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1996 deville ac service


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My 1996 deville is about to get its first ac service ever.  The last 3 years or so, the system required 1 can of 134a to get running again.  I have the tools to vacuum out the system to 0, and all the gauges to perform a refill to specs.  Do any of the ac experts on here have any advice or anything else I should do?  I take a while to do things, but I like to have lots of time to plan and order any additional parts, etc.  btw, what are the specs?  How many small cans do I need? Any oil?  Should I put dye in just in case I developed a leak? Replace any known parts that break after 20 years of use? (Sensors and not compressors). THANKS?

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The spec. is 2.0 lbs of R-134a (32 ozs.)  It will take close to three 12 oz. cans.  You'll loose 1/2 oz to 1 oz. by the time you change the cans and burp the air from the lines so three cans will be just about right. 

R134a is R134a - buy whatever is cheapest.  It might be a good idea to install some dye in the system in case there is a future leak.  One 12 oz can or R134a with UV dye should be good.

I am surprised the compressor case seals haven't started to leak.  That seems to be the most common issue with that model compressor.

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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speaking from experience.

Always vacuum down to 20HG for at least 1 hour to boil off any moisture and contaminants.

0 is not nearly good enough. It has to be negative pressure to properly charge.

unplug the pressure switches and look for seepage in the plug, and around the base.

(one is by the firewall in the high side line, other is by the compressor near the radiator)

If the dryer is original replace it. 

Inspect the compressor, If it is oily, the clutch is noisy, or very rusted, replace it.

Replace the orifice tube. The system will thank you. It is located in the expansion tube to the dryer.

DO NOT. I repeat do not use stop leak of any kind. It is harmful to the system and to the recovery equipment. (both of which are not cheap)

Both of my Caddys have been well serviced and although they are 20 years  old they blow ice cold.

As spring approaches I will be right back into the swing of AC services. I work on them pretty well daily in the spring and summer.

If you do not have a vacuum pump and a oil injector I would recommend just putting everything together and take it in to have the system vacuumed, oil added, and charged. (best results) 

These tips are the best I can give.

GM FAN FOREVER

Nice, clean, luxury= fine automobile

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No need to replace the accumulator as part of a routing evacuate and recharge.  The deep vacuum will pull any moisture out of the system.  A GM factory air conditioning engineer told me that many tears ago.  Compressor vendors will often state that the accumulator needs to be replaced in order to honor the warranty but unless the accumulator is puking desiccant into the system, which is almost unheard of, replacement is unnecessary.

If the orifice tube is replaced, be sure to note the direction that it is installed - installing it backward will destroy the low pressure temperature sensor.

So many compressors are replaced due to the case halves leaking when they can be resealed for the cost of a $25.00 seal kit, a $30.00 shaft seal and a little labor.

 

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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I replace the dryer usually due to contaminants. I have cut open some and have found mixed results. 

GM FAN FOREVER

Nice, clean, luxury= fine automobile

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  • 3 months later...

Back in April, I used my vaccum pump and gauges to pull -30 on the system.  I let it sit overnight, and no leaks.  I then added dye to the system, and as KHE mentioned added 2lbs of 134a.  I also used my thermometer probe to monitor the temperature from the vents.  So far, the system is working great, and On a hot day, I see temps blowing out of the vents at 36 degrees.  I have not connected the gauges up to check the levels of refrigerant, or checked for leaks with my uv flashlight, as I didn't realize how hidden up in the engine the ac compressor was!

vaccuum pump and gauges from eBay $79 with free shipping

digital ac vent thermometer from eBay $2.00

uv flashlight from eBay $3.00

the dye I got from advanced auto, and it was the can with the ac charge adapter $9.00

the 3 cans of refrigerant cost me ~$18.00

hopefully this charge lasts me 20 years, but with a 20 year old system that was never serviced, I am doubtful.  But at least I have the tools to keep it in service.

 

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That is great winterset, I need to get up to speed with AC charging.  Kevin was very helpful to me when I rebuilt the AC on my 96.

That is very cold air at 36 degrees you are getting I am surprised

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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51 minutes ago, BodybyFisher said:

That is great winterset, I need to get up to speed with AC charging.  Kevin was very helpful to me when I rebuilt the AC on my 96.

That is very cold air at 36 degrees you are getting I am surprised

The 36 degrees is for a short bit on a really hot sunny day with the fan speed on low.  Most of the time it is about 42 degrees with the fan on low. With the fan speed on auto, the temp is in the mid lower 40's. I understand that sun sensor on the dash controls how cold to set the air.  But it's good to know that it can get that cold if it gets hot outside.  I recall hearing that charging up an AC is an art.  The investment in this set of low end but good quality tools was well worth the money.

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:hatsoff:

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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