Help Recharging theAir Conditioning System

[SYNFULL]

When I had mine checked at a friends shop, he vacuumed the system and then refilled it. However when we got to the recommended charge pressure there were still bubbles streaming in the sight glass and he was afraid to put in anymore.

I don't mean to come across poo-poo-ing the folks recommending a visit to a qualified technician with proper gauges, but there is a procedure in chapter 24 of the Dodge service manual and explicit suction side pressures depending on ambient temperatures. The low pressure cutoff switch is also the high pressure switch, so there is a high side protection system also. The Gen 1 capacity is 30 oz, so don't add more than three cans!

The suction side pressure is what the gauge is reading. In "Adding Partial Refrigerant Charge" it says to jump the pressure cut-off switch (to force the compressor on if there is not enough r-134a in the system), charge until the sight glass is clear and then add 8 oz additional refrigerant. How many people like me used to stop when the bubbles were gone?

You always have the triple check (after the bubbles) of what the pressure gauge says and what the air temp at the center outlet is.

If there is a little pressure (push the schrader valve pin) then air cannot have gotten into the system.

I'm with Aaron - if it works reliably at only 95% efficiency, that's a lot better than not running.

 

[Tom F&L GoR]

Well, if it's cold, it's good. It works, right?

Otherwise, after vacuuming, you can add to the maximum charge weight rather than pressure. The system can't make excess pressure with less than full charge?

 

[got one]

Dave, I am thinking about my system as well, I will be curious how yours turns out...along with your address and a convenient time to bring my car over

 

[dave6666]

Dave, I am thinking about my system as well, I will be curious how yours turns out...along with your address and a convenient time to bring my car over

I'll bring my new - and soon to be tested - gauge set along tomorrow if you like...

Charging it this morning after a few more cups of coffee.

 

[menglert3]

What you really need to do to get it right is clean out the system, you can get the spray bomb cleaner and with compressed air, disassemble, clean and dry. Put in all new O-rings, tighten, replace dryer, put in an inline filter then pull vac. to 30 HG for as long as you can I did for 48 hours. When satisfied jumper wire to make AC Comp. run and start dumping in your R134A.

 

[dave6666]

What you really need to do to get it right is clean out the system, you can get the spray bomb cleaner and with compressed air, disassemble, clean and dry. Put in all new O-rings, tighten, replace dryer, put in an inline filter then pull vac. to 30 HG for as long as you can I did for 48 hours. When satisfied jumper wire to make AC Comp. run and start dumping in your R134A.

Although I did run into some issues with my manifold hoses (don't ask...), with about 90psi of static pressure still from the 134a in the system, why would I be concerned about moisture and dirt in the system?

 

[Iceman]

Does any vendor sell a kit to replace all the AC O-Rings on the Viper? Should be a lot easier than going to PepBoys to match the current O-Rings.

 

[Tom F&L GoR]

Actually you want to go to Pep Boys because they will sell you an assortment box with 5 different sizes, multiples of each, for less than $10. Dodge will charge you more than that for 1 o-ring.

 

[sirhc76]

HaHa

Bought a manifold and hose set today to check the pressure and possibly add some r134, well the yellow hose has no adapter for the can. Now we are off to find the answer to my new problem. Shade tree mechanic-ing at its finest on this thread BTW. Now all I need to know is what the readings should be when running a static test with the car off and on. Time to start digging.

Chris

 

[dave6666]

HaHa

Bought a manifold and hose set today to check the pressure and possibly add some r134, well the yellow hose has no adapter for the can. Now we are off to find the answer to my new problem. Shade tree mechanic-ing at its finest on this thread BTW. Now all I need to know is what the readings should be when running a static test with the car off and on. Time to start digging.

Chris

It's in your service manual.

What's that you say?

No service manual?

PS - The snow shovel couldn't keep up on the drive home yesterday.

