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Re Man Denso Compressor for 968

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Old 12-26-2017, 06:29 PM
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jsheiry
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Default Re Man Denso Compressor for 968

Pulled my wifes car in the garage to tighten the belt (they were new, and logically stretched a little...) Got to looking at things and when I put my hand on the A/c compressor the whole thing would move slightly. Thats not good I thought and after careful inspection I found the M8 bolt on the backside gone...and the M10 bolt on the front side broken off! Hmmm no wonder the belt screeching a little I thought. Had to pull much off the front of the car to try to drill the remainder of the broken M10 and use easy out to remove. (side note... I have never had an easy out work when really really needed) drilled hole and promptly snapped the easy out. F..... NICE Now there is NO real way to get this off the bracket, cuz your not drilling the remainder of the easy out with such little space and a wimpy angle drill, you just cant get enough pressure. I had to sawzaw the ear of the aluminum bracket to remove the compressor. (words are not enough to express nearly 8 hours on what started as tightening the belt job)

OK I say, car has 150K on the clok and probably could use a fresh compressor. (the kind of logic that sets in after 8 hours of trying to remove the old one)

I order the following Denso Compressor (Denso Reman) 471-0128 Go ahead and look it up anywhere on the web and its the one sold for this car. 1995 968

It arrives and Im happy to just be putting things back together at this point, damn the money lets just get this thing outa my garage! BUT wait I notice a sticker on the back that has the correct part number and then one that says R-12? How can that be I say cuz '93-'95 968's are all R134. The '92's are R12 like the 944's but there is a seperate part number for those.

I look up on Denso's site and sure enough http://densoautoparts.com/find-my-part#searchResults and the part shows up properly but when you look at the details it says R-12 refrigerant.

Now look up the '92 968 and see what you get 471-0127. Look at its details and you see R-134 Interesting and probably well documented here on RL but never thought I would have to correct the OEM manufacturers product info to get the correct compressor.

Now going to purchase a 471-0127 so that I receive one with the correct oil in it, otherwise the same damn thing. I suppose I could just drain the oil, refill with proper R134 pag oil rotate around a few times, drain, repeat and then fill and be happy that the correct stuff is in there BUT you should not have to go to so much trouble....on a recent purchase!

Anybody seen this or care to show me the link where this is well documented?
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Old 12-27-2017, 01:48 AM
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Like getting kicked in the shorts! The easy out thing is so true. I have three different sets of four (each with the same size broken) ...I actually get excited when I can use a size that is not broken so I don't have to buy a new set.

I asked my brother in-law who teaches retrofitting A/C systems (and AST certification) at a local college. He said that cars after 1996 were required to have R-134a. He also said that retrofitting is NOT required in cars in many areas of the US but is a practice which includes changing the filter/dryer or accumulator as well as seals and hoses that were compatible with R-134a. This info and time frame seems to fit the info shown in this link: https://en.wikipedia.org/wiki/Dichlorodifluoromethane

I am not sure exactly when Porsche stopped using R-12, however, auto manufacturers were given the recommendation to begin the changeover to R-134a in 1992 and complete the changeover by 1994 but was not officially banned (for new cars) until 1996.

I'm sure you know this but PET shows two different compressor part numbers for the 968, one for '92 (same as the '86 and later 944) and one for '93 on....just a theory...the earlier version compressor was in fact more compatible internally with R-134a than the later version and do not fail as often as the newer version...or the parts necessary for conversion of the later version are not easily found.

Check out this link also: http://www.refrigeration-engineer.co...hp/t-1047.html
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Old 12-27-2017, 08:53 AM
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Originally Posted by spark1 View Post
I am not sure exactly when Porsche stopped using R-12, however, auto manufacturers were given the recommendation to begin the changeover to R-134a in 1992 and complete the changeover by 1994 but was not officially banned (for new cars) until 1996.

I'm sure you know this but PET shows two different compressor part numbers for the 968, one for '92 (same as the '86 and later 944) and one for '93 on....just a theory...the earlier version compressor was in fact more compatible internally with R-134a than the later version and do not fail as often as the newer version...or the parts necessary for conversion of the later version are not easily found.
Yes Im fairly sure of the '92 968's being R12 with all the rest '93 - '95 being R134. With perhaps Porsche re-vinning any '92s as '93s as a completely unique and different thing.

The issue is that when you put in any reputable parts search for a rebuilt Denso compressor on '93-'95 you get a part number that is 471-0128 and when you receive that part it contains the oil for R-12 installations AND when you look up the older cars like a '92 it gives you a rebuilt Denso compressor with a part number of 471-0127 and that has oil in it for R-134a systems. Then if you look up directly on Denso's site it confirms the refrigerant types for each of these incorrectly. I think there system has these incorrectly and therefore every single one sold under all these search engines have incompatible oil in them for the wrong year/application. The best I can tell is that the compressors are identical mechanically but have improper oil for the application. That was my thought in this thread that if you buy a rebuilt Denso using any of the common search engines including their own you get a compressor with incompatible oil in it for your application.

