Air conditionin function overview and retrofit/repair thread

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jacko
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Post by jacko »

Which Sanden compressor?
Jack
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dwcains
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Post by dwcains »

Dean
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sansouci
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Post by sansouci »

These are double pulley units. Do you have a double pulley setup? I don't on my 84 633.
--Ken
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jacko
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Post by jacko »

....and I'm wondering if the compressor cares if it's a dual evaporator system?
Jack
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Post by dwcains »

sansouci wrote:These are double pulley units. Do you have a double pulley setup? I don't on my 84 633.
--Ken
Just don't buy the serpentine pulley type and you're fine. You still only use one belt on the compressor.
Dean
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dwcains
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Post by dwcains »

jacko wrote:....and I'm wondering if the compressor cares if it's a dual evaporator system?
I've seen it mentioned in other threads and never heard of any issues, but I've never had my hands on a later car with the double evaporators.
Dean
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'87 Spider Veloce
'92 Spider Veloce
'08 350Z

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jacko
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Post by jacko »

I'll try to see if the Sangen tech support guys have any idea. Still a little bit wary of the $110 online fan and shroud. Can't find a good used one yet either. Maybe I can find somebody like FCP selling them with a better warranty.
Jack
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BlackBetty
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Post by BlackBetty »

jacko wrote:I'll try to see if the Sangen tech support guys have any idea. Still a little bit wary of the $110 online fan and shroud. Can't find a good used one yet either. Maybe I can find somebody like FCP selling them with a better warranty.
Let us know what you end up doing, I am in the same boat, getting ready to redo it all...
Pete
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Post by jacko »

Dean, will you give me the hole spacing and size from the brackets. I want to see if they will fit whatever Sangen's replacement for their 7 series compressor is. I emailed them already.

Jack
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Post by dwcains »

The mounting holes on the Sanden/Seltec compressors are spaced at 104mm on-center, but the bracket holes are spaced at 4 1/8". Not an exact match, but there is enough free-play in the holes (slightly oversized) so everything mates up fine.

I don't know that Sanden will be able to assist you, because if they do have a direct bolt-on compressor for a BMW, it won't be the same dimensions, and it also surely won't be affordable. That's the whole point of these custom brackets - so we can use the cheap, generic compressors.
Dean
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Da_Hose
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Post by Da_Hose »

A Nippondenso 6p (6 piston) is a common upgrade for large vans and full size luxury cars.

The Sanden 508 is a 7 piston pump. I don't see it having a problem with supplying a dual setup.

Jose
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dwcains
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Post by dwcains »

Probably more than you'll ever want to know about Sanden compressors:

http://www.sanden.com/objects/Sanden%20 ... Manual.pdf
Dean
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slofut
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Post by slofut »

As I remember from way back, there were three different displacement Sandens that worked on the e24. The larger one is what I used as recommended by Steve Haygood.
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jacko
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Post by jacko »

No, they don't show any direct bolt on. I'm just not sure if all of theirs use the same bolt pattern.
Jack
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Post by jacko »

E39 condenser fan assy's are $120 new on Rockauto in the US. Aftermarket. Lifetime warranty.
64548380780
Jack
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Da_Hose
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Post by Da_Hose »

Looking at the chart, the 508 is actually a 5 piston pump.

I would go for the big boy with a rear AC setup running R-134. That means an SD7H13/15.

Jose
1987 M6 - My dream car
jacko
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Post by jacko »

Jose, in theory at least....shouldn't the 7 piston one run smoother than the 5?
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Post by dwcains »

jacko wrote:E39 condenser fan assy's are $120 new on Rockauto in the US. Aftermarket. Lifetime warranty.
64548380780
I remember reading a thread on myE28 where a guy used a modern OEM condensor, and it may have been an E39, or maybe E34. That's all I recall, though, and don't know the details about the fan, hoses, etc. There's a good amount of working room behind the E24 grille, so there are probably several easy options.
Dean
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'87 Spider Veloce
'92 Spider Veloce
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dwcains
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Post by dwcains »

Da_Hose wrote:Looking at the chart, the 508 is actually a 5 piston pump.

I would go for the big boy with a rear AC setup running R-134. That means an SD7H13/15.

