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  #1  
Old 06-18-2003, 02:40 PM
Lockman's Avatar
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Unhappy S Class A/C system

I have a 1995 S420, 130,000 mis. Owned for past 6mos. A/C was not working, took it to a reputable A/C service center (not Mercedes) They found it low on #134 Freon, filled it up and checked for leaks. It worked fine for about 7-10 days, then quit again. Took it back, said it was low again (very little) and again could find no leaks. They said it could be the evaporator and that could only be done at the dealer as they had to remove windsheild, etc. to get at it? Anyone ave any input as to what it most likely could be? If I take it to the dealer (local Mercedes) how much money do I take out of the bank to find/fix the problem?

Thanks in advance!
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  #2  
Old 06-18-2003, 03:12 PM
LarryBible
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To test the evaporator for leaks, put in UV dye with the recharge, then examine the condensation water with a black light, preferably in the dark. If there is UV dye in the drain water, then you can start thinking about a withdrawal at the bank. I fully expect that this withdrawal is a 4 figure amount.

Good luck,
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  #3  
Old 06-18-2003, 03:39 PM
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You may mean banks-- [ plural].

You can also check a suspect evap with a freon snifer/detector up the a/c drain hose .. Best to shut car down overnight [windows closed helps] and test next day before starting.
The freon is heavier than air and settles at the bottom of evap enclosure and a decent leak can sometimes be picked up here....
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  #4  
Old 06-18-2003, 05:34 PM
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I seem to recall a figure of 21 hrs. shop time for this job in the 126 S class cars. 21 x hourly rate + evap unit + additional this and additional that and you are well into LBs 4 digit estimate. At $75 and hr. you could be looking a close to 2 grand for just the labor - everything included.

I realize yours is not a 126, but I suspect the setup is very similar.

Last edited by 1991300SEL; 06-18-2003 at 05:44 PM.
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  #5  
Old 06-18-2003, 05:52 PM
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140 AC

All 140s up to the late/mid nineties seem to have evaporator issues. If the factory steps up and helps it can be somewhere near 2,000. If they dont figure twice that, it depends on your relationship with your dealer. The wind shield stays in place, the whole dash comes out, along with some other stuff. There are probably good AC shops, but I would warn you experience helps, and this seems to be a common problem. While they are in there they should replace the charcoal filter, on my car they replaced hoses, evaporator, and the dryer.
I had such a bad 99ML every time it was in they were doing a 140 AC for someone, and I happend to see the process in different stages. There is a lot of room for error, and having the parts available is a help.. now go and negotiate.
PS.
I took the car in and they scaned the codes, and they never bothered to charge it (I tried and it only lasted a few days) Did not tell them!
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  #6  
Old 06-18-2003, 06:52 PM
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I am feeling a little faint after reading the replys! Peter, you mention the factory getting involved? I can't believe they would do anything about an 8 year old car, let alone admit they had a serious problem with the 140's in this area (A/C). I am supposedly the second owner, the dealer I bought it from sold it new and it is the only car I bought from them. I did buy a new 99 C280 from the other dealer in town. I have owned a 86 300E, 81 380SL, 99 C280 and this 95 S420. There is no comparison to the "S" class as it is the ultimate driving machine to me. I bought it right, so I may just dive in and invest the $$ to get it fixed.

Any suggestions on how to go about contacting the Mercedes people? I guess it wouldn't hurt to try.

Thanks to all!
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  #7  
Old 06-18-2003, 11:19 PM
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Common problem on that car. The above info is right, in that you're going to be at least $2K light if MB chips in, probably $3.5K or better if you're on your own.

They started with the AC evaporator on a CAD drawing, and then designed the remainder of the car around it. It's a hulluva tough job and requires removing most of the front interior of the car.
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  #8  
Old 06-19-2003, 08:40 AM
LarryBible
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I want to make sure you don't do something drastic before proper diagnosis.

