W140

[powerglide]

It's too late now that I've bought it, but does anyone know about any typical problems associated with the W140?  After just missing a nice W126, I have been completely unable to find another, so I settled for an S430 with reasonably low kms. It is second series, and so avoids the bad wiring issue, and the climate works fine.  It also has been maintained well since new, so this bodes well, and I have been advised that the '94-96 build cars avoid the known problems of the first series, and some of the growing complexity of the later build.  The sunroof appears to be the only option.  Driver's door pneumatic closer only works intermittently (I can live with that), and the climate is slow to switch the side glass from heat to cold due to sluggish vacuum (being looked at).  Everything else works fine, and it is a very impressive piece of automotive engineering, without all those embedded microchips in moderns cars that go down all the time.  Why do they do it? - build cost, I expect (like front wheel drive).

[Big_Richard]

biggest problem in my opinion with the later benz's, is that you'll basically be on your own the first time you experience troubles and be at the mercy of a mechanic or be forced to use the shotgun technique when trying to perform a repair if its not a simple problem. There isn't the same kind of simplicity or community knowledge/support available.

I'd also hardly consider a w140 to be free of  complex electronics, I think youll be quite suprised the first time you pull it apart 

[motec6.9]

Hi powerglide this should help http://ozbenz.net/viewtopic.php?f=55&t=11923 plus lots of other information on the model apparently the w140 is more complexed and costlier to maintain than the later and simpler w220 

[jbrasile]

powerglide,

140's are incredible cars and the more you drive them the less headache they give you.... they are however from an era when electronics started to completely dominate modern MB's and there are problems to watch out for:

Door vaccum pump - they never work correctly and even if you get a new one ($$$) there is no guarantee of how long it will last so you can disconnect yours or just ignore it all together

Air Mass Sensor - they do go bad from time to time causing strange running conditions

Throttle body - their wires sometimes will go bad and there is no repair, you have to replace the whole thing

A/c evaporator - pray that yours was  done already.... this is probably the single most expensive and complicated repair on a 140, or any modern car for that matter

A/c control module - 96 cars and later fare a lot better but sometimes digits will appear broken up on the display and you may also experience strange behavior, too hot, too cold, not the right air distribution etc...

Power windows may not go all the way up or down using the "one touch" function, this could be just a sensor in the window mechanism or the control module

Those are the some of the things that come to mind.

All in all 140's are the last MB's built by engineers and not accountants, they are superb highway cars and surprisingly fun to drive. I think they feel a lot lighter and smaller than they are. Drive the car as much as you can and you will see that reliability is pretty decent.

Tks,

Joe

[TJ 450]

Powerglide,

Good choice getting the later W140... now's the time to get a good one while they are still around.

However, it is a major step up in complexity from a 116.

Tim

[robertd]

Hello PowerG,

I have been driving my W140 S280 for almost 4 years now, it is a late '95 build update series but still has the more reliable 4 speed box. I have found her to be very reliable and satisfying to own.

Correction though! the W140's did not have the 430 motor, they had the 420  '4 valve' motor (M119) same designation as the 500 motor. The 430 was available in the next model S class and it had '3 valve' per cylinder.

I think you will enjoy driving the big girl around, I am continually impressed by the way they can by thrown around corners and their handling is more like a smaller sports car.

Cheers

Rob

[wbrian63]

I had a '92 300SE for several years, and have been all the way through that car from front to rear, and then some.

I somewhat disagree with JBrasile's characterization of the vaccum door closer system. The system can be "adapted" to work just fine, if you know what to do and how to do it.

The way the system works involves a timer and a pressure monitor. As you close the door, once the latch clicks to the first position (not closed, but not free to swing open), and just a bit further, a micro-switch is activated, signaling the pump to engage the mechanism that pulls the door shut.

The pump comes on, and the manifold valve opens the line to the actuator in the door that's being closed.

The mechanism in the door moves the latch to the fully closed position. When this happens, the piston bottoms out, and the pressure in that circuit builds. Once it reaches a maximum set point, the pump turns off.

The problem is that as the system ages, the pump gets less efficient, as do the actuators in the doors, and it takes longer and longer to reach the cutout pressure. As a result, the pump runs more and more and more, eventually giving up the ghost.

