Hmmm....A/C Recharge - Am I on the Right Track?

[jgrakla]

Hi all,
So, I am trying to recharge the A/C on my Viper. I am not sure whether I am on the right tack and should keep going, or stop. I found the system was so low the compressor wouldn't come on. So I removed the pressure switch and jumpered it. The compressor came on. I put in about half a can of refrigerant and then reinstalled the pressure switch. Compressor came on by itself then. I kept filling down to about 5/6ths of a can. Got the indicated pressure on the low side in the correct range at 55 psi. But the suction line is not cold and the sight glass is not clear. The sight glass looks opaque, not clear. I can see fluid moving through at high velocity....it looks like a milky fluid moving through, not a clear liquid. The service manual says keep adding until the sight glass is clear, but I am not sure how "clear" it should be. I am questioning whether I should continue adding even though I am already at 55 psi. The air is blowing cooler than it was at the dash vent, but the temp there is measuring 70 degrees, not the 39-50 degrees the service manual says it should be.....so wondering if any of you who have done this before could guide me....do I keep going and add more refrigerant? Or do I stop and take it to a A/C service shop?

Thanks for any guidance!

Jason

 

[craig_g]

Do not put any more freon in it. You can over charge it and blow out seals/lines all kinda of stuff. Give me a min and I will see how freon it holds.

 

[craig_g]

Why year you got ?

 

[craig_g]

nevermind i looked it up in your other posts. 1994 right ? A/C Refrigerant Specifications Capacity 1.88 lb (US) if your overcharge it wont blow as cold either. what size cans were you adding ? .5 lbs ?

 

[MoparBoyy]

you should really vacuum the system to get any moisture out of it. a shop with a real a/c machine can recover, vacuum, and charge the system properly in an hour and for less than $200...

 

[jgrakla]

nevermind i looked it up in your other posts. 1994 right ? A/C Refrigerant Specifications Capacity 1.88 lb (US) if your overcharge it wont blow as cold either. what size cans were you adding ? .5 lbs ?

Yes, it's a 94. Have a 10 oz can.

 

[jgrakla]

Do you think it is moisture that is causing the sight glass to not go clear?

 

[craig_g]

drive to my shop in eastern iowa ! I charge $89.95 !! lol

 

[MoparBoyy]

drive to my shop in eastern iowa ! I charge $89.95 !! lol

ya i think we charge $149.99

 

[craig_g]

yea you have way too much in it. get it to a shop and have them **** it all out and recharge it.

 

[craig_g]

$149 at a dealership is actually a good price !!

 

[Bird325]

+1 ... unless you're in an emergency (taking the wife to dinner) type of situation, do it right and **** it out and then start from scratch. I added some freon year before last and had that same sight glass situation and a less than cool interior. Last summer, I borrowed a set of gauges and vaccum pump and did it right and the difference was amazing. Others on the sight have many times say 'take it to a shop' or do it yourself, but that ALWAYS involves checking for leaks, fixing them and then sucking a vaccum and letting it sit ... **** it out again and then add the freon. It's worth the extra effort/cost to do it right.

If you haven't already replaced the O-rings, do that while you're at it. There are a number of threads about it on the board and it is a quick repair that will make a big difference in how long your freon lasts. If you have a shop do the O-rings, don't let them charge your for more than 30 minutes of labor ... we did two cars in my driveway last summer and nobody took more than about 20 minutes with standard tools.

 

[jgrakla]

sounds like good advice....thought I would give it a try with the recharge cans......but guess I wil ltake it to a shop instead to get it properly evacuated and recharged.

 

[2BADD-4U]

It all depends if the system was bone dry of any charge when you started or not. If it was, you have a system full of air (non-condensibles) This will cause higher than normal pressures when running. Now if the car had a partial charge and you simply added freon...charge untill the site glass is clear...it should look like nothing is flowing thru the site glass when clear.

The best thing to do is to use a manifold gauge set, and a vacuum pump. Using both high and low side gauges tells the complete story.

Normal running pressures will vary ...low side when running will be approx. 25-40 psi...high side approx. 200-350 psi running...there is no set pressures as pressure and temperature are both linear thru out the system. Meaning they go hand in hand in the system...as the temp increases...so does the press...and vice versa..

When you saw your siteglass opaque, and flowing fast...you were ok to add more freon...you can charge untill the site glass goes clear...watch it next time you are recharging the system.

Yes ultimately the vacuum pump and gauges are best...but for the occasional recharge like I had on my 02 gts...the system needed about a can a year.

If you notice that the compressor short cycles on and off...the system is just a little low on charge, and add 134a untill glass is clear. There is a low pressure switch for safety to protect the compressor from running if all charge is lost. Now some cars have a high pressure switch which shuts off the compressor if the high side gets too great of pressure...say 450psi.

When charging .....rev the engine to about 1500-2000 rpms to simulate load conditions....to full siteglass.....air temps out the vents average 38-55 degrees according to load and outside air temps

Good Luck!

ah that will be $89.99 lololol

Dave

 

[jgrakla]

So I am already at 55 psi on the low side on a 90 degree day and site glass still not clear after adding only 1 can. But I have no idea what I started with. I think you are probably right about the non-compressables. Is there any way to purge the air from the system?