Yes the evaporator is a common problem, but that does NOT mean that your evaporator is the problem for sure. Before you get involved in this massive job, MAKE SURE THAT THE EVAPORATOR IS LEAKING. Use UV dye or a leak detector to absolutely CONFIRM that this is your leak. There are lots of other places that can leak.

I just want to make sure you don't get carried away since the thread went off in the direction of the dreaded evaporator problem.

My 124 car also has one of the problem evaporators, but it has been in there fifteen years now and still does not leak. It is very easy to fall into the trap of replacing a part because it has a bad reputation and is a known problem. It's one thing if it is $2.00 part that you can change in fifteen minutes. It's quite another if it is $300 part that takes over two days shop time to replace.

Look before you leap.

Good luck,
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  #9  
Old 06-19-2003, 10:31 AM
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EPILOG-

Talked to the Mercedes dealer, confirmed what has been said about defective evaporators in this model. Quoted $4,000.00
for the job. Said Mercedes would not be of any help, car is too old.
Larry, thanks for the words of caution about jumping to conclusions, however, even on the remote chance it is NOT the evaporator, what ever is leaking is not accessible under the hood or the A/C shop would find it, wouldn't they? Mercedes will charge me a bundle just to check it out.

I am going on vacation for two weeks and will think it over. My inclination is to trade it in to another dealer. It will stay charged for about 10 days or so, so it will work when they try it. I wouldn't feel a bit guilty about it as I am sure they knew of the problem when the sold it to me. I would never sell it to private party and not divulge the problem. I wish now that I had never stepped up to the S class as it spoiled me for any of the others!

What specific years to avoid this problem again? Also, is the S600 V12 97-99 a car to stay away from due to maintenace issues?

Thanks!
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  #10  
Old 06-19-2003, 10:55 AM
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<>

Not that easy..
If they put dye in it when it was recharged , they would have a better chance of finding a leak, but you do not mention this..
What Larry is saying , and I agree... Put the dye in and then look for leaks .. an under hood leak w/light will now be more evident and easier to find..the dye is not just to test evap.
It will test the whole system...
I have seen many under hood connection leaks that showed after dye testing that did not show with a snifer or observation.
Many times , the recharger just visually looks for signs of oil at connections and calls that a leak test..
I would try the dye..and give it a couple of weeks to show..
A high side leak will show up more when a/c is on [ more pressure in that part of system] and a low side [evap] , tends to leak more when a/c is off..[ more pressure in evap when a/c is off]
[The reason for my other post of snifer after leaving car overnight for testing evap]
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  #11  
Old 06-19-2003, 11:22 AM
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I brought my '93 300 SD back to Mercedes Benz Manhattan, the place I bought it from in '95. The AC evaporator had a sudden massive failure. I added the Tracer dye and it was coming out of the drain. The car would not hold a charge overnight. Had it been a slower leaak I might have tried a Cryoseal treatment ($400). I brought it back To Mercedes Manhattan hopeing they would help me out with this known problem. They had the car for 24 hours. I spoke to the salesman I bought the car from, two service managers, a write-up guy and the customer rep in NJ. NO ONE will admit to a known evaporator problem. The car had 57,000 miles on it at the time (July '02). Sure, the car had been 9 years old at the time and was long out of warranty. Since I do all my own work on the car I had no rapport with them. They wanted $3200.00 to fix the car. I bought a new evaporator and will do the job myself. It seems that Mercedes won't go out of the way to instill good will.

Lockman: I have a '99 S600 with 102,000 miles on it. I bought it on e-Bay in May, '02 with 97,000 mi. for $34,900. It has been virtually troublefree. I just replaced the rear accumulators which I understand last about 100,000 miles. I think that Mercedes worked out all or most of the bugs of the earlier '90's 140 chassis. This is an awesome car, but so is the '93 300 SD!

Last edited by mr. Goodwrench; 06-19-2003 at 11:29 AM.
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  #12  
Old 06-19-2003, 12:18 PM
LarryBible
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I mostly agree with Lebenz. Although they won't warrant a problem with a 8 year old 100,000 mile car, they still do a good job in the good will department WHEN COMPARED TO most of their competitors.

