Automotive Air Conditioning Information Forum

Background:

I’ve spent several months building my knowledge base and researching what others have done to convert the 4th gen Civic to use the Sanden 4993 compressor (also used in the 5th and 6th gen Civics). I won’t go over most of it as it can be found at two main links (for those interested), and my remaining questions probably fit better here than on either of these:

https://honda-tech.com/forums/honda-crx ... x-3214534/

That thread is huge, with 138 posts from December 2014 to July 2022.

The other has many of the same people filling in details not in the first forum: https://www.crxcommunity.com/threads/cu ... or.166226/

It’s almost as large, (117 posts) from April 2015 to November 2021.

I’m a retired engineer (electrical) with too many DIY projects. I don’t do things without feeling comfortable that I understand the nature of the problem and what I am doing. That can drag out projects well beyond what other people would tolerate. I sometimes know when to resist doing it all and hire out what I choose so I can get things done before I die or my S.O. puts a stop to it!

I already have the new Sanden 4993 (Manufactured about a year ago), and have pulled the old compressor (Sanden TR-70) which supposedly failed. I say supposedly because my local mechanic who upgraded the system to R134a from R-12 (and who I generally trust) may have gotten the diagnosis wrong, but we are past that.

The plan is a complete rebuild split between myself, a traveling mechanic friend (wintering here for a few more weeks) to do the physically hardest work beyond my strength and tool set, and a local business (yet to be chosen) to do evacuation / leak testing and charging, so I have a place to take it for future service, which I don’t want to handle.

Main Issue: My mechanic friend will mount the new compressor before he leaves (He won’t be back until next fall.) That job is easy for him, but the plan is to mount it with the factory supplied shipping pads that seal in the SP-10 oil that Sanden put in during manufacture. I can then handle the rest of the system replacement including custom suction and discharge hoses myself before bringing it in for evacuation / leak testing and charging.

The oil charge spec is 130 +20/-0 cc. See: https://www.sanden.com/productlibrary/s ... s/4993.pdf

From: https://www.sanden.com/objects/Compress ... ctions.pdf

“New Sanden compressors are shipped with all the oil required for a normal OEM system for which they were intended. In most cases no additional oil should be added. For R-134a A/C systems the original Sanden PAG oil shipped in the new Sanden compressor is the best lubricant for compressor durability.”
“For a few rare cases such as very large A/C systems with long hoses which use more than 4 pounds of refrigerant, additional Sanden oil may be required. Consult the OEM manufacturer’s specification for oil and refrigerant quantities.”

So question one is: Is it reasonable to assume no oil will need to be removed from the compressor as delivered by Sanden? I don’t want to have to remove the compressor again for any reason after my mechanic friend mounts it. It would be difficult if not impossible to drain oil with the compressor mounted. The below attachments suggest we are in the ballpark if not slightly overfilled, however note the amount expected to be left in the compressor is higher for ‘90 than ‘94, which appears to be due to the expected amounts in the condenser plus evaporator 40cc vs 65cc. I will be replacing those with aftermarket 1990 parts, so I would expect ~40 cc, not 65cc. I might expect that would bring the compressor oil up by ~25cc.
I really have no idea how critical these oil distributions are. Any comments from those with lots of experience are appreciated.

The following info was taken from 1990 and 1994 Civic manuals. I didn’t bother to round my cc to oz conversions. I know it’s ridiculous!!!

*the 1990 used either one of two compressors Sanden or Matsushita


I have some other questions but they are not show stoppers as far as derailing my schedule is concerned, so I will post those after I receive comments on this main question.

Thanks,
Jim

Well, you have certainly researched this thoroughly which would be expected of an engineer, and you are to be praised for this. And BTW the 130 cc of oil calculated out to just about 4.4 oz (fluid oz, some posters do not understand that fluid oz are different than postage meter oz). Most of us think more in terms of oz. (fluid oz measure volume, the other oz measure weight. Very different). Your 130cc should be just about right.

Now my next statement will trigger a 'gulp' on your part.
The amount of oil in an automotive AC system is almost a crapshoot beyond the initial factory install. Of course, by the time you are done, you will indeed have a factory-level install.

Once you are past that starting point, there is no way to know how much oil is in there unless you flush the entire system and start over. I say this because we have posters replacing only select components of the system. (we do have suggested amounts for them) Oil is the most indeterminate parameter that could ever be once you are past that original state. The precise amount of oil is immaterial. While this grates on your brain, realize that the system can accommodate small variations from the starting point. The suggestions we have for the ppl who are just replacing parts of a system are pure guesses based on experience. In no way are these amounts exact, yet it always seems to work. I have talked to refrigeration engineers (usually mechanical engineers) who marvel that a mobile system can work at all, they are used to dealing with static systems such as supermarket refrigeration.

