Hello,
My a/c was working fine before but, I've let my 83 300SD sit since February and it needed a recharge. I tried to put some 134a in it and it seems like there is a leak in the compressor - you will see all kinds of gas come out of the compressor through the belt that turns it when you try to recharge it and you can hear it hissing out. When I first turned my A/C on after 5 months it actually caused the car to stall. Is the compressor dead does it need O-rings?
thanks,
Tom Martin who is prepare to be called an idiot.

Tom, you need to install a new compressor on it. Don't mess around with a rebuilt, go ahead and purchase a new one.

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Jim

Try to find out if the seal in the replacement compressor is compatible with the oil used with A 134. When shopping for seal kits I am often asked which refrigerant is being used. The seals in some compressors cannot deal with A-134 Oils.

the odd thing is it is fine with the compressor off when I turn it on it will start to leak. Where is the best place to get a new compressor?
Thanks,
Tom Martin

I have been successful purchasing from a local automotive a/c parts supply house here in town. Try to find the same type of place where all they sell is automotive a/c supplies.

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Jim

Yes, you most definitely need a new compressor and a new one, but it doesn't stop there. After a catastrophic failure to the point of compressor lock up, you must break all connections and THOROUGHLY flush each line and component, then flush those components, then flush again. Flush, flush, flush........... It also wouldn't hurt to add a suction side filter.

The reason for all this is that upon internal compressor failure, bits and pieces are scattered throughout the system and if they are not removed they will destroy the new compressor in very short order.

In addition, you will need to replace the receiver/dryer and of course all o-rings.

On a system that has been converted to 134 you never know how it's been converted. An improperly converted system is destined for compressor failure such as this. In come cases even a properly converted system will result in your problem. The R4 compressor that is on your car is not among the most robust.

Some cars convert pretty well and some don't. Yours was not a good candidate. R12 prices are coming down. If the car were mine, since you have to thoroughly flush, replace the drier and compressor, I would put in mineral oil and R12 and reverse convert.

Good luck,

Soooooo, when the compressor fails to the point of lock up is when it puts the metal in the system. Glad to know that. If this is the case then don't forget the expansion valve.

I'm not too sure you would be able to thoroughly clean it all the way out. What do you think Larry? It has some pretty small openings in there and some intricate internal workings.

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Jim

To flush a system properly all forms of restriction must be removed, which absolutely means the expansion valve. Think of the word "Flush" think of violence. The more violent the flush the more likely you did something.

Personally I don't think there are many DIYers that can achieve a usefull flush. THe technique requires more violence than is usually used. The form of flush needs to be anticipated for different areas of the system. I wouldn't flush an evaporator unless I had a very volitile flush (one with a boiling point close to room temp would be nice - atleast the remainder could be boiled off during an extended evacuation). Trying to flush through an expansion valve would be useless if not disasterous. The little bit of flush solvent that made it through would totally stay in the evaporator without violence.

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Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician

Wouldn't it probably be best just to plan on replacing the expansion valve if it is the "H" design. I know you can't properly flush it out.

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Jim

I never reuse an expansion valve. They are the cheapest piece in the whole system and they are the refrigeration brain.

I can't see much need to flush an expansion valve. The block type valves are totally exposed when off the system. Anything in them is easily visable.

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Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician

The compressor seems to actually work now - it just leaks for whatever reason. There is a definate difference in pressure from on the low side from when it is on and when it is not. How much can I expect to be charged for a compressor flushing and refilling. The car has been R134a since I believe 1997 or 1998
Thanks,
Tom Martin