You might be a bit surprised to see another Mercedes on this list. The S-class is Mercedes’ top of the line car. The S-class is the vehicle of choice for heads of state, captains of industry, and Hollywood stars. Princess Diana’s fatal car crash was in an S-class. (Her driver, who wore his seatbelt, survived the 100+ MPH crash.) Without a doubt, the S-class is a more luxurious and comfortable car than the E-class, albeit less nimble.
The W140 S-class was sold from 1992 to 1999. It is perhaps the most over-engineered Mercedes-Benz of all time. For example, the W140 has dual-paned windows that insulate the cabin from noise and heat. When Mercedes built the W210 E-class, they picked a target price and built the best car they could for that price. By contrast, the W140 was built with no price target. Whatever the car cost to build, that’s what they charged plus a little profit. Consequently, the price of many S-class models brand new was north of $100,000.
Good news for the used car buyer! In our modern society, new luxury cars are the greatest transfer of wealth from the rich to the not-so-rich. These $100,000 S-class can be scooped up left and right in the pre-owned car market for between $10,000 and $20,000. In many cases, S-classes are less expensive than E-classes of the same age and mileage.
Why on earth would the S-class cost the same or less than the E-class if it’s a better car and cost so much more brand new? Two reasons, I think. First, the E-class looks like a newer car, because, well, it is a newer car. The S-class styling is about half a generation behind the E-class. Secondly, the S-class has so many gizmos and is so overengineered that when something does break, it’s more expensive to fix. For example, the automatic door (x4) and trunk closing mechanisms tend to be troublesome, and they cost $600 each to replace. The A/C evaporator core on the W140, particuarly the 1992 to 1995 ones, often develop leaks. This would not be a problem for most cars. However, Mercedes, in their infinitie wisdom, decided to build the entire car around the evaporator. The ~$3,000 repair requires tearing the entire dash apart.
The W140 was sold in the U.S. with one piece-of-junk engine and four excellent engines:
S350 Turbodiesel (OM603) — As nice as diesels are, avoid this car. Mercedes took one of their best diesel motors and bored it out for more power. Unfortunately, they bored it out too much, leaving insufficient material for cooling the number one cylinder. As a result of this faulty design, the engine fails prematurely under normal operation.
S320 (M104 Inline-6) — This is a wonderful motor: perfectly balanced, double-overhead cam, 228 HP. This same engine powers the 1996 and 1997 E320. Although not as powerful as the V8s, it can motivate the W140 far beyond any sane speed; it just takes a little longer to reach terminal velocity. Expect the low-speed acceleration to be placid. Once you overcome inertia, watch out — this car can move! Be warned, the M104 has trouble with a leaking head gasket every 75,000 to 100,000 miles (~$1100 repair). Despite weighing about 4500 pounds, the S320 returns about 22 MPG.
S420 (M119 V8) — This too is a wonderful motor. At 275 HP, it’s stronger than the S320, but doesn’t drink as much gas as the S500.
S500 (M119 V8) — Excellent engine. 300-322 HP, depending on year. Nearly the performance of the S600 without the maintenance tab.
S600 (M120 V12) — Excessive. 389 HP, 420 ft-lbs. There’s really no point to owning this car unless you want to tell your grandkids that you owned a V12.
If you buy an S-class, stick to the 1996 to 1999 models. The earlier models had the aforementioned A/C evaporator issues, suspension wear problems, and a short-lived and very expensive biodegradable engine wiring harness.
- Helpful Links
- MBWorld W140 Forum
- BenzWorld W140 Forum
Vehicle info and problem particulars:
2000 E430 Sport. Driver's side air blows whatever is outside (i.e., warm/hot). Passenger's side is getting cool, but not as cold as it once did. Slight hissing noise at times behind the vents (i.e., emanating from the engine compartment).
Sensor values:
1 – 92
2 – 102
3 – 92
4 – 86
5 – 92
6 – 198
7 – 16
8 – 141
Error codes:
b1227
b1234
anybody getting any responses ?
I'm in the middle of moving cross-country and will begin addressing
questions once I'm settled back in!
My boyfriend figured out what was wrong with our air conditioner, but I was going to post about our troubles here. I just wanted to say, I think it’s really great what you’re doing. It’s so cool that so many people have responded. You’re very nice!
David- Please help with my 98' E300!? I drive this thing everywhere and I have went 3 weeks without air. Here are the codes:
VALUES
1-32
2-35
3-72
4-71
5-34
6-83
7-24
8-65
CODES
E61 R227
E61 231
E61 232
E61 234
E61 235
E FF
Any help would be greatly appreciated!! I will help you move if you can crack this one. I am driving this thing 1000 miles a week and I am riding in a hot car with hot beer, where would you like me to send it
2001 e320
Sensors
1 – 82
2 – 76
3 – 112
4 – 114
5 – 143
6 – 188
7 – 03
8 – 103
Codes
E61 234
E61 416
E FF
Thank you so much for your help! Help me out and I'll donate to the cause! =)
I released the pressure of my system then recharged with R-134a to about 40psi. The initial read was about 65psi. Can't get anything cold out of my car.
I sure hope you're able to find this post! I'm not sure why it isn't posted on the top/bottom.. It's just floating out here in the middle.. =(
Hi,
Your main problem is a faulty evaporator temperature sensor. It's reporting an implausibly high temperature (#5=143 degrees) which is causing the A/C system to shut down to protect the evaporator core from freezing. The computer does this when it determines that the evap temp sensor is unreliable.
Your refrigerant pressure (#7) looks low. It's hard to say whether your system is adequately charged or not based on pressure alone. Once the compressor is running after replacing that evap temp sensor, you'll have a better idea. Note that you need the compressor engaged in order to charge the system since the (relative) suction from the compressor on the low-side line is needed to draw the refrigerant out of the can.