The system is smart enough to "off-line" any door that is taking an excessive amount of time to reach cutout pressure. The only way to get that door back online again is to power cycle the pump by pulling the fuse.

The solution to prolong the pump's life is to tinker with the pressure switch. The closer system exherts a lot more pressure than is really required to latch the doors, so reducing the cutout point to just beyond where the doors latch reliably makes a big difference in pump life.

The unit is installed in the trunk, up and to the left (passenger side in your case, if your car is RHD) at the rear. It's inboard of the trunk hinge.

It can be removed from it's perch and placed on the trunk floor, if I recall, all hoses still attached. If you open the case, you can see the pressure switch. Actuate one of the doors and see how the switch reacts. If I remember correctly, lengthening the arm on the switch (it's a threaded device) causes the pump to cut out at a lower pressure.

Just thought you might like to know.

Regards

[jbrasile]

WBrian,

I have never seen a 140 with a vacuum door assist system that works ALL the time. You replace the pump, it works for a while and then it starts to go intermittent again. Great tip about adjusting the pump's pressure switch, I will keep that  for the future! However I have seen client's cars with very low mileage and minimum use where one side works and the other doesn't, or all doors will not close, or the trunk won't close...

In my opinion the system is overkill, yes it is very "cool" to be able to just gently close the doors and have them latch themselves but they already close with such a nice "thud" by hand...

Tks,

Joe

[powerglide]

Thanks guys for that excellent info.  Yes, it's a typo - the car is an S420 W140, 1994 build, second series with the 4-speed auto trans. My mechanic said just about the same regarding the doors closer - I bought the car from another of his customers, and he knows the problem well.  He also said the car needs driving more. 

I am impressed with the way the 2-ton car handles, and with conventional sprung suspension - no self levelling system or anything.  And yes, I did take a deep breath befor forking over the $$ for it.  I really wanted a W126, but just couldn't find a good one - they're getting to old now, I guess - last one built 20 years ago now.  My next one will probably be a W220 a few years down the track.

[powerglide]

WBrian63,
Thanks for the lucid description of the door closer system - I will check that out.  It may be that the pump is now weak and the rest will fail some time soon. Thanks also for the detail on the in-door components.  I wonder if the driver door failing first is a result of its higher usage, or perhaps it is because it's farthest from the pump when the pump starts to lose its efficiency.

The system seems like an update of central locking in the W116, and I have noticed that it improved in my 350SE with car usage (up to a point).

I agree with jbrasile about the overkill: you don't find Italian cars with too much, but they break down everywhere, all the time.  Like that economy, I guess. Germans still make the best machines. And the saying goes on: French cook best (no argument - I lived there for a while), Swiss best public service, British best police (hmm, not sure about that), Italians best lovers (very doubtful).  And I CAN close the door manually, for heaven's sake!

And Rob, you are right about the ride/handling/comportment equation - if anything it reminds me a little of a 6.9 in that respect, although the W140 does weigh a lot less.  Let's just see how it works out.

Motec69 - thanks for the link to that ozbenz string - that helped a lot.  There are, as always, tradeoffs, and it sort of confirms the view that the series 1.5 (94-96) overcomes a lot of the early troubles, and stops short of escalation in electronics.

[powerglide]

Just an update for those who might consider going down this path.  The W140 is a fine car; it is more, it is really a lovely thing.  Of course it is more complicated than a W116 - it is 20 years later in technology. It is also a clear 10 years older than the microchip tangle in which the whole of humanity is embedded today.  I like the ride, the handling (amazing for a 2-ton car), the brakes, the steering - the fabulous competence of the engineering.  The smoooothness and the quietude are wonderful, and if you still own an Esky, you can stand it up in the boot (no can do in a W116 - it has to go behind a front seat). The sheer quality of every detail also amazes.  The leather, the wood, the carpets, the paint, even. You can buy one of these for $10k, and $20k will buy you the best there is to be had (they were the cost of a small house when new!).  I'm very glad I bought it, in spite of the annoying minor malfunctions that are (hopefully) getting fixed right now.  You know there are oddities: the radio antenna is embedded in the rear screen glass, but it has these two little telescopic antennae that pop up at the extremities of the rear guards when you select reverse, and they indicate the rear corners of the car. Nice for parking, but superceded by radar now, and they aren't even connected to the radio.   The radio is nice, with a Bose cassette/am/fm head unit, a Eurovox 10-CD stacker in the boot, and no less than 10 speakers in the car (mind you, I would exchange the lot for my old Pioneer head unit with a single pair of Sansui speakers - it was a lot better by an order of magnitude that anything else that I have been able to rig up in a W116).  The W140 is truly a magnificent piece of automotive engineering, and if you find a good one, they ae a freaking bargain right now.