Case in point, the Trap Oxidizer problem of the '86 and '87 diesel cars. As late as about two years ago, MB would replace the ENTIRE EXHAUST SYSTEM when one of these cars came into the shop. This was sometimes done without the customer even asking for it.

Case in point, the wiring harness problem of the M104 engined cars was taken care of long past the warranty limit.

They might not be taking care of the evaporator problem on this long out of warranty car, but their track record is better than their competitors as far as taking care of admitted engineering blunders.

I know it is a bitter pill to swallow regarding the evaporator, but how many new MB car payments can you make for $3,000? Not many. If the rest of the car is in good shape, you would be well served to replace this evaporator with an improved version, swallow hard and enjoy the car.

Best of luck,
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  #13  
Old 06-19-2003, 01:06 PM
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Another 0.02 cents. . . .

Lockman, there are some variations on these alternatives:

1) if you really want to sell the car, then charge the system, don't add uv dye, and sell/trade it in. Buy a newer S class car, not necessarily the S600 series. A later 500 would be ok.

2) if you want to keep it, then try a leak sealer such as described in my web page (click 'www' icon below) under Menu #16. If it's a small leak, then it will stop it and may work for many years. If it doesn't, you've lost nothing since the system needs rebuilding anyway, so this is precisely why leak sealers were invented.

Of course, there's some pros/cons of using this but in your and my situations, it was right for its use.
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  #14  
Old 06-19-2003, 02:17 PM
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There is much dismay to Mercedes' not covering the cost of repairing the evaporator problem in W140 (and other) chassis.

But, I'm amazed they covered ANY of them while the cars were beyond warranty. The same holds true for the 3.5L 6-pot diesel engines. Even with quality makes like Honda and Toyota, you'll be very lucky to have any out-or-warranty-period repair covered.

Now, you can make some argumene that these are "Mercedes-Benz" automobiles, and they should hold the bar higher. I think in many cases they do. Try any of the "Big Three" (from pre-merger days). Think you'd get any sympathy? Ha!

Think about the fact that even the problematic evaporators last years, sometimes a decade. How long do we expect MB to cover the car once the warranty runs out?

In my own experience, part of the problem comes in relatively low (compared to new) resale prices for S-Class cars. I know more than a few folks that stretched to buy a used W140, and then couldn't afford the repair bills. These were NEVER designed to be economical to operate. They are overly complex, leaden down with one feature after another, and often contain technology that has not been mass produced or debugged yet. That's why I own a simple C-Class. I don't want the headaches that come along with owning a flagship car. I owned a 911 Turbo, so I've my fair share of wallet-busting days.

The other problem I hear is low mileage vs. time. The other day I was at the dealer and there was a fellow with 1991 W126 560SEL hoping to have some repair covered. He was crying the blues because the car only had some 50,000 kilometers on it. "Why would it break already" he kept whining. Already? The car is nearly 13 years old! It's my experience that time wears just as bad if not worse than mileage.

Now that I've ranted, good luck on the evaporator repair if it required.
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  #15  
Old 06-19-2003, 02:25 PM
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Lebenz: I'm not sure, but I don't think I stated that I expected anything from Mercedes Benz, on the contrary, I would not expect any mfg. to warrant an 8 yr. old car. I didn't even call the Rep.

You make some good points, especially the about the false economy of trading it in. At the time I bought it, it was priced $5/6K under market at $19,000.00 The car is pristine in every way. The only issues with it are that both headlight assys. are cracked, but function properly and the auto-close feature on the driver's door only does not function. It is Moonstone Gray which I don't see too many of. I have talked to two other A/C shops, and the both say they will not do the UV dye test as it contaminates their equipment? I am taking it in Monday 6/23 for another test done electronically the call a "sniffer". Let's see what they find.

My heartfelt thanks for all your input, you are a great and knowledgeable bunch. I have got enough advice to keep me busy for a while!

Will keep you posted.
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