Air Conditioning Compressor siezures. B280E (R12) (Sanden SD709 compressor)

[pettaw]

Sorry if this is too little too late but I bet when you seized you first compressor debris got scattered throughout the system which has basically clogged it up, and now oil isn't migrating through properly, seizing compressor after compressor. For instance did you pull your orifice tube out and check the inlet screen for debris?

If the crankcase for the compressor holds about 200 mls of oil you should be adding 200mls to the compressor and about 100 mls into the accumulator for the rest of the system.

Peter, those 'magic in a can' solutions with dye, oil, powerboost, sealer, the kitchen sink etc are what many people call 'death kits' The oil, and dye are great, but the powerboost is snake oil and the leak sealer will stop up everything apart from the leaks it was designed to stop. Not an expert myself, but according to those that know, once leak sealer has been introduced to the system can very easily bung up the entire system meaning everything has to be replaced.

I could be wrong, but I have yet to see a all in one product that just contained an oil charge, dye and R134a.

Yes I think some may have got through the system, but all the damage has been to the crankcase (Thrown rod) or drive end bearing siezed. The 220cc of oil was from the accumulator. When I washed out the accumulator there was a little black powder and some very fine flakes of metal, but these were well settled in the bottom. The compressor was lightly smeared with oil inside, but the ball in the centre of the swashplate was dry. Clearly a little more oil in the system would have made it survivable. My engineer checked for obstructions such as ice crystals as we charged the system so I think it's OK.
I could show a pic but the digicam is inaccessable.
Next time I go for a chare up I'll dip tha crankcase and make sure ther is free oil in the bottom.
I'm not a refrigeration engineer but I'm pretty mechanical.
The refrigerant is R413A and the lube, Shell Clavus.
Hope this sharpens the picture a bit.

[pettaw]

Shell Clavus is a mineral oil, and not miscible with R134a, which means the lubrication won't be able to flow with the refrigerant round the system, lubricating the compressor. you need to get that out and get some Ester oil in there that WILL do the job. That's if you did a typo and you meant R134a.

There is also a refrigerant called R413a which is a R134a blend designed as a drop-in replacement for R12. The trouble is its mostly R134a with a few additives to carry the mineral oil round, so it will still leak out from the seals the same as the R134a, meaning you've no knowing whats in there after a couple of months, and topping off is not possible, you have to vac and start again everytime. If you've gone to the trouble of changing accumulators and compressors and flushing then you might as well change the 2 quid orifice tube and convert to R134a.

BTW, I'm not an A/C expert either, just passing on info gathered through doing research and working on my own car.

errrrrm
It is R413A. I think you typo'd with your typo question.
Where does the orifice tube hide then ?.
If I change the tube can I then run with straight R134A and Ester oil ?
Paul.

[pettaw]

You'd need to change the o-tube, and accumulator and put R134a fittings on. I'd also consider a system flush to get all the mineral oil out but that's not mandatory. I THINK the O-tube should be in the condensor outlet, but some are in the evap inlet.

I would say, as you're as gassed up and running to monitor and see how it goes and then when the system needs regassing to consider a changeover.

Its easy to do a typo and press the keys in the wrong order, I've done it myself often enough, and you press 'post' and oops did I mistrype something? :) Unusual to go to all that trouble of pulling everything apart and then to go back to a blend refrigerant.

I would look in the website 700/900 FAQ for what other 700 series owners have done to convert theirs and see how well or badly they're cooling. No harm in getting as much info as poss before starting ;)

Hope that helps.

Agree.These forums are hugely beneficial when doing anything beyond the Haynes.
That's most things.
Paul.

All sorted then Peter.
Thanks for your help. I'm running R413A refrigerant with Shell Clavus lube and it all seems to have been pukker for the last week.
Smashin'
Thanks again,
Paul.

Petaw
"Sorry if this is too little too late but I bet when you seized you first compressor debris got scattered throughout the system which has basically clogged it up, and now oil isn't migrating through properly, seizing compressor after compressor. For instance did you pull your orifice tube out and check the inlet screen for debris?"
Well you were right on the money there !
I've now gone and blown a hole in the bottom of the Condenser,(£115) busted the cooled refrigerant to Evaporator line (£45), gotta put in a new Accumulator (£55).
All this because, I suspect, the Orifice tube was bunged up with a load of black crud, causing the loss of flow and subsequent overpressure which caused the Condenser failure. Attendant with the overpressure was the associated high temp that caused the last compresssor failure.
I only found the orifice tube cos I pulled the return pipe off once I had broken the Condenser end off whilst removing the leaking Condenser.
This is all because I didn't get the job done right in the first, second or third place.
Oh well. Live and learn,
At least Peter's compressor hasn't come to harm.
Paul.