PontiacBonnevilleClub.com

For the longest time, my Bonneville had no A/C. All the refrigerant had leaked out years ago, so when I pushed the A/C button, all I got was a blast of warm air. After taking a road trip to Maryland in a 98 degree heat wave, I was fed up with having no A/C. Taking my car to a professional was not an option since I didn't have the $800 to have them fix it for me, so I overhauled the A/C system myself. I replaced all the O-Rings, the accumulator, the orifice tube, the compressor, and the condenser. Total cost was around $350.

Note: If you're not comfortable with working around A/C systems, take it to a professional to get it done. Only service your own A/C system if you know what you're doing, or if you're crazy enough to take on the task. You are dealing with refrigerant under high pressure, and if you don't know what you're doing you can injure yourself. If you do a R152a conversion, make it clear that there's R152a in the system.

Getting the tools
In order to do any A/C service on your own, you will need to get the proper tools.
If you have one of these, find your nearest trash can and throw it away. These cheap gauges are as accurate as your daily horoscope, and they only "show" low side pressures.

Then, run to your local auto parts store and pick up one of these. I picked mine up for $50 at the local Harbor Freight.

Manifold Gauges are absolutely critical to any A/C service job. In order to diagnose your A/C system properly, you will need to know the pressures on both the high and low sides.

You will need a vacuum pump. They cost around $150 at Harbor Freight, but you can rent one from an auto parts store.

You will need a side-tap. I had trouble locating one at the local auto parts stores, so I ordered one online.

Charging the system
After overhauling the A/C system, I vacuumed it down and let it sit overnight. The next day, I charged it up with R152a, making sure to purge the hose first. H-Body cars require 2 pounds of R134a, which converts to 1.28 pounds of R152a.

You may be wondering why I didn't go with R134a, and here's why.
- R152a(otherwise known as computer duster) has a better cooling capacity than R134a.
- R152a has a way lower environmental impact than R134a.
- A 3 pack of computer duster costs less than 1 can of R134a.
- It takes less R152a to charge the system.

Now, the A/C in the Bonneville works better than ever, and I saved a lot of money.

What route did you take for oil?

I've found that just because a system holds vacuum doesn't mean it's sealed properly, but being that you replaced all the seals and the compressor you probably already replaced what was leaking. If you have a local NAPA hub they always have the can side tap in stock.

RJolly87 wrote:What route did you take for oil?

I used PAG 150 oil.

Wow, I never heard about using R152a/computer dusting propellant. I can buy R134a from $6-7 what are the benefits beside a small difference in price? Considering the parts cost hundreds of dollars the slight savings would be offset by voiding the compressor warranty due to improper refrigerant.

It's cheap, it cools better @ lower head pressures (so less stress on the A/C compressor), and it's environmentally friendly. Not sure that which refrigerant you use is going to void the warranty, maybe if you used the wrong oil but not refrigerant.

I have also heard that R12 systems like it better than the R-134a conversions as well. It would be at the top of my list if I had to do one of them.

Sounds like a lot of hard work. I've done the replacement more than just a couple of times, but that was back when dirt was new. Hope you were able to do a good back-flush job. Amazing how much trash builds up in those old systems. - BC

EDIT: I went to www.wikipedia.org to find information on R152-a. Wikipedia sez R152-a has been approved as a replacement refrigerant for R134-a. - BC

Is the cooling Temps a big enough difference to constitute a change from 134? A/c in my olds is cold but could definitely be a lot colder versus my other vehicles. I might be not so mad about the under powered blower motor if the air itself was colder. It's great at speed and even at idle but is a great bit warmer at idle. Information is appreciated thanks!

I wouldn't convert your system if you still have 134a in your system. If it ain't broke, don't fix it.

here is a write up on this subject http://www.s10forum.com/forum/f135/how- ... on-493953/ I found this very interesting

As far as cooling temps go, my A/C gets colder than my dad's Impala, which is a 134a system. Funny thing is, dad thought I was nuts trying to get the A/C working again.