| Author | Message | ||
     Jean-Pierre 'JP' Hilbert Experienced User Username: jphilbert Post Number: 13 Registered: 9-2013 |
Finally the seal kit for my R143a Harrison A6 compressor arrived, together with an UV detection lamp, which confirms that the overpressure valve (slightly below and between the HP and LP fittings) leaks in abundance. Now while I'm at it, I would want to know whether it is a good idea to change the oil inside the compressor, and secondly, if PAG or esther oil should be used (I found conflicting info in the manuals and internet). Any thoughts? | ||
| Brian Vogel Grand Master Username: guyslp Post Number: 1114 Registered: 6-2009 |
JP, I can't remember what year/model car you're dealing with or whether the R143a was OEM or converted. I seem to recall you having several cars that "cross AC refrigerant eras" but I can't be certain of that. I'm sure Bob uk will chime in, but I've always been told that R134a systems that came that way use PAG (and then you need to check the viscosity for your compressor), but ester oil is used for systems that were converted from R12 to R134a. The best "quick reference" chart I've found for this is here and has a "flip-flop" button if your car originally came with R12 rather than R134a. There's a scrolling banner at the top of the page making it quite clear which table you're looking at. Brian | ||
| Jean-Pierre 'JP' Hilbert Experienced User Username: jphilbert Post Number: 15 Registered: 9-2013 |
Brian, This car came with R12 standard, its an 85, shipped DEC 84. I would be interested to know whether the A6 is the original one to not. There is a sticker on it saying it got metric threads...great to see after I just got an inch poler from the US. What you don't have in your eyes you must have in your wallet as we say here... BTW I only have this one P-M-C, unlike some other folks I visited in Dubai recently ))))...Omar, any thoughts on above discuss? | ||
| Bob uk Unregistered guest Posted From: 94.197.122.72 |
My compressor is GM Frigidaire Delco Remy A6. Well known for being a good reliable robust compressor. subject to servicing and abuse of course. Keep posting on the rebuild of the compressor because my system needs doing and I found a bit of oil under the pully which could be oil leaking fRom the seal. Also some fridge oils already have dye in them. Ask the supplier. Photos would be nice. (Message approved by david_gore) | ||
| Bob uk Unregistered guest Posted From: 94.197.122.71 |
PAO oil is formulated for both 12 And 134a. Which means that when converting to 134 from 12 pao won't react with seals or any mineral 525 oil lurking in the system. Pag is hydroscopic like brake dot and is ester and glycol like dot. This does not mix with 525 and forms gloop. If using pag in a R12 system a flush is required. Consult the shop that is going to charge the system. If you are going to recharge the system with diy cans then use scales to get the weight right. The system must be pulled down to 29.5 inhg or more. I like to see 1 hour with at least 28 inches with system shut off from the vacuum pump. Also good is a bit of nitrogen which likes water. I cannot stress the timportance of making sure the system is clean inside. New drier is a must. The old drier can allow desicant to escape around the system. If you haven't got a vacuum pump that will pull 29.5 then you must get a shop to do the charging bit. I have heard people say that 27 or even weaker vacuum will do. The science fact says that the water won't boil off and the system will have water in it. So anything less than a proper job is no job at all. Don't forget to check the condenser for dead bugs in the fins. Also the charge weight is different for 134 versus 12. My jeep is 134 and it works fine it is linked to the demister which works very fast and exercises the ac in the winter. (Message approved by david_gore) | ||
| Paul Yorke Grand Master Username: paul_yorke Post Number: 1327 Registered: 6-2006 |
Definitely go for a flush and new dryer, with new oil. I'd also suggest that if the compressor is working well and it's just the relief valve leaking, just replace that. Have you tried the puller yet? I've got the feeling that it may just be the bolt holes etc that are metric. | ||
| Jean-Pierre 'JP' Hilbert Experienced User Username: jphilbert Post Number: 17 Registered: 9-2013 |
Yepp, the most expensive dryer I ever bought is here on my shelf. and yes, I'll make a detailed post once I have the time to actually perform the manoeuvre, and that's where I will see if the puller fits ))). There are some videos on youtube https://www.youtube.com/watch?v=0c7QXLNqgBU&list=UU2DGJ55gjwbEXgWNf1_OIZQ For everybody's benefit, I also found those instructions : http://kasplutt.dlinkddns.com/Cad/HarrisonA6/ | ||
| Omar M. Shams Grand Master Username: omar Post Number: 440 Registered: 4-2009 |
