A/C Compressor Leak

[rminc]

Hey everyone

I was checking my oil yesterday and I noticed some green liquid on the front of the A/C compressor. It was literally a drop. 

I'm not too familiar with A/C systems, but it must be a leak of what looks like tracing dye? If anyone can help out with the best way to go about getting this fixed, as I am not sure where to start. 

I've heard these are a pain to repair and replace and my A/C is working perfectly, blowing cold air as it should. 

I've attached a photo with an arrow pinpointing the spot. Car is an 1987 911. 

[Peter M]

The front seals fail on these compressors causing the oil leak.  Once it gets worse you will notice a line of oil spray above the inside face of the pulley on the inside of the engine lid.

Fortunately these Denso compressors are simple, generally very robust and have been used in many makes of car with the seals being easy and cheap to replace if you are a bit hands on.

I've found the Century Air in Arizona to be helpful with a good website shop (also on eBay) and some useful Youtube videos

CENTURY AUTO AIR CONDITIONING  and Denso 10P-Series Compressors (shopcenturyautoair.com)

On the rear cover of the compressor will be model number that you need to know to order parts.  My memory is the 3.2's use a 10P15C but I do tend towards being hazy nowadays.....

Likely cost of a full seals kit with lid seal protector for the shaft assembly is about 30bucks USD and a container of Denso ND8 or equivalent oil which is about 50bucks AUD from eBay.  Plus the regas cost of course.

I foolishly replaced my first leaking Denso compressor with a new unit not knowing much about them.  Now after having two other cars with faulty units I've realised they are much cheaper and very easy to repair myself! I've also changed to using HyChill Minus 30 refrigerant because it performs better than R134a and I can do it myself.

Pity you don't live closer as we would have had it off the car and disassembled on the bench by now!

[Mike-S]

Just call Steve Varasso in Ringwood, SV Autoelectrical. He’ll sort it in no time.

[rminc]

12 hours ago, Peter M said:

The front seals fail on these compressors causing the oil leak.  Once it gets worse you will notice a line of oil spray above the inside face of the pulley on the inside of the engine lid.

Fortunately these Denso compressors are simple, generally very robust and have been used in many makes of car with the seals being easy and cheap to replace if you are a bit hands on.

I've found the Century Air in Arizona to be helpful with a good website shop (also on eBay) and some useful Youtube videos

CENTURY AUTO AIR CONDITIONING  and Denso 10P-Series Compressors (shopcenturyautoair.com)

On the rear cover of the compressor will be model number that you need to know to order parts.  My memory is the 3.2's use a 10P15C but I do tend towards being hazy nowadays.....

Likely cost of a full seals kit with lid seal protector for the shaft assembly is about 30bucks USD and a container of Denso ND8 or equivalent oil which is about 50bucks AUD from eBay.  Plus the regas cost of course.

I foolishly replaced my first leaking Denso compressor with a new unit not knowing much about them.  Now after having two other cars with faulty units I've realised they are much cheaper and very easy to repair myself! I've also changed to using HyChill Minus 30 refrigerant because it performs better than R134a and I can do it myself.

Pity you don't live closer as we would have had it off the car and disassembled on the bench by now!

Thanks for the reply Peter. I remember reading a while ago that these compressors were designed for an older gas that we no longer have and don't work as well with the R134a.

There is a place up in QLD that converts some of the inner components to run better on the R134a. That's what I was told at my last service. Is it worth doing that? 

Also, how hard is it to remove the compressor and gas from the car? It looks like 8 bolts and a Phillips head for the wire, which I doubt will come out easily. 

[Peter M]

Rmic,

I've never heard of anyone converting compressors but some talk about improvements coming from changing Tx valves in the evaporator when changing gas types.  (The Tx valve is where the liquid refrigerant is expanded into a gas that then cools the evaporator). I've yet to see anyone post data to support changing Tx valves however.

Also when converting from R12 to R134a results in the system running at higher pressure and it is customary to install a trinary pressure switch that will cut power to the compressor if the system is under pressure (risk of compressor being under lubricated and at risk of seizing as the refrigerant carries the oil) or overpressure (risk of bursting hoses.).