 

[MoparBoyy]

So I am already at 55 psi on the low side on a 90 degree day and site glass still not clear after adding only 1 can. But I have no idea what I started with. I think you are probably right about the non-compressables. Is there any way to purge the air from the system?

air? no. you have to get the whole system vacuumed down to remove everything.

 

[jdeft1]

May as well fix the leak too.......

 

[AZTVR]

Just an FYI. You can "rent" a vacuum pump and set of AC gauges at Autozone. (At least around here.) Actually, you buy them and then get a refund when you return them. You do need to have a good idea about what you are doing, though.

 

[2BADD-4U]

jgrakla..... Yes, there is a simple way to purge the air from a system.....not 100% but it does help .........IF your system is completely empty, you can do a quick PURGE to your ac system. We have done this with good results many times on ac systems much larger than a car's system. With great results. The idea is to install a charging hose conn. preferably with manifold gauges and a can of freon....to a port on the system lines ....to either add LIQUID OR VAPOR refrigerant in one acess port and have another hose (for bleeder) or depress the schraeder valve core depresser pin "in" on another downstream line connector fitting to be used as a BLEED port (for the air) This does work in a pinch with great results

You should have 3 access ports on the ac system...high side, low side, and liquid line....place the freon purge line to bleed the longest run of the system...the condensor is the largest coil in the system so try to purge the high side to the low side for best results.

What you are doing is forcing freon, either in liquid or vapor...preferrably liquid as a means to travel thru-out the ac system...pushing most all air out ahead of it untill there is only freon liq. or vapor...Remember there is NOT a whole lot of air in a system even when empty...the lines are small, and the complete charge is usually 1 1/2 # of r134a

What I want you to do at this point is to install your gauge on the low suction side (charging side)...with the car OFF...the pressure should be near 100-150 psi holding steady. Now watch the gauge when you start the car and then start the ac system...the pressure should start to lower....from 100# to say 55# or lower. now have someone else hold the revs at 2000rpms, or you can do it at the twin throttle bodys...and watch the pressure...it should even go lower if the compressor has good compression and good valves...if the site glass is flowing bubbles or is whitish,,,opaque...simply add more charge until it is clear...

Feel free to email or pm [email protected] If you need my cell..I will provide it for you..

I have been doing HVAC for a little over 35 years...cars, residential, commercial, industrial chillers etc....

UNIVERSAL CERTIFICATION


Dave
God Bless!


2002 FE GTS #338
Kawasaki Ninja

So I am already at 55 psi on the low side on a 90 degree day and site glass still not clear after adding only 1 can. But I have no idea what I started with. I think you are probably right about the non-compressables. Is there any way to purge the air from the system?

 

[eucharistos]

jgrakla..... Yes, there is a simple way to purge the air from a system.....not 100% but it does help .........

thanks for the info fellow follower

 

[2BADD-4U]

Glad to help out guy's! This is usually what most do it your selfer's are looking for!

Blessings!
Dave

 

[jgrakla]

Ouch. So I took the car up to the dealer today. No simple evacuate and recharge. The estimate is $1800.00 to fix the A/C. The biggest problem was a leak at the Condensor around lower fin area. Apparently fluid is leaking and caking in the fins. That is an $1100.00 part with labor. Guess I will just do without A/C. Although now that they have the system completely empty I am wondering if it would be worth charging up again myself now that I know the starting place is zero. The recharge kits have some sort if stop leak additive but I don't know if that would stop what appears to be a major leak at the Condensor.

 

[MoparBoyy]

Ouch. So I took the car up to the dealer today. No simple evacuate and recharge. The estimate is $1800.00 to fix the A/C. The biggest problem was a leak at the Condensor around lower fin area. Apparently fluid is leaking and caking in the fins. That is an $1100.00 part with labor. Guess I will just do without A/C. Although now that they have the system completely empty I am wondering if it would be worth charging up again myself now that I know the starting place is zero. The recharge kits have some sort if stop leak additive but I don't know if that would stop what appears to be a major leak at the Condensor.

DO NOT, use stop leak in a/c systems.

 

[eucharistos]

DO NOT, use stop leak in a/c systems.

mb, i know you are a tech (so props to your post), but i had good, really good results with an ac leak seal product (not the cheap old stuff at wally world), they are not all the same and some are "hi tech" and in some situations worth a try

op. ymmv

 

[MoparBoyy]

mb, i know you are a tech (so props to your post), but i had good, really good results with an ac leak seal product (not the cheap old stuff at wally world), they are not all the same and some are "hi tech" and in some situations worth a try

op. ymmv

how do you know??!! you stalking me?!? LOL

sure it may work, so does putting stop leak into the radiator to fix that leaking head gasket. its a Viper, why not fix it the right way? Once in introduce stop leak into the system, the whole system has to be replaced to repair it properly. You can never get any professional a/c work done on your car. you get stop leak into a shops a/c machine, they gonna charge you the $4k for a new machine, cause it instantly ruins it.

if anything, I would say yank the condenser out, take it to a shop that can repair it.... i'm sure way cheaper than $1100 and more than filling your system with slime.

 

[darkostoj]

best way is to evacuate and then charge by weight

for $150 you can get your own manifold gauges and vacuum pump and do it yourself, then have the tools for later on