I noticed the 2 stickers on my Denso factory rebuilt unit: one said 471-0128 and the other said Denso and very small print said R-12 and had the Denso oil number that was associated with R-12 systems. I thought that perhaps someone mis-labled the one I received but the more I looked into it they have these part numbers incorrectly associated with the cars they are actually rebuilt for....It also says the same on their website when you look at the information tab. Then put in an older car and have the 471-0127 compressor come up, push the information tab and it says R-134 refrigerant.

I just re-ordered a compressor for a 92 because its a 471-0127 part number and according to Denso site has R134 refrigerant and the proper associated oil. I expect that when it arrives that it will have two stickers as well...one that says 471-0127 and one that says in small print R-134a and the Denso oil number associated with R-134a systems.

Anyone who buys these under the Denso rebuilt banner/search engines on the web probably has incorrect oil in the compressor they receive even though they are perfect bolt up mechanically same compressors. 1000% sure there have been many incorrectly installed based upon their incorrect associations/part numbers.
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Old 12-27-2017, 10:12 AM
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Paul Waterloo
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I also had the ear break off of my 968 compressor (and sadly, the same thing happened to my 951 last summer, but it's the back ear vs. the front ear).

I replace the 968 compressor with the 471-0127, don't know if I was lucky or good, can't remember back that far. But I did do a pretty detailed write up:

https://rennlist.com/forums/968-foru...placement.html

Best of luck!
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Old 12-27-2017, 11:37 AM
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Standard procedure when installing a "new" or "rebuilt" compressor is to dump out any oil in it, properly dispose of it, install new oil.
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Old 12-28-2017, 02:09 PM
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This ear breaking stuff is generally due to people hamfisting the belt adjuster strut without first loosening the pivots and the end bolts on the strut (turnbuckle, adjuster) that allows adjustment of the belt. The strut can easily break itself or the accessory ears or the engine mounting points. This can cause the thing to come loose on the highway and drop parts, toss the belt, etc. It's a mess.

If this turnbuckle is stuck take it straight off and sort it out on the bench, used units are cheap also so replace it if it's not in good shape.

My procedure:
1 - break loose the strut locking bolts (one is reverse thread) but *do not turn it for adjustment yet*
2 - loosen the turnbuckle end bolts
3 - loosen the pivot bolt (AC or PS depending on what you are adjusting)
4 - adjust, but be careful. The strut is strong enough to lift the car and can easily break stuff with little hand pressure on your wrench.
Reverse procedure to tighten back up.
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Old 12-28-2017, 03:32 PM
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Originally Posted by Jfrahm View Post
This ear breaking stuff is generally due to people hamfisting the belt adjuster strut without first loosening the pivots and the end bolts on the strut (turnbuckle, adjuster) that allows adjustment of the belt. The strut can easily break itself or the accessory ears or the engine mounting points. This can cause the thing to come loose on the highway and drop parts, toss the belt, etc. It's a mess.

If this turnbuckle is stuck take it straight off and sort it out on the bench, used units are cheap also so replace it if it's not in good shape.

My procedure:
1 - break loose the strut locking bolts (one is reverse thread) but *do not turn it for adjustment yet*
2 - loosen the turnbuckle end bolts
3 - loosen the pivot bolt (AC or PS depending on what you are adjusting)
4 - adjust, but be careful. The strut is strong enough to lift the car and can easily break stuff with little hand pressure on your wrench.
Reverse procedure to tighten back up.
Joel,
Agree with procedure above. Mine did not break the tab off the compressor, this appears to have been lost in other peoples descriptions of similar stories. The front M10 bolt broke off and could not be removed from compressor (at least by me and huge effort, crying, cussing, begging, drilling, easy outing, NO JOY) and the rear M8 bolt was just mysteriously gone, and as nutty as it sounds the compressor could not be removed from bracket without getting this broken bolt out so after much effort had to just cut the ear/tab off the compressor mounting bracket that bolts to the block just to get it out of there. Now I did this because I had another one of those brackets sitting across the garage and thought that once the compressor was out and in a better spot that I still stood a chance of getting the broken bolt out of it. This also did not work out so in the end I should have just cut the ear off the compressor that had the broken bolt rather than cutting the bracket (but something had to give and I was hopeful of still getting bolt out without having to evacuate the AC system etc...etc..) Now that Im ending up with a near new compressor and will have to evacuate and charge hindsight is 20/20 on the cutting of the compressor to block bracket.

I ultimately marked my two adjusters with a red sharpie L on the side that is left handed as I always seem to forget which end it is and spend some time grunting to figure out.
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