But, dear reader, I drove my 280SE today, and I must confess to you that I actually liked driving it better.

[s class]

I used a W140 500SEL as a daily driver for 2.5 years.  Early on I got the vacuum assist sorted out by making adjustments similar to what wbrian described.  It was 100% thereafter.  It was the most awesome car I've ever driven.  But wow, what an expensive car to run and maintain.  Ultimately I gave up and drove it to a breaker's yard and handed over the keys. 

but.... I did vow that I would oneday get another one, but it must be a 600SEL, first version, black on black. 

[wbrian63]

As I noted previously, I've been down the W140 path, and while it's a great ride, it's not for the faint of heart or thin of pocketbook.

Avoid the 300SE/S320 variants. 228hp/228tq isn't enough power to move these 4,000# cars in an effective manner. The biggest problem is MB's decision to have the cars start in 2nd gear. Later models (I think) had 1st gear start. You have to push the engines hard just to keep up with around-town traffic. My average mileage was about 15 in town, and I'd struggle to get over 20 on the highway at 70-75mph. Push it harder, or load it down with passengers or a trunk full of stuff (and you can put a LOT in a W140 trunk), and mileage would drop into the high teens.

There is no other car on the road that returns the level of quiet that can be found in a W140. They are exceptional road cars, able to be driven for hours on end with little driver fatigue. I've had my car as fast as 125mph, and it felt dead-steady, ready for more speed.

I upgraded in a big way from the 300SE to a 2002 S55 AMG (W220 chassis). 360hp/391tq and I regularly see 18mpg in mixed driving and 22mph highway on long trips is easily attained. However, this car isn't nearly as quiet as the W140, nor does it have the same bank-vault solid feel.

Take a 1999 W140 S600 and compare it to a 2000 W220 S600, and I think, all things being equal, I'd probably choose the W140.

[powerglide]

S420 update: The climate control now works properly after replacing the solenoid that operates the hot air/cold air gate on the left side. Not cheap (solenoid $500 plus tax - probably $10,000 from DM Inc.), but it now works a treat. 

The auto door closer system: it works fine except for the driver's door and the boot (both will work occasionally) with the motor running.  Brian, I will follow up your suggestion as I find that I am the kind of person who is not happy unless everything works properly (obsessive/compulsive disorder, perhaps?).  Meantime I need to get the plastic plug out of the baby seat mount on the rear parcel shelf.  Someone replace the plug carelessly and crossed the thread so that the plug broke on removal, leaving part of the plug behind. Not easy, as the centre mount is pretty hard up against the rear glass. 

The leather interior is in good condition, but it would be good to know others' experience with leather cleaners and conditioners: any recommendations?  I will post this point in the interiors section as well.

Also, I note recommendations to leave the tranny in "S" mode.  Compared with my 350SE and 280SE, the S420 doesn't seem as responsive when you floor the accelerator pedal, although it will build speed, and is more responsive if a lower ratio is selected.  This is a 4 speed, so it can't be an issue of electronics.  In fact, I have a hard time detecting and difference between "S" and "E" modes.  Any suggestions?

[powerglide]

It's good when stuff works.  And the sound system is so good it would make other W116 owners weep too!  Everything is nice, but I still like a W116 and a W126 better to drive.  Something to do with the better visibility all round.  The W126 has that nice wheel, and a little smaller than the W116's.  I think that a 420SE also seems to go a little harder than the S420 - must be the 2 tons the W140 weighs.  What is it when you find yourself driving a car that is clearly superior in every way (it really is the best car I have driven, and that is quite a lot), but it's not so much fun to drive as the previous models ?