve this, shut it off and check both Schrader valves scientifically...you know, spit on your finger and rub a gob over it just like on a bicycle. If it bubbles, tighten it. Now, see how long it takes before charge depleted. If rapidly, "O" rings are next...starting with the ones at compressor...then on to the easy ones.

Believe me, this is not a high quality approach (it makes REAL mechanics shudder) but it worked for several seasons in several Vipers...before I threw in the towel and ask Yom Sessions to do it PROPERLY. If you want more amateur advice, call me. 317-402-9013.

Thanks for your info. Seems like I will take a dab at it, but why was I told to buy the vacuum pump on the VOA facebook page? Like where does this come into play?

How do I make the compressor run? Like turning the a/c knob on and it should turn on?

Also, what are shrader valves?

Told you I am green at this

**SnakeWatching** · 07-24-2016

Originally Posted by Steve-Indy

Have done a bunch of the quick fixes...on our older Vipers, many club members Vipers, and (seemingly) every 97-98 Blazer in our neighborhood. First, see if compressor runs...if so, does it click on then off then on every 4-5 seconds? If if works, try to fill with refrigerant (containing dye)...watching pressures on gauge AND, watch to see if compressor starts to run longer and longer. If this happens you are on the way to cool air. If you achieve this, shut it off and check both Schrader valves scientifically...you know, spit on your finger and rub a gob over it just like on a bicycle. If it bubbles, tighten it. Now, see how long it takes before charge depleted. If rapidly, "O" rings are next...starting with the ones at compressor...then on to the easy ones.

Believe me, this is not a high quality approach (it makes REAL mechanics shudder) but it worked for several seasons in several Vipers...before I threw in the towel and ask Yom Sessions to do it PROPERLY. If you want more amateur advice, call me. 317-402-9013.

I just added half a can of A/C Pro to 1997 GTS (AC did work before but not that cool, 65 temp from dash vent with 90 outside today before fill). pressure did improve on gauge, but I did a check of Schrader valve and I did get a little bubble or two by the valve. Now seems like no one carries a good tool to tighten valve in any of the auto parts stores.

Steve (or anyone) is there a tool brand/part number to recommend! (IE which size valve is it?). Seems like some of the tools for sale are junk.

**Steve-Indy** · 06-17-2016

Suggest you call me when you are by car...tomorrow or another day. What you see above is about as much typing as one gets from me.

**Darth Menace** · 06-17-2016

Originally Posted by Steve-Indy

Suggest you call me when you are by car...tomorrow or another day. What you see above is about as much typing as one gets from me.

Thanks, I will do. I am MST so I will be sure to call at a time that is normal for both of us

**Drlee50** · 06-17-2016

When you turn on the a.c. with interior switch, it sends a request to the pressure switch on top of the dryer. If the pressure is too low or too high, it will not send signal to the compressor to turn on. If you have such a leak that there is no pressure you will need to jumper the two wires at the pressure switch to get the compressor to start and get pressure built up to the use the switch properly . you want to start off the adventure with that vac pump and draw out all the moisture out of the system . let it pull down for at least an hour. Also, when you do this with the manifold you can close the system under vacuum and eval for leaks prior to adding Freon. If it won't hold 29" of vac, it won't hold pressure either.

**Bugman Jeff** · 06-18-2016

If the system is low on freon but still has positive pressure in it, you don't need the vacuum pump. If the gauge reads zero and the system is empty of freon, it's now full of air. Air contains moisture, and moisture does bad things inside AC systems. The vacuum pump will put the system under vacuum to boil any moisture out of it(as pressure drops, so does the boiling point of water, down to where it will boil at room temperature). Checking to see if it will hold vacuum is a secondary benefit and can save you some freon because you'll be able to see if it leaks rapidly. If it is empty, how long to vacuum to get all the moisture out is very variable. I usually leave the vacuum pump running 30-60 minutes depending on the size/flow of the air compressor I'm using.

