I'm replacing the compressor and receiver/dryer on my 380sl, and was wondering whether it's really necessary to replace the expansion valve, too, as I haven't had one of those catastrophic failures that contaminates the system.

Obviously, I'd rather not replace the valve if the odds are good that it's OK, since it looks like a harder job than replacing the compressor.

Thanks in advance for the advice.

Bill

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Bill
1981 380sl

General thoughts are why not replace everything, including o rings and flushing lines, since new parts are likely to last longer than the old parts. If you don't you may be loosing freon to do repairs again later.

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85 300 SD ~ 115K
82 500 SEC Euro ??K
78 450SL 164K

If you are replacing the compressor due to leaking or rotational sensor problems rather than internal failure, you can leave the expansion valve alone. The only time it needs to be replaced is if it is leaking, not working properly or if the compressor has failed in a way that has strewn debris throughout the system.

Best of luck with it.

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2001 SLK 320 six speed manual
2014 Porsche Cayenne six speed manual

Annoy a Liberal, Read the Constitution

Thanks for the replies, though I guess people differ on this.

While I have your attention, though, I was wondering if you guys or anyone else here could answer any of the following questions for me:

Even though I didn't have a catastrophic AC failure, the clutch on my compressor has been chattering, and I can't tell if it's the original compressor or not. However, the PO converted it to 134 at some point. So I'm guessing that he probably had a problem with the compressor, and changed it, too.

In any case, as I've had the car for over 10 years now, I was thinking of replacing the compressor, which looks like a York, with a new AC Delco A6, given that Delco also makes these for GM. So I was wondering if anyone here knew whether the Delco's are as reliable as, say, a Sandan or some other brand.

I was also thinking of putting a filter/strainer in the suction port to protect the system in case the compressor fails somewhere down the road, as I imagine it very well could. However, I was wondering if having the filter in there could affect the cooling capacity in some way?

Finally, I was wondering if the cheap Behr receiver driers I'm seeing all over the place are any good, as I understand they're now made in China. AFAIK, Hansa is OEM, but the price is so much more than the Behr's I'm wondering if the Hansa's are worth it, considering that the drier doesn't have any moving parts.

Thanks again for the replies, and in advance for any additional info anyone can give me.

Regards,

Bill

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Bill
1981 380sl

I never had reliable a/c until I replaced every part (at the same time) and filled with nitrogen/ blah blah and finally charged with r12.

If you want your a/c to give 20 more years of reliable service, change everything all at the same time and be done with it.

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Eugene

10 E63 AMG
93 300te 4matic
07 BMW X3
14 Ford F-150 Fx2

Thanks for the quick response, which is pretty clear. But I'm just wondering why you filled the system with nitrogen, rather than freon, as I never heard of that?

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Bill
1981 380sl

You pump down first, check to see if it hold vacuum. Then charge to 200 psi of nitrogen to check for leaks. Nitrogen will absorb any moisture (humidity) in the system. Moisture+freon=acid that will eat up your seals, causing premature faiure.

Also, testing pressure with nitrogen is a helluva lot cheaper than testing with r12. You would never want to actually run the system on nitrogen.

Once you see the system will hold 200 psi of nitrogen overnight, you pump it down again, and then recharge with freon. (r12 i would hope.)

I changed my compressor 2x, reciever drier 3x, flushed 2x. Finally I changed the evap,expansion valve, o rings galore, compressor, rec/drier, condensor. It has been working flawlessly since.



It seems with these cars once you fix on part of the system, the other side will go out.

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Eugene

10 E63 AMG
93 300te 4matic
07 BMW X3
14 Ford F-150 Fx2

In my experience, assuming that it was changed to 134 due to a compressor failure is a long shot of an assumption. Over the years, people have converted to 134 at the drop of a hat.

Also, in my experience, I wouldn't do away with a York/Tecumseh compressor for ANYTHING! They are reliable and cheap. They do NOT, however, convert well. The added high side pressure from a 134 conversion is tough on them.