Dear Jean-Pierre, Sorry for not responding earlier - I go through phases of being hugely busy and then back again to some form of normality. The oils used in different countries may not be the same as the ones we have here in Dubai. I don't know enough about the proprietary brands to know which is is best. Having said that, I don't think there is much of a big deal as long as the following happens: you use the appropriate type of oil for the 134 gas you are using (note not all 134s are the same). You ensure the internals of every component is free of dust and debris. You may have to replace hoses if you are not sure of their cleanliness. You put a new receiver drier. you pressurise the system with nitrogen and vent all the air out. you vacuum the system as much as you can. you introduce only one type of 134a gas. you watch the sight glass on the reciever drier for bubbles and stop putting in gas just before the bubbles stop flowing. Now you will have ice cold ac like you experienced when I froze your backside in my 79 Wraith II. Please remember that you must only ever introduce gas into the system - never liquid. some garages invert the gas bottle and let liquid 134a enter the system when the compressor is running. This is a major major major no-no. Don't be tempted to do this as liquid is not compressible and something has to pop. | ||
| Bob uk Unregistered guest Posted From: 94.197.122.80 |
Further to already posted. The hoses will have 525 oil forced into them which helps sealing. Flushing doesn't remove it. So even after flushing using PAG oil could cause gloop. As Paul says if only the thingy is leaking then don't fix what isn't broke. It is ok to use compressed air to tests for leaks. After all the system will have been open to atmosphere while repairing. The old standby of soapy water to find leaks is still a good way. Pressure to say 60psi on air don't run the compressor. Leave for a few hours if the pressure is still 60 then the system is good. The vacuum way only uses 14.7 psi and it's trying to get in instead of trying to get out. Note if the compressor seal is leaking and the system has not been used for months or years, the seal maybe leaking because its dry. So if the seal is leaking take compressor off and fit the oil turn the compressor ten times by hand refit and try again. If it still leaks then rebuild. Also the evaporator box has a drain for the water dehumidified from the evaporator. It is somewhere over near the bell housing. It looks like a pipe end with a slit. Squeeze it so it opens, poke it to make sure it's clear. Everybody forgets these until stinky Water and wet carpets happen. (Message approved by david_gore) | ||
| Jean-Pierre 'JP' Hilbert Experienced User Username: jphilbert Post Number: 19 Registered: 9-2013 |
I think I need to go the full monty, that is, replace every seal in the system. I got my ducks aligned for that, got a whole shoecartonbox full of the things I need for total a/c rebuild. It is my strong belief that everything remotely similar to rubber lives on borrowed time in a 1985 car. I had issues with almost every rubber part on this car: brake hoses, hydraulic hoses, suspension bushes, subframe mounts, steering linkage donut, steering rack, engine mounts, levelling valves, shock absorbers, gearbox in &out seal, oilcan gasket, top&bottom radiator hoses, gearbox radiator hoses, brake pump seals, front windshield seal and now the side glass seals. Hence I severely question the durability of the a/c rubberware, so I will gladly disobey Bob's recommendation ;) but I appreciate your otherwise very valid input! Omar, many thanks too for the step-by-step description of the procedure (I'm still recovering from the cold you exposed me too, but it left me impressed that it is indeed possible to fine-tune the a/c so that one can actually hang meat in our cars))))) | ||
| Bob uk Unregistered guest Posted From: 94.197.122.87 |
In that case having all the bits and the motivation go for it. My 1974 has no rubber issues and apart from one engine mounting I have got away cheaply on the rubber front. Do take care lifting off the compressor, easy to strain yer back. Use assistance cover wing. Apart from the weight of the compressor air con is quite pleasant to work on. And on RRs the compressor is easy to access some are fitted low down and covered in muck. My jeep is like that. The Shadow one ws manual has a strip down guide on the A6. Plus the rebuild is on YouTube. (Message approved by david_gore) | ||
| Daniel Diewerge Experienced User Username: didi13109 Post Number: 43 Registered: 11-2009 |
Salut Jemp, please keep in mind that a R134a system runs at a higher system pressure than a R12 system, the R12 valve will trigger if the system is not correctley filled with R134. The correct way is to mesure the low and high side while filling the system, just inserting a certain amount of R134a based on weight is not sufficient. Your system has already been converted to R134a in the past by a professional in the US. Since he replaced all the hoses with the correct barrier type hose and also changed the drier, I suppose that he did a proper job and also converted to PAG oil. Ester oil is not the first choice for AC systems |
