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84 a/c compressor noise



My compressor is starting to make a knocking noise. Still pumping cold air, but doesn't sound good. Also I noticed some red colored oil around it.

Is my compressor shot!? I seen Ecklers has a 134 kit for $400.00 that includes a new compressor. Any comments on that?
Jun 20, 2002
Tallahassee, FL
none right now :(
I have heard many horror stories about upgrading to 134a, I understand the particles are smaller, and they tend to leak easily.


Does it appear that the oil is coming from the front shaft seal?

I have had compressors run noisy for 50,000 miles with no ill effect. On the other hand, if a compressor fails internally, it spreads bits and pieces throughout the system requiring THOROUGH flushing, followed by flushing, then you flush, then follow up with a flush, then finish it off by thoroughly flushing. One little piece of old compressor can destroy the new one.

For this reason, replacing an EXTREMELY noisy compressor might not be a bad idea.

Now for the 134 conversion issue; R12 now goes for about $29 per can, and due to the fact that cars requiring it are rapidly coming to the end of their lives, the demand for R12 is decreasing which should show an R12 price decrease in the coming years. At this price R12 is the least expensive major component in your a/c system. When you change to 134, you lose about 20% of the cooling capacity. If you live in Canada, this is probably not that big of a deal. If you live in Houston and drive alot stoplight to stoplight, then it certainly is a big deal.

To do a proper 134 conversion, you need to flush the mineral oil out of the system by breaking all connections and thoroughly flush with a proper solvent to remove the oil. This is not a flush over and over operation like is required during compressor failure, but it is still a bit of a project.

After the flush, you need to reassemble with 134 compatible o-rings and a special lubricant called Nylog. Then replace the filter drier and put the correct amount of ester oil in the system. Follow that with thorough evacuation and charging.

If you were to stay with R12 and change your compressor, you could simply replace the filter drier, the compressor, add a few ounces of mineral oil, evacuate and recharge. It sounds as if you currently have a charge of R12, so you can have that recovered and basically sell it to the a/c shop that recovers it.

One more thing, be extremely careful about purchasing a rebuilt R12 compressor, most of the rebuilts are junk. I would only purchase a rebuilt from www.ackits.com. The only source I know of that may have a quality rebuilt, otherwise purchase a new one and be happy. Remember a failed compressor requires; flush, flush, flush, flush,......... You don't want to do this after saving $100 on a compressor.

Summation. I changed over my '88 very successfully, but it was a lot of work and IT has a Nippondenso, not an R4. This system lends itself well to conversion. I think they were already planning on it at that time. Your system with the R4 compressor would be much better served with a new compressor if you want to be careful, and staying with R12. I know, I don't like paying $29 per can either, but I believe it will be your best bet. Just make darn sure you're not putting it into a leaking system. If you have a leak, you need to fix it regardless of refrigerant used, so it should not be a factor in your refrigerant decision.

Good luck,


The red dye you are seeing is a leak detector someone has put into your system. It would appear that the seal in the front of your compressor is leaking. It is possible to replace the seal...as well as the bearing that is probably making the noise.
Last time I checked can's of R-12 are going for 100.00 a pound. And you need to be EPA certified to buy them as well as work on ANY Motor Vehicle Air Conditioning (MVAC) system per the federal government part 609 of the clean air act. I am certified and have been doing this for a number of years. Some of the things left out of the above reply include replacing the orfice tube which easily gets clogged and causes system wide degradation. As far as replacing the freon...you can stay with R-12 or try Enviro-safe which is a drop in replacement and sells for 6.95 a can and works just as well if not better then R-12. If you wish to be certified it is really easy...go to www.qwik.com and for 20.00 you can download the manual and take a 20 question open book test and receive your temp card then and there. Then you are legal to work on your own system. Don't get caught without a card ....the fine is upwards of 25,000.00...


Yes, I forgot about the orifice tube. I'm usually working on systems with an expansion valve instead of the orifice tube.

R12 is no longer 100.00 per can, in fact I never personally saw it that high. It can be had at my local NAPA store for $29.00 per can, with 609 certification of course. If you want to mess with it, you can buy it on ebay even cheaper, with a 609 certificate of course.

You can get your 609 for $15.00 and an hour or two of open book test at: www.imaca.org.

There are many "drop in" replacements such as enviro safe on the market. They all fall into one of two categories: blends or flammables.

BLENDS - The problem with blends is that if there is a leak, the components of the blend leak at different rates. This means that after repairing the leak you must recharge starting over again from scratch. The use of blends also ultimately leads, in many cases, to contamination of our R12 supply when recovering the refrigerant.

FLAMMABLES - These are widely used, but are ILLEGAL. I have read much debate about whether or not this poses a real risk. There are all sorts of stories that justify their safety. Regardless of whether they are dangerous or not, the fact remains they are illegal.

Good luck,

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