I don't know when Porsche went from R12 (my '85 3.2 was originally) to R134a (that my '88 3.2 had) so I don't know what refrigerant your car came with however I think its safe to assume it currently has R134a and from what you have said you are happy with its performance.

What I suggest you do:

1. Check if you have a trinary switch installed for safety sake,
2. Have a auto AC specialist evacuate the system as legally required when working with R134a refrigerants
3. Disconnect the two hose connections from the compressor, remove the 3 long mounting bolts from the top of the compressor and unclip the pulley clutch connection.  Also unscrew the pressure switch located near the hose connections. The compressor will then lift off.  You'll then see how the belt tensioning mechanism works underneath.  Tape up the hose ends and remove the drive belt so you can drive the car while waiting for parts.
4. Order a seals kit after confirming your compressor model on the back plate.  Check the pulley turns smoothly.
5. Using your new found knowledge from Youtube install the seals kit into the compressor.   Assuming the compressor hasn't been starved of oil, the existing bearings and pistons and bores should be fine. 
6. Reinstall the compressor including correctly tensioning the drive belt.
7. Have your AC specialist regas with R134a and add the appropriate amount of oil to replace that lost in the compressor rebuild.

Done!

If you decide this is too hard and you want to simply replace the compressor, it's worth hunting around as the prices vary wildly.  Also beware that many units advertised are remanufactured which in itself isn't a concern, just when you are comparing prices with new units.

Good luck!

 

[Coastr]

I don’t think the compressors care what gas is in them, but the type of oil makes a difference.  There was a lot of fud thrown around back in the day around r134 conversions, most of which can be ignored.  The advice you have here is good - new seals, new oil, regas and good to go.  If that’s the original unit I would stick with it rather than replace with a knockoff.

[autojack]

If you want to DIY the seal replacement, check out these instructions: https://www.pelicanparts.com/techarticles/911_Nippondenso_rebuild/911_Nippondenso_rebuild.htm

I followed these and everything was good except I put the nose seal in backwards and it failed after a few hours of running. So, don't do that.

[Peter M]

9 hours ago, autojack said:

mverything was good except I put the nose seal in backwards and it failed after a few hours of running. So, don't do that.

Auto, you are not alone in having done that once!🙄

 

Remember kids, seal lips to the inside!

[rminc]

I had a better look at my unit today and it looks like it's a replacement unit and not OEM. I've attached some photos @Peter M

The weaping of green oil is around the nut in the photo I've attached. Could it be something simple as tightening the bolt? I have no idea when it comes to A/C units. 

[Peter M]

Unfortunately the nut at the front just holds the front pulley clutch onto the shaft and is unrelated to the leak.

Nippon Air Parts is/was a Denso dealer in Mitcham Victoria that looks like it may have closed down now. 

So it's still the correct Denso 10P15C compressor, it just looks like it has been rebuilt previously based on the sticker replacing the usual Denso foil sticker that is normally located there.

[rminc]

19 hours ago, Peter M said:

Unfortunately the nut at the front just holds the front pulley clutch onto the shaft and is unrelated to the leak.

Nippon Air Parts is/was a Denso dealer in Mitcham Victoria that looks like it may have closed down now. 

So it's still the correct Denso 10P15C compressor, it just looks like it has been rebuilt previously based on the sticker replacing the usual Denso foil sticker that is normally located there.

Thanks Peter. Makes sense. 

[911]

Mine has never worked. I just removed the belt.

Does anyone know where you can source an OEM one. Not a rebuilt or remanufactured? I looked months ago. Could not find anything at all. 

[Peter M]

1 hour ago, wangan said:

Mine has never worked. I just removed the belt.

Does anyone know where you can source an OEM one. Not a rebuilt or remanufactured? I looked months ago. Could not find anything at all. 

Wangan,

The odds are that the compressor is fine and the reason why it doesn't turn is that there is insufficient refrigerant pressure.  The system has a low pressure switch to protect the compressor from insufficient oil (that is carried in the refrigerant).  An easy test is to temporarily jump the pressure switch contacts to see if it turns then.