Think if you will about an automotive AC system as a living thing. It needs to function at a variety of ambient temps, and the compressor to turn at a variety of RPMs. The amount of oil contained in each of the components is that which clings to the walls of the hoses and devices. That amount changes with the ambient temps. The amount of oil that is dissolved in the refrigerant changes with temperature, also. And of course most compressors have a sump.

On very large industrial compressors, an oil sight glass will be found on the crankcase...we have no such luxury.

You are lucky, and will be at the factory starting point, and the 4.4 oz will be fine.

As far as seeking a shop to evacuate and charge, I would strongly suggest locating a MACS certified shop. Our own JohnHere, a very knowledgeable consultant, is MACS certified. MACS stands for Mobile Air Climate Systems. One of these locations can be found by using the search feature on their website. This is the only certifying mobile AC entity in this country. This is very different than taking your car to a brakes shop to have AC done. For example, their vacuum pump has probably not had the oil changed since it was new 10 years ago, meaning the vacuum they will pull will be miserable. The better the vacuum, the better it works.

https://macsmobileairclimate.org/

Thanks tbirdtbird. That does relax me quite a bit, and I follow your explanation easily.

Sanden's statement re. the factory oil amount implies what you are saying. I could see that way too much oil could slug the compressor. Conversely, only the compressor needs the oil and some minimum level wouldn't be enough. That range can't be solved short of destructive testing or very accurate computer aided modeling of the whole system which I'm happy to not have to do! You mention the likelihood of a sump. The 4993 is a scroll compressor. Does that make it more or less likely that it has a sump?

Your other recommendations are well taken.

I'll probably post some other questions soon, but will give others a chance to weigh in before giving them the opportunity to have too much else to think about.

"You mention the likelihood of a sump. The 4993 is a scroll compressor. Does that make it more or less likely that it has a sump?"

Honestly I will leave that question to the other consultants because I do not know. I just mentioned that in passing, because it really doesn't matter.

Was the TR-70 a scroll?? I only ask because for some reason scrolls don't seem to hold up well in the mobile application. Of course they do famously in the residential application. Is there a non-scroll drop in available?

90efAACIF wrote: ↑Sat Mar 04, 2023 7:01 pm The 4993 is a scroll compressor. Does that make it more or less likely that it has a sump?

The Sanden 4993 scroll compressor doesn't have a sump in the same sense as, for example, a GM A6 compressor does. The A6 also has an oil pump, which the Sanden lacks. But according to one of the links you posted, the Sanden has a drain plug on the bottom, which in conjunction with the HP and LP ports, should allow for complete draining of the SP-10 oil that's in it now.

90efAACIF wrote: ↑Sat Mar 04, 2023 1:46 pm So question one is: Is it reasonable to assume no oil will need to be removed from the compressor as delivered by Sanden? I don’t want to have to remove the compressor again for any reason after my mechanic friend mounts it.

The data that I have for your '90 Civic specifies 31 ounces net weight of R-12 and 4.5 fluid ounces of Mineral Oil. The factory-fill oil in your Sanden is SP-10, which is the same as PAG-46. You also mentioned that the entire system is supposed to have 130 cc (4.4 ounces) in it, which closely approximates the specs I have.

If you want to keep all the oil in the compressor (which is the way the factory does it), I would drain the compressor completely on the bench, and then refill it with the specified amount of 4.5 ounces or 130 cc of fresh PAG-46 to ensure that it contains the right amount.

If you feel more comfortable distributing the oil throughout the system (called "oil balancing") instead of putting all of it into the compressor, I wouldn't be too concerned with what the tables say. I would simply add 1/2-ounce (or 15 cc rounded up) into the condenser, evaporator, and R/D, 3 ounces (or 85 cc) into the drained compressor, and call it done.

We can discuss charging the system with R-134a instead of R-12 a little later.

tbirdtbird wrote: Sat Mar 04, 2023 10:02 pm

Was the TR-70 a scroll?? I only ask because for some reason scrolls don't seem to hold up well in the mobile application. Of course they do famously in the residential application. Is there a non-scroll drop in available?

Yes, both the TR-70 and the 4993 are scrolls. No there isn't a non-scroll drop in replacement. I haven't heard reports of problems per-se with scrolls in mobile applications. Most of the problems I read were from re-manufactured TR-70s, not original Sandens. Sanden does warn about using re-manufactured replacements somewhere in their literature. Also, I have read that clones of the TR-70 (probably Chinese origin) weren't dependable. Sanden no longer makes the TR-70, which is why all the conversion interest is for the 4993 which was used by Honda for the 5th and 6th gen Civics.

