W140 Air Conditioning Issues
Thread Starter
Newbie
Joined: May 2002
Posts: 6
Likes: 1
From: Dallas, TX Burbs
1993 500 SEL
W140 Air Conditioning Issues
Let me preface my message to say, when I purchased my 1993 500 SEL on eBay 3 months ago, I bought it with every intention of selling it for a profit. Well, after putting 3000 miles on the car, I have every intention of keeping it until the wheels fall off! (Which will hopefully not be six months from now.... 
) What an incredible vehicle! I haven't even given a passing thought to my departed 1996 328i........
A question; the only issue I seem to have in a freon leak. The previous owner recharged the freon last July, and I had to do so again in early April. I live in Texas, so this is a major issue for me. Is this a sign of something familiar to you long-time W140 owners? Any and all hypothesis would be appreciated.....
Thanks!
Alex
1993 Black 500 SEL a.k.a. "The Embassy Car"
1977 Red 450 SL
) What an incredible vehicle! I haven't even given a passing thought to my departed 1996 328i........A question; the only issue I seem to have in a freon leak. The previous owner recharged the freon last July, and I had to do so again in early April. I live in Texas, so this is a major issue for me. Is this a sign of something familiar to you long-time W140 owners? Any and all hypothesis would be appreciated.....
Thanks!
Alex
1993 Black 500 SEL a.k.a. "The Embassy Car"
1977 Red 450 SL
Member
Joined: Mar 2002
Posts: 180
Likes: 1
From: Southern California
93 300E
Well, I can tell you with alacrity that the early W140's had problems with leaking evaporators.
Apparently, Mercedes never imagined these would need replacing, because they built the whole dash around it.
Everaporator replacement is a very common repair on these cars, and I've read from technicians that it is about 22 hours of shop time to replace one, and the evaporator is about $800?? Yes, that's right. I've seen pictures posted of one being removed, and the entire interior of the front of the car is removed (except the seats).
I would take the car to a Mercedes dealer or a very qualified MB independent to get this diagnosed.
I agree the W140's are probably the best S-class ever built, but they are also widely known as the most expensive to maintian, as well.
Apparently, Mercedes never imagined these would need replacing, because they built the whole dash around it.
Everaporator replacement is a very common repair on these cars, and I've read from technicians that it is about 22 hours of shop time to replace one, and the evaporator is about $800?? Yes, that's right. I've seen pictures posted of one being removed, and the entire interior of the front of the car is removed (except the seats).
I would take the car to a Mercedes dealer or a very qualified MB independent to get this diagnosed.
I agree the W140's are probably the best S-class ever built, but they are also widely known as the most expensive to maintian, as well.
Newbie
Joined: Jun 2002
Posts: 11
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From: Louisiana
86 Mercedes 300e euro
Have to correct this sorry, all 140's have evaporator problems late and old. Same goes for 124, and even the late e-320 210 chasis. I have done every model except the latest ones (havent heard of any problems except for certain s-classes ). The main evaporator problem cars of course are 140,124,129,210, and now we are seeing alot of 202 's also for evaporator problems. 140 is about 23.5 , 124 is 15.0 , 129 is 20.0 ,202 is 20, and 210 is 23.5 also. Now this is what we charge , I dont think it is the same everywhere. Those times include leaktest , teardown -reassemble , replace reciever drier and evacuate and recharge system. 
Member
Joined: Mar 2002
Posts: 180
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From: Southern California
93 300E
euro 287,
I see you've made your first post here. You really have helped a lot of people on the mercedesshop.com forum. You might recognize my name from the mercedesshop.com forum, too, as I post there almost everyday.
When you replace the evaporators, what do you replace them with?
Are they only available from the dealer, or are there aftermarket manufacturers?
Have they managed to fix the major flaw in them that causes them to leak? I mean, with parts and labor, it would easily surpass $2,000, and would be a shame for it to fail again.
I don't know why MB can't seem to make an evaporator that doesn't leak. My family has driven American cars (mainly Cadillacs), Japanese cars (mainly Toyotas), and Mercedes. I have a 93 W124, and my father owned an '81 W126 380 SEL, and the only car we've ever owned that had a leaky evaporator was the Mercedes, and all of our cars we've kept past 200,000 miles. My a/c in the 93 300E (3.2) is still original, so I'm keeping my fingers crossed.
I see you've made your first post here. You really have helped a lot of people on the mercedesshop.com forum. You might recognize my name from the mercedesshop.com forum, too, as I post there almost everyday.
When you replace the evaporators, what do you replace them with?
Are they only available from the dealer, or are there aftermarket manufacturers?
Have they managed to fix the major flaw in them that causes them to leak? I mean, with parts and labor, it would easily surpass $2,000, and would be a shame for it to fail again.