However, if you do this, double check the front condenser fan motor turns along with the evaporator fan motor.  If the front condenser motor is seized it will cause a couple metres of wire in the frunk to burn so please take care.  Also good time to add a fuse to this circuit.  The evaporator fan will probably still work but the squeaking from the dry bearings will drive you mad!

[911]

25 minutes ago, Peter M said:

Wangan,

The odds are that the compressor is fine and the reason why it doesn't turn is that there is insufficient refrigerant pressure.  The system has a low pressure switch to protect the compressor from insufficient oil (that is carried in the refrigerant).  An easy test is to temporarily jump the pressure switch contacts to see if it turns then.

However, if you do this, double check the front condenser fan motor turns along with the evaporator fan motor.  If the front condenser motor is seized it will cause a couple metres of wire in the frunk to burn so please take care.  Also good time to add a fuse to this circuit.  The evaporator fan will probably still work but the squeaking from the dry bearings will drive you mad!

I should have gone into a bit more detail. It was regassed, but failed to hold pressure. It would keep leaking and I've read that the seal replacements aren't too crash hot, so it put me off. 

I've been looking to buy a new one for a while to replace it, but haven't been able to find one unfortunately. Most places are only reconditioned, or remanufactured. 

[Peter M]

eBay has new ones if your search "Denso 471-0124" for about $700 onwards.  Lots of reconditioned ones as well I agree.

I disagree that "seal replacements aren't too crash hot" provided the work is done correctly including replacing the case o-rings if they get disturbed.  A set of seals (<$100) plus a bit of labour will have it done.

So I wouldn't be concerned about getting a reconditioned unit from a reputable supplier.

[911]

11 minutes ago, Peter M said:

eBay has new ones if your search "Denso 471-0124" for about $700 onwards.  Lots of reconditioned ones as well I agree.

I disagree that "seal replacements aren't too crash hot" provided the work is done correctly including replacing the case o-rings if they get disturbed.  A set of seals (<$100) plus a bit of labour will have it done.

So I wouldn't be concerned about getting a reconditioned unit from a reputable supplier.

I had a seal replacement years ago with my old car. The problem I found was that the seal on the shaft failed after less than a year. I have never had much luck with rebuilding a/c compressors. You can crack the carbon, have a slightly pitted shaft and then the question is not if, but when. 

Reconditioned would not be too bad if are provided with a warranty. The issue is most of the ones for sale are in the states. The one you mention for $700, I'd be banking on it being a repro, or reconditioned unit. I rememeber seeing some listed as 'new', but once I messaged the seller, I was advised that they were repro. I wasn't able to find a single new one when I was looking. 

[rminc]

I don't think you can buy new ones anymore. I've been trying to find one with no luck. All remanufactured or refurbished. 

I guess it makes sense. It's not something you can have as new old stock, seeing as the seals and oil would eventually leak without being used. 

Can anyone recommend going for a remanufactured vs refurbished? Is there any difference? Or just buy whatever is cheaper? 

[Peter M]

14 hours ago, rminc said:

Can anyone recommend going for a remanufactured vs refurbished? Is there any difference? Or just buy whatever is cheaper? 

In this case the terms mean the same so I wouldn't sweat it.  I'd look at price, Ebay feedback and who did the reconditioning and make a decision on that.

[rminc]

On 14/08/2022 at 20:51, wangan said:

I had a seal replacement years ago with my old car. The problem I found was that the seal on the shaft failed after less than a year. I have never had much luck with rebuilding a/c compressors. You can crack the carbon, have a slightly pitted shaft and then the question is not if, but when. 

Reconditioned would not be too bad if are provided with a warranty. The issue is most of the ones for sale are in the states. The one you mention for $700, I'd be banking on it being a repro, or reconditioned unit. I rememeber seeing some listed as 'new', but once I messaged the seller, I was advised that they were repro. I wasn't able to find a single new one when I was looking. 

I don't think you can actually buy a new unit anymore. Would make sense I guess. They would have stopped making them years ago and any NOS would have probably leaked the oil that was in the unit by now. 

I'm just going to keep an eye on the leak and see if a cheap reconditioned one comes up.