Blake
thank you so much for your help! i think it's absolutely awesome that you're willing to help out those of us in need! you can expect a few beers from me!!
Hey Blake first, thanks for being such a great resource and money saver, here are my codes:
1-87
2–87
3-85
4-87
5-84
6-136
7-00
8-85
EB1234
EB1241
EFF
Thanks for your help!
Ray,
Looks like your system is empty and needs to be recharged. The
refrigerant pressure sensor is reporting zero pressure. Sometimes this
is caused by a defective sensor, but that happens rarely. Look
through my previous responses for instructions on how to bypass the
pressure sensor and how to reset the codes if you want to give that a
try before recharging.
If your system is empty, the most common source of leak is the receiver-dryer.
Blake
I sent in a question 2 months ago, if you have time could you please check it out and give me some advice. Thanks for any help.
Hey Blake, I have a 1998 E300 TD.
Symptoms are: A tiny bit cold for the first 3-4 minutes, then blows whatever air temp seems to be outside.
First about the faults. I had a bunch of faults that I was able to clear out to a E-FF status with zero showing. A Winter ago I had Firestone replace the Serpentine belt which is where I think the problem might have started. Also checked using my CodeKey ODB reader and no codes thrown.
Here are my error codes, 1st reading is after 3 minutes, 2nd reading after 20 minutes driving to work. These are in Celsius on the left, Fahrenheit on the right in parens:
sensor 1- 37, 36 (98.6, 96.8)
sensor 2- 32, 30 (89.6, 86)
sensor 3- 40, 37 (104, 98.6)
sensor 4- 40, 37 (104, 98.6)
sensor 5- 77, 77 (170.6,170,6)
sensor 6- 37, 95 (98.6, 203)
sensor 7- 08, 08 (bar)
sensor 8- 33, 42 (91.4, 107)
Since sensor 7 reads only 8 bar, so I'm thinking that with no fault codes I might just need a recharge and the problem could be a leak somewhere. A confirmation would help.
Does anyone have a link to the 210 parts numbers for all the sensors?
Thanks in advance,
Jesse
Fairfield, County, Connecticut
Jesse,
In short, your problem is the evaporator temperature sensor (#5). Replace that and you'll be back in business.
Look through my other replies if you are interested in a more comprehensive explanation of why this sensor causes this problem.
Blake
Thanks Blake, I came to the same conclusion last night after adding a can of 134a only to have the compressor blow much colder air for approximately the same short time span of a minute or two,
thanks for your help, donation to the Blake Cameron Wildlife Preservation Fund to follow. :>)
Jesse
Hi Blake,
The E55 has been sitting relatively idle. I have replaced the sensors and had the unit charged. EC light is not on. Air temp sensor in front, even after replacing shows error, though I can read outside temp on instrument cluster.
What's the next step – vacuum leak, head unit, ?
Thanks
John F. Burr, Ph.D.
Continuous Term Lecturer
Krannert School of Management
Purdue University
615 Carrolton Blvd
W. Lafayette, IN 47906
765.404.4114
Mike,
Thanks once again for the beer money. I have good news for you. It looks like all you need is a recharge. None of your error codes are significant. The only one that might make a difference to you is B1231, the engine coolant temperature sensor. That sensor informs the climate control unit when it's appropriate to start blowing (hopefully warm) air after staring the car in the winter.
As for the air conditioner, your refrigerant pressures look good. The vent air is warmer than it should be (40s), but still cool enough (60s) to tell that the A/C is working. Often when the refrigerant is low, you'll hear a hissing noise emanating from behind the center vents and notice a temperature difference between the left and right center vents. A simple recharge should put you back in business. In the interim, you can try using the recirculate button to reduce the temperature of the air being drawn through the AC (assuming the interior is cooler than the outside).
Blake
I have '98 E-320 which gave a problem with the high speed fan motor not comiing on. The blower motor was changed by the dealer a couple of years ago for a hefty sum of $1200. Starting late last year the AC would just not cool. All I am getting is the hot air. I am hesitant to take it to the dealer because the price will vary from $297 (recharge) to may be $4500 (coils replacement). I read your artical and decided to take down the readings and see if could recharge 134a myself. Here are the readings:
#1 30,#2 29, #3 31, #4 31, #5 49, #6 65, #7 01, #8 28.
The error codes are: E61 227, E61 231, E61 233, E61 234, E61 459, E FF, E.
The EC light can be turned off. If you feel that the rfrigerant needs to be recharged, would you let me know the approximate location of the low pressure valve? I have opened the hood andcan see a chrome pipe going from the compressor to the body below the brake fluid cup. This pipe has a valve with a plastic thread cover.
Thanks in anticipation.
SK
I have a '98 E320. Two years ago the high speed blower was replaced by the dealer for a hefty $1200. Late last year, before the Fall, the AC stopped working blowing only hot air. The EC light can be turned off. I was told by the dealer that the recharge will cost me nearly 297 and the worst case scenario is $4500 for changing the coil. I was encouraged to read your article and decided to take down the sensor readiings and the error coses to see if it is indeed just the recharge that is needed. I think I can recharge it myself if I can confirm the location of the low pressure valve. I had looked under the hood and found that the chrome pipe going from the compressor to the dash just below the brake reservoir has a valve with plastic screwed cover.
I have collected the sensor information and the errorcodes per your guidelines. Here they are:
#1 30, #2 29, #3 31, #4 31, #5 49, #6 65, #7 01, #8 28.
The error codes are:
E61 227, E61 231, E61 233, E61 234, E61 459, E FF, E
I will appreciate it if you can put me inthe right directions. Thanks in anticipation.
SK