**Steve-Indy** · 06-18-2016

By the way, it system is empty, you will need a new dryer canister.

**Geronimo** · 06-18-2016

For you guys who want to get the air another 3 or 4 degrees cooler at the vent put some power curve in it from powercurve.net.

**drewsss** · 06-20-2016

Originally Posted by Geronimo

For you guys who want to get the air another 3 or 4 degrees cooler at the vent put some power curve in it from powercurve.net.

Thanks for the advice. Seems pricey though, for another 3-4 degrees...

http://shop.powercurve.net/11-Power-...-Unit-xxxx.htm

**Bugman Jeff** · 06-20-2016

Originally Posted by drewsss

Thanks for the advice. Seems pricey though, for another 3-4 degrees...

http://shop.powercurve.net/11-Power-...-Unit-xxxx.htm

Especially considering that usually just adding more freon while charging will get you another 3-4 degrees, and depending on your temp at the vent, you could already be very close to freezing at the evaporator. Any AC system can get the evaporator below freezing with the right amount of freon, although many new cars have sensors and are smart enough to shut the AC off if the evaporator gets too cold.

**Geronimo** · 07-02-2016

Originally Posted by drewsss

Thanks for the advice. Seems pricey though, for another 3-4 degrees...

http://shop.powercurve.net/11-Power-...-Unit-xxxx.htm

Yeah I know but it's a Viper. It's also a metal conditioner so the compressor with work less hard and last longer, so they say...

**Steve-Indy** · 06-19-2016

Darth Menace...did you get it working??

**Darth Menace** · 06-20-2016

Originally Posted by Steve-Indy

Darth Menace...did you get it working??

No I did not. I got sidetracked with the weekend, father's day and a car show. I am on days off starting tomorrow so I will give you a call. I try to work on my cars when the kids are in school and spend time with them when I am home

- - - Updated - - -

Originally Posted by Bugman Jeff

If the system is low on freon but still has positive pressure in it, you don't need the vacuum pump. If the gauge reads zero and the system is empty of freon, it's now full of air. Air contains moisture, and moisture does bad things inside AC systems. The vacuum pump will put the system under vacuum to boil any moisture out of it(as pressure drops, so does the boiling point of water, down to where it will boil at room temperature). Checking to see if it will hold vacuum is a secondary benefit and can save you some freon because you'll be able to see if it leaks rapidly. If it is empty, how long to vacuum to get all the moisture out is very variable. I usually leave the vacuum pump running 30-60 minutes depending on the size/flow of the air compressor I'm using.

Where does this vacuum hook up? I bought it because I was told to, but otherwise have no freaking clue

**Bugman Jeff** · 06-21-2016

Originally Posted by Darth Menace

Where does this vacuum hook up? I bought it because I was told to, but otherwise have no freaking clue

It connects to the gauge set on the same port that the can of freon will get hooked up to.

**Steve-Indy** · 06-20-2016

When attacking this situation, there are several simple steps to cover before you jump in to professional work.. I would suggest you try a BandAid or two first...then, you can always do it properly later. There is no reason to try to talk you into complexity just yet.

**Darth Menace** · 06-20-2016

I always like easy

Will get to it tomorrow. Things just got backed up

**Steve-Indy** · 07-02-2016

Darth...what did you do?

**Silver GTS** · 07-06-2016

My 98 GTS was pretty week I used a bottle of A/C pro last summer and I am still nice and cool :dude3

**Darth Menace** · 07-06-2016

Sadly is has been pretty hot here, and I have chosen to drive the GTO convertible instead of the Viper. This is upsetting for sure, but I am melting in that thing. Even my kids don't like driving in it anymore because of this. Even if I can limp it along and make it tolerable I would be happy

**Darth Menace** · 07-06-2016

I feel horrible taking all these offers and not acting on them. Work has often been crazy, followed with family time. I am off on the weekend (for once) so I plan on tackling it then. What time (your time zone) are you free for a call?