JohnHere wrote: ↑Sat Mar 04, 2023 10:57 pm But according to one of the links you posted, the Sanden has a drain plug on the bottom, which in conjunction with the HP and LP ports, should allow for complete draining of the SP-10 oil that's in it now.

I don't see a drain plug on the compressor bottom, or anywhere on Sanden's spec drawing. There is a pressure relief valve on the back end, but I'm inclined to leave that alone. In Sanden's generic document at https://www.sanden.com/objects/Compress ... ctions.pdf, see: "Oil Amount for compressor swap with no internal compressor damage and no system flushing is required." mention of a drain plug and procedure is made, so some Sanden units have the plug but at least the 4993 doesn't.

If you want to keep all the oil in the compressor (which is the way the factory does it), I would drain the compressor completely on the bench, and then refill it with the specified amount of 4.5 ounces or 130 cc of fresh PAG-46 to ensure that it contains the right amount.

Yes I plan to keep it all in the compressor. I have heard others suggest draining / replacing the supplied oil, but i really don't see the need considering the following:

1) The supplied oil per Sanden's statement: “New Sanden compressors are shipped with all the oil required for a normal OEM system for which they were intended. In most cases no additional oil should be added."

2) The identification sticker on the compressor states "Oil Amt: 130cc". The spec drawing at https://www.sanden.com/productlibrary/s ... s/4993.pdf states: OIL CHARGE 130 +20 / -0 cc. I interpret that to mean the nominal charge at manufacture would be 130 +10cc comfortably set between the spec limits. If this were a re-manufactured or clone unit I would certainly question the oil amount in the unit. Based on 1) and 2) I don't see a real risk.

3) I know this is a genuine newly manufactured Sanden. While I didn't purchase it directly from Sanden, I verified the serial number with Sanden and they stated the manufacturing date as 3/31/2022. I would feel confident that the oil has not deteriorated in any meaningful way. Also in Sanden's Installation Instructions mentioned above, they reuse an amount of the oil drained from the new compressor to match the level drained from the old compressor.

Not having a drain plug is of no matter. I do not know where or how one would contact Sanden to see if a comp I had was genuine. Perhaps you could share that info.
From the Sanden website, here are the clues to genuine vs counterfeit: While we are at it, FYI, it is always a good idea to avoid any type of reman compressor, they do not hold up. Also, the products from 4-squeezins are to be avoided.

I am in such a habit of draining out the oil that came with the comp and installing new I don't even think about it, but at least then I am sure. I guess I could trust a genuine Sanden to be what it says.....but I would never trust another brand. It does involve rotating the crankshaft a dozen times to get it all out and then again to get it all back in (using fresh oil, of course).
JohnHere is correct, on the assembly line the comp already has all the oil needed. It would not be possible on the line for workmen/women to do the oil balancing method....too time consuming. We have a couple of industry-engineers on here who can vouch for this. (Detroit AC and GM Tech)

And you are correct, do not mess with the pressure relief valve

tbirdtbird wrote: ↑Sun Mar 05, 2023 10:33 pm I do not know where or how one would contact Sanden to see if a comp I had was genuine. Perhaps you could share that info.

I had called Sanden's main US office at 972-442-8400 when I was first researching the 4993 to talk to engineering with some questions. That led me on a wild goose chase for a bit. I found most of my answers on the honda-tech.com thread I mentioned and went ahead to purchase one on Ebay. After I received the compressor (an exceptional bargain considering the seller was claiming genuine Sanden and there was a 30 day free return period) I called Sanden back for verification with the serial number and was eventually forwarded to the right person, Janet Tokash, at 972-442-8921. She returned confirmation within a day, with the manufacturing date as well.

I've previously seen the clues to genuine vs counterfeit you've shown. I have only seen that on Sanden's Singapore website and apparently that may not apply to USA or Japanese made units. I say that because my unit was made in Japan, arrived in a box labeled Sanden International (USA) and the compressor label isn't green, but black and white, and has no special holographics / barcode like the Singapore units. It does have an alphanumeric code that is on the compressor label and a paper label on the box with that same code and accompanying barcode. In any case I'm very confident I have a genuine Sanden.

I did some more digging and it seems that
"Sanden supplies high quality, double end-capped (DEC) regulatory approved PAG (Polyalkylene Glycol) compressor oils "
This is interesting from the point of view of 'empty and then refill with fresh oil'. It is harder to get DEC oil than single end-capped oil, and DEC is much preferred. DEC will not absorb water.