I don't know why MB can't seem to make an evaporator that doesn't leak. My family has driven American cars (mainly Cadillacs), Japanese cars (mainly Toyotas), and Mercedes. I have a 93 W124, and my father owned an '81 W126 380 SEL, and the only car we've ever owned that had a leaky evaporator was the Mercedes, and all of our cars we've kept past 200,000 miles. My a/c in the 93 300E (3.2) is still original, so I'm keeping my fingers crossed.
Newbie
Joined: Jun 2002
Posts: 11
Likes: 1
From: Louisiana
86 Mercedes 300e euro
We replace them with an ACM evaporator. They dont leak like the factory ones. Now on the 210 chassis you cant replace them with an ACM cause they didnt make the design correctly, so you have to go with factory. This is an ongoing problem with Mercedes that I dont understand but maybe they will learn since they have had this problem for the past 15 years or so. If you would like to own a 140 and have it serviced properly plan on spending 1-2k on repairs per year . I know that seems like alot but if only you knew the problems they have and how expensive it is to repair these problems. I guess the first couple years hurt the most after you but a used one.
Member
Joined: Mar 2002
Posts: 180
Likes: 1
From: Southern California
93 300E
Do you think most Mercedes Independents know about this brand? Is ATE a widely known brand?
It's good that they don't leak, but do you know what it is about the evaporators that they fixed?
For example, are they using a different metal?
Thanks.
It's good that they don't leak, but do you know what it is about the evaporators that they fixed?
For example, are they using a different metal?
Thanks.
Newbie
Joined: Jun 2002
Posts: 11
Likes: 1
From: Louisiana
86 Mercedes 300e euro
Yes most shops know about ACM evaporators. They changed from alluminum/copper to straight alluminum. Now on the 210 chassis they are from factory straight alluminum but they eat away from the inside out due to moisture or air in the system. This is our theory , Mercedes will never admit any problems concerning evaporators, or even their wiring harness' for that matter. Dont expect Mercedes to say they screwed up cause it will never happen.
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MBWorld Fanatic!
Joined: Nov 2001
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From: Bloomington, IN
1997 Toyota Tacoma 4x4
Evaporator failures don't seem to be as common in the later models. Granted, I've only been working on MB for just under 2 years, but the only evaporators I've seen fail on a regular basis have been 202's, 124's, 140's, and early 220's.
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MBWorld Fanatic!
Joined: Nov 2001
Posts: 2,332
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From: Bloomington, IN
1997 Toyota Tacoma 4x4
This is a picture of a '97 S420 about halfway through an evaporator replacement. This is just the dash and carpeting removed, the whole heater case still has to be removed.
Thread Starter
Newbie
Joined: May 2002
Posts: 6
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From: Dallas, TX Burbs
1993 500 SEL
Well, what a can of worms I've opened here......worms with teeth, from my perspective as a 140 owner!! As a person capable of very minor mechanical work, and approaching this from a purely practical angle; if the AC needs recharging 2-3 times a year due to this problem, wouldn't that option make better sense rather than making a $2000 repair? Incidentally, what does this nasty, expensive little bugger called an evaporator do??
Newbie
Joined: Jun 2002
Posts: 11
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From: Louisiana
86 Mercedes 300e euro
Didnt mean to put a bad taste in your mouth , its just another repair that has to be done. Yea you can charge your air 2-3 times a year, lets see your looking at 1.4 hours to evacuate and recharge ( by book) and another 30. bucks in freon , then you loose all of the oil from the system out the a/c drains and pay another grand for a compressor that will lock up. It affects the whole system. I have 2 124 evaporators that I am doing today and one 140 scheduled for tomorrow and a late model e320 for thursday. Its a common problem down here, sure it is everywhere. @ grand is the normal for this 140 , I wouldnt ever tell a DIYer to try to tackle it themselves. I have got these cars towed in from other shops that got lost halfway into the job , its not a pretty site.
Member
Joined: Mar 2002
Posts: 180
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From: Southern California
93 300E
I wonder if the evaporators fail down there so much because of the humidity.
I'm in Southern California, and I've been to a get together with the members of the mercedesshop.com forum, and there was a W140, a W108, a W116, and about a dozen W124's, including a 500E, and not one of us has replaced our evaporators.
You know how everyone talks about the great climate in So. Cal, what with the dry heat and all... :p 
I'm in Southern California, and I've been to a get together with the members of the mercedesshop.com forum, and there was a W140, a W108, a W116, and about a dozen W124's, including a 500E, and not one of us has replaced our evaporators.
You know how everyone talks about the great climate in So. Cal, what with the dry heat and all...
:p
ac, air, airconditioning, car, condition, conditioner, conditioning, drier, embassy, evaporator, mercedes, steering, w140, wheel, zebrano
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