 

[sirhc76]

Found the pressure info in the service manual. Current reading on my car prior to any freon 50PSI on the high side. I bought a tool and tightened the shrader valve on the low side, it was bubbling prior to that. I then added one can of R134 and cold air started blowing. Looks like at 90° air temp my high side should be 210-270PSI. Sadly the car over heated while I was in the process of doing this. This makes me wonder if my belt is slipping. I also noticed that my fan is shaking like its out of balance. Fun times ahead.

 

[dave6666]

Found the pressure info in the service manual. Current reading on my car prior to any freon 50PSI on the high side. I bought a tool and tightened the shrader valve on the low side, it was bubbling prior to that. I then added one can of R134 and cold air started blowing. Looks like at 90° air temp my high side should be 210-270PSI. Sadly the car over heated while I was in the process of doing this. This makes me wonder if my belt is slipping. I also noticed that my fan is shaking like its out of balance. Fun times ahead.

I might have mentioned yesterday - maybe not, I was running light on beer - that my '01 runs at least 10 degrees hotter with the AC on. More engine load, preheating the air to the radiator. Not so noticeable when on the freeway though. Just a tad off then. Makes me figure it's more the condenser pre-heating the air.

Anyway, be sure to bump up the rpm's to about 1500 when checking pressures.

 

[bluequadcab]

We add dye into all of the trucks in our fleet. Dye is ok for all appplications that I know of. The dye leaves a stain on whatever it hits or leaks out of. You then use a black light and yellow glasses to see the dye.

Check your low and high side valves as well. Most are a Schrader valve and over time they can loosen up a bit. It takes a special tool to turn them back in.

The other thing is that if you have leak, you may be getting air into the system and with most air comes moisture. Moisture will make any a/c system run poorly. The system should be completely evacuted and vacuumed down before charging.

Dave is right as well. Too much oil will cause the system to run very poorly or even destroy a compressor. Generally, we only add oil to the fleet vehicles if they have had a complete system failure. If you do add oil, I would recommend not adding much more than 2 oz. There should be a sticker on the car that says how much oil and refrigerant should be in the a/c system.

One more thing about charging with the cans... You can assume that there is 16 oz. of refrigerant in the cans but without an a/c machine or correct guages, you don't really know how much is currently in the system. It's generally best to take the vehicle to someone that has an a/c machine. Even if it needs work, you can have them **** everything out of the sytem, take the car home and do the work yourself. When you are done, take it back and have it vacuumed down and recharged.

I'm and HVAC tech, but the only Auto a/c I work on is my own. I have 3 different cans of R134A, and no there is no R136A, and they range from 12oz to 13oz and some have sealer. Although there technically is 16oz in a pound of refrigerant, you aren't getting the 16oz in a can. Also, you can't get all the refrigerant out of the can because the pressure would have to be 0 psi for that to happen, so I would estimate you're getting about 10 oz from a can. Now if you bought a 15 or 30lb cylinder, that's a different story. too expensive and too much for one user. The older die wasn't UV die and you could see the leak as long as it ran long enough in your system and you could see the part that was leaking. Manufacturers in HVAC didn't like it and voided the warranty because it coated everything in the system. The newer dyes are ok. I have had the porous hose issue in the past with a dodge but not the viper. I now use UV dye and you need a UV lite and special glasses to see it and it must be dark. Again, you have to be able to see the part thats leaking. The glasses not only protect your eyes from the harmful UV rays, they also block the blue light and make it easier to see the dye. I agree that adding to much oil the the system may shorten the compressor life and slug it.

 

[bvk]

yeah AC repairs are not to be undertaken lightly. Best bet it to at least get a shop to recover the refridgerant before you take anything apart at home, its illegal to vent R12 ot R134A.

I've just been through this on my other cars, here are some great videos on A/C workings, troubleshooting and basic repairs:

Car Air Conditioning Repair | ExpertVillage Videos
How To Videos - Auto Air Conditioning Retrofit & Recharging Instructions

and a good article on A/C basics:
How To: Auto Air Conditioning System Basics

 

[hou99gts]

Autozone has some kits on sale for us "Do it Yourself" folks, see link below:

http://www.autozone.com/images/in_our_stores/promotions/circular_pg4_0626_08.pdf