If the car were mine, I would simply replace the compressor if necessary, flush the system thoroughly, repair any leaks, replace the filter drier, fill the compressor with mineral oil and charge with R12, that is very inexpensive these days. It can be had for about $15 a pound, very little more than 134. This will give you a better performing, more reliable system much cheaper, simpler and less time consuming than converting to a different compressor.

I would be surprised if there's anything wrong with a Behr filter/drier. It's a quite simple component. Kind of hard to mess it up.

Hope this helps.

Woops! I meant $15 a pound for R12. Sorry 'bout that.

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2001 SLK 320 six speed manual
2014 Porsche Cayenne six speed manual

Annoy a Liberal, Read the Constitution

Larry,

Thanks very much for the informative and knowledgeable reply.

However, you raised the question I was originally grappling with when you wrote, on the one hand, "I wouldn't do away with a York/Tecumseh compressor for ANYTHING!", but, paradoxically, that you would "replace the compressor if necessary."

The reason I say this is that original question I tried to get an answer to was whether I should simply replace the chattering clutch on the York, which would be relatively easy, and risk a catastrophic failure later on. Or, should I replace the compressor, drier, TX valve and O-rings before they fail , given that the compressor could very well be 30 years old.

In the threads I've read, most people opted to replace the compressor. and one guy who said he had replaced the clutch said the next time he would replace the whole compressor, as it failed a year or two later. However, most of these threads dealt mainly with R-4's, which I don't think are as robust as A-6's?

So, is there any way to tell how long a York A6 with a chattering clutch is going to last -- given that it could already be 30 years old, and has gone more than 200K miles?

Thanks again for the reply, and in advance for any additional advice you or anyone else can give me so I can make the most well-informed decision I can.

Bill

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Bill
1981 380sl

I would like to know where $5 R12 is available. Perhaps you would be willing to sell me some?

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85 300 SD ~ 115K
82 500 SEC Euro ??K
78 450SL 164K

I think he typo'd 15. I personally have not found any really that cheap.

To the op, Ultimately, you have to do what works with your wallet. At 30 years, its really only a matter of time. Everytime the system needs service, you will lose your precious r12 unless you have recovery equipment. Although its not huge money, it work out to about $75 each time. With so many other failures you will have on a car that old, its kind of reassuring that at least you will have working a/c when it actually gets hot out.

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Eugene

10 E63 AMG
93 300te 4matic
07 BMW X3
14 Ford F-150 Fx2

Thanks for the advice. After considering all the options, I've decided to go ahead and replace the compressor, drier and expansion valve. But I still haven't decided whether to replace the hoses too. Is that something that should also be done, given that they aren't leaking?

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Bill
1981 380sl

Sorry for the delay in response.

I am assuming that you mean that you are replacing the compressor with a rebuilt Tecumseh/York.

There is no need to replace a hose unless it is leaking. That said, in the case of a refurbishment project, you can remove the hose assemblies and take them to your local hydraulic hose shop where they can do a thrifty replacement of the rubber hose.

__________________
2001 SLK 320 six speed manual
2014 Porsche Cayenne six speed manual

Annoy a Liberal, Read the Constitution

If the system is gone through, made tight and checked for leaks before charging, the chance of the need for a total recharge is not high. I would be surprised if it is a system that uses more than 3 pounds which would be about $45 worth. In today's refrigerant market, it would cost as much as $30 for an equivalent 134 recharge.

__________________
2001 SLK 320 six speed manual
2014 Porsche Cayenne six speed manual

Annoy a Liberal, Read the Constitution

Actually, the P.O. converted the system to R-134, as I mentioned in a previous post. So, even if it needs 2 lbs, which I think is its capacity, the cost of the freon isn't an issue.

But are you really saying that there will still be freon in the system even after I replace the compressor, drier, and expansion valve?

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Bill
1981 380sl