Jose
Why not just run R12? It's gotten cheap again, as demand must be down, and its easy to buy on eBay or craigslist. I've got 16 of the 14oz cans, as along with the E24, I need to recharge my '92 Spider.
Dean
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'08 350Z

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Post by hornhospital »

Be careful buying and using the R12 from eBay or elsewhere. ALL of it is captured and rebottled stuff, and there's no guarantee it's been filtered or cleaned in any way. You may be pumping in 100% R12, or a witches brew of other contaminants plus R12. Word to the wise.
Ken Kanne
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dwcains
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Post by dwcains »

Good advice. I thought about buying one of those 25lb bulk cylinders, most of which were partially used/filled, but I had that same fear. All the stuff I bought is in untapped original 14oz cans.
Dean
Lutz, FL

'85 635 CSi Euro #9402254
'87 Spider Veloce
'92 Spider Veloce
'08 350Z

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jacko
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Post by jacko »

Looks like the 7 piston compressors can be had with the same mounting as the old 5 series ones!
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TN_M6
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Post by TN_M6 »

This is helpful stuff and since this post was way up it saved me some searching on the topic. I am diagnosing the A/C on my M6. The dual system is complicated and my fear is the rear x-valve is not working properly. My pressures are a bit low on high side and a bit high on low side. Cool in front but now warm from the rear. Used to be cool in front and freezing in the rear. I've had the car about 8 years and it's gone slowly downhill in performance to the point it's now unacceptable in the 90+ weather 90+ humidity.

Looks like I'll be doing some more troubleshooting and digging around soon.

For simplicity I will either source R12 (probably not economical) or just convert and use HC-12a. The HC-12a is the only reasonable way to even consider keeping the AC functional in a car like my 265+ k mile 535 or the 305+ k mile 91 325 we had and a friend's son now drives. Both had minor leaks and in the case of both cars it would cost more to fix 'properly' than the car is worth. Both cooled respectfully well at normal cruising without any major changes. The 325 did need a new H type x-valve which brings me back to the M6.

EVERY e30 I've been around has had a leaking H valve as the source of A/C system failure. A friend's e46 has a leaker right now. I wonder if the M6 has a similarly problematic rear valve? And when I went on BMWfans.info it did not show the rear system for my vin however it's all there for the 89 635 csi general listing. I assume the parts are in fact the same if someone knows that answer. I'll explore the rear, maybe, hopefully, it's not much more than a bad connection at the electric valve but the listing shows that valve NLA.

Living in a smaller town without all the big city traffic and associated problems I'm not so afraid of the HC thing. I'm also not a smoker. I would not use it if I were since yes there is a lot of refrigerant and pipes inside the cabin so DaHose's concern about the HC is warranted. While the big 6 series dual A/C system uses a lot more refrigerant than others like e30 or e28, at 1/3 weight roughly it's not really all that much, still < 2 lbs.

Again, nice the topic was back up near the top and relevant to me. I just hope I'm not in for a big overhaul of my A/C.
Last edited by TN_M6 on Tue Jul 14, 2015 6:12 pm, edited 1 time in total.
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Post by Da_Hose »

That is an odd condition TN-M6. It does sound like your rear x-valve has issues.

I have seen some "fishy" stuff as of late, with people posting ebay ads for refrigerant and asking you to fill out a form confirming that you will NOT install yourself, but resell it out to someone with appropriate licensing. Maybe this is a loophole people figured out and that is what is making R12 cheap again. If you go R12, but enough for at least two complete fills. You will likely need to top off over time and if you have not replaced all your hoses, any work will obviously lead to needing more refrigerant.

Since my system is already R134 and I have fresh barrier hoses, I have no need to revert back to R12. Although looking for genuine R12, I see it still going for about $40 a can. Still, that is a far cry less than the cost of conversion. If anyone has not yet converted, then I agree. Get some R12 and be done with it.

Jacko - The 7 piston should put slightly more load on the engine, but will not struggle to keep up with the volume needed to supply both exchangers. It will definitely be more efficient that the original pump. Matter of fact, it might even make up for inefficiency in the condenser via greater volume.

Jose
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Post by dwcains »

Da_Hose wrote: I have seen some "fishy" stuff as of late, with people posting ebay ads for refrigerant and asking you to fill out a form confirming that you will NOT install yourself, but resell it out to someone with appropriate licensing. Maybe this is a loophole people figured out and that is what is making R12 cheap again.

Jose
That does seem to be the scheme, but I've purchased a bunch in the past few months (3 different sellers), and no one has asked me for a license or signature. Here are the brands I've been getting:

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Dean
Lutz, FL

'85 635 CSi Euro #9402254
'87 Spider Veloce
'92 Spider Veloce
'08 350Z

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