AC Compressor purchase 85 300TDT??? - PeachParts Mercedes-Benz Forum

shear2001 · #1 04-16-2004, 09:15 PM

Has anyone had any luck with autozone or Advance auto parts rebuilt AC compressors? I'm ready for a new one but are not sure which way to go. I don't want to spend much which limits me to a rebuild, however I don't want to be replacing it in 8 months. My system is already converted to the new type of coolant. Any suggestions appreciated. I already purchased a new dryer .

kerry · #2 04-16-2004, 09:24 PM

I looked at a 84 300td which had been maintained by Stu Ritter's shop for years. Lot of records. I assume they used good parts. Despite that, the compressor had been changed about 5 times. Each lasted about a year. Good luck.

shear2001 · #3 04-16-2004, 10:04 PM

This will be my third. Others where from junkyards. Maybe I'll have better luck. Who knows..

samiam4 · #4 04-16-2004, 10:49 PM

You can get a rebuilt from Pep Boys for $69 ? or $79.

Really, I've always had good luck with new R-4 compressors. I've purchased them from Autozone. My recently departed W123.912 had 140,000 miles on the compressor and still seemed OK. I think 125-200 would be normal. I've done 4 cars in recent memory.

Are you cleaning all the metal and old oil from the system by a strong flushing chemical??? Replace all the o-rings, dryer, expansion valve and any hoses that are suspect. It ussually runs me $350-500 in parts. I think most shops do the standard flush chemicals, but may not be diligent enough. A second way would be to add a filter into the suction line.

Unless you've got access to R-12 freon recycling& recovery equipment(or you're selling the car), I think it's false economy to put a rebuilt compressor on a W123. I haven't priced them this year, but for the last 3 years I've paid $199~!

Kerry- 1 year is crappy for any proper A/C compressor unless he's driving 150,000 miles a year!!

Michael

Eric Eliel · #5 04-16-2004, 10:56 PM

R4 compressors are not good candidates for rebuilds. The rebuilds are no longer reliable probably because a new one is not that much more. Therefore no one is spending any research $ on getting a better rebuild. Plus the distribution chain adds additional $ to the rebuild.

Wholesale price of R4 compressor is about $225 as I recall from a thread posted here about 2 weeks ago.

A new Nippon Denso is like $450, and there are decent rebuilds out there at about half that amount.

Are you seizing compressors or is the shaft seal leaking on all these rebuilds?

samiam4 · #6 04-16-2004, 11:18 PM

If you look tonight on-line....

Those new Nippon prices are obsolete- They are much more expensive now.

Michael

shear2001 · #7 04-17-2004, 05:42 AM

I do have a hose that's in need of replacing. I've never replaced any o rings or expansion valve though. Where are the o rings located? Thanks. PS. What flushing chemical are you reffering to? Thanks.. Brian

samiam4 · #8 04-18-2004, 09:29 PM

When I do a compressor- there is the expansion valve and dryer- those o-rings plus I replace the schrader valves since they are cheap and one of the most common leak points.

Flushing- I ussually do one part of the system at a time, so basically take things apart at the joints. Then I use Naptha or Acetone (1-2 quarts) and blow a plug of the liquid through the system. These both are nice and will leave a slight oil residue which will prevent corrosion.

Do it again and again with the flushing until it comes out clean. I use a jar/or can to ketch the residue with rags stuffed in it. 1-2oz plug with compressed air behind it.

Put fresh oil in each component or close to them, per the factory guide.
If I had a problem child with several compressor replacements- I'd be thinking "black death" and check. When I did mine, I found a large piece of aluminum upstream. It was quite amazing.

Michael

shear2001 · #9 04-18-2004, 11:42 PM

Thanks, you mention schrader valves , exactly where are they located?

#10 04-19-2004, 08:31 AM

First off I agree with Eric, R4's are terrible candidates for rebuild, especially by small rebuilders.

Secondly, when you lose one of these compressors if you don't THOROUGHLY and REPEATEDLY flush the ENTIRE system, and/or add a suction side filter, you are virtually guaranteed to lose your new compressor due to its ingestion of debris.

Good luck,

shear2001 · #11 04-19-2004, 10:58 AM

Where exactly should I install a suction side filter? Thanks. PS IS it like a normal clear fuel filter??

#12 04-19-2004, 11:32 AM

You will need to consult your local automotive a/c supply store. There are several things available. I would prefer an inline filter that gets put into the suction line just before it enters the compressor.

No it's not a fuel filter. A fuel filter deals with less than 50PSI. This filter deals with several hundred PSI.

Good luck,

Eric Eliel · #13 04-19-2004, 12:43 PM

Shear2001,

With all due respect, from the questions you are asking, you need to read all the threads on this subject that are available. It sounds as though you may not have done any A/C work in the past. (I'm trying to say this most graciously).

Even if you use a new R4, there is lots of additional information that if not followed will result in a bad installation. Then you will start a thread saying you didn't think a new R4 was worth the money because the system failed again. We ARE trying to save you some effort and hassle and money.

The basic questions are: Why did you go through 3 compressors? Leak at the front seal, a seized compressor, a pressure switch that isn't triggering the system off, leaking hoses, leaking o-rings, leaking everything else? Contaminated system......the list goes on. How do you know there are no leaks in the system? How did you determine the condition of the system?

All of this information can be found here at the site using the search engine. You can also read the posts at www.aircondition.com for more information.

I think you need to determine first why you went through 3 compressors before you start asking about o-rings.

(I hope my writing style was not too harsh, that wasn't my intent)

shear2001 · #14 04-19-2004, 01:10 PM

Thanks for the input, I'll give it a try, however, there is no such thing as local automotive a/c supply store in upstate NY. Thanks again..

Eric Eliel · #15 04-19-2004, 01:58 PM

First you have to test for leaks. With the information you presented you probably ought to find a good local A/C shop that can sniff any leaks for you. Do not throw any more money at the a/c system until you find the leaks AND detemine why the system went through 3 compressors. It takes a special tool to do this. The sniffer looks for hydrocarbons and sounds like a geiger counter. Find all the leaks first, repair the leaks with new parts, new o-rings on the hoses etc. Read about the flush agents.

Once you determine the condition of the system, lets talk about compressors.