Hello All:
Long time DIY'er & dealer tech! New to this forum & looking for input for Pre-Purchase-Inspection of 97 - 99 S320 / S420.

Familiar with the W126 series but not W140 as far as fail-points!

Any advise greatly appreciated.............

TBJCC001

I just bought '97 S320 with 109K dealer serviced and I have all records
Here are a few based on this car and forum based knowledge.

1) Headgasket - Has it been replaced already. If not it probably eventually will fail.

2) Wiring Harness should not be a problem

3) Blower Motor Regulator - common failure, replaced on mine

4) MAS Air Meter - Replaced on my car at 70K

5) Rear Window regulators failed multiple times

6) Outside mirrors - both had been replaced

7) You would want to know whether the Evaporator had ever been replaced.

8) Check to verify that proper MB coolant has been used, not the green stuff.

9) Lower control arm bushings - Mine were shot and had them replaced.

10) My car has several repair tickets for issues with trunk latch. The vacuum assist door closing system has never failed, but they replaced the latch and adjusted the trunk several times.

11) I would also want to know whether the transmission fluid had ever been changed.

Other than that, I would say that it would be a normal Pre-Purchase Inspection.

Steve
'97S320
'92 300E Sportline

Thanks a bunch! That falls right in line with the reported conditions I've been finding online.....

Do you have the LWB or SWB? And how do you like it?

Long Wheelbase. Have driven 300E's for 75K on '90 and 140K on '92 Sportline.

Most of my travel is business and involves long interstate driving. I have loved the 300E's, but for road trips the S class is the real deal. Comfortable, much more quiet, about the same fuel economy, and much more room. Furthermore, it's modern with electronic climate controls and a wonderful Bose sound system. Mine has Radio, Cassette, and Trunk CD changer.

The biggest difference is in steering and handling. They are just vastly different. The 300E has , to me, the perfect amount of boost. The 140 has variable boost. Around town you can drive it with one finger, on the highway the boost decreases, but it is still lighter than a 300E. You get used to it. There is more brake pedal travel on the 140 before you actually engage brakes. 300E is immediate. So it's simply sort of a limo, calm, smooth approach versus 300E sports sedan approach. The 140's suspension feels soft in the curves, but after you master it, the car can be driven very fast in corners.

On the 140 you have two wipers, but driver's side does telescope. I don't miss the single wiper. 140 projection headlights are good, not Euros, but good enough. Paint quality is really good.

I drove my '92 yesterday. It felt positively archaic compared to the 140.

Steve

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I would suggest a 99 only. Recently my 722.6 transmission gave some issues and I had to replace the Valve body. I saved about $700 having a car with all the latest rev firmware on the computers as the computers did not have to be replaced as well.

I would avoid any of the v8 powered cars as the M104 has plenty of power and is MUCH cheaper to maintain 230hp vs 275 for the entry V8. Avoid the hydropneumatic suspension like the plague and avoid cars with rear A/C as there are pressurized lines that run under the car that can rust that will take down your whole A/C system if they fail.

My car is the short body. While not as roomy in the back as the LWB models its easier to park and has better handling.

Overall I have been VERY happy with my 140. One first step when buying one of these cars is to locate a mechanic that you trust. Many of the high end indy shops look at 140's as the gravy train as they do require expensive service and repair. Find yourself an honest smaller shop and you will be much happier in the long run and won't hear "140's are expensive cars" every time you come in for something simple.

While you can try to buy a car that has has service done to it I would not worry with that. Buy a well maintained car with a decent service history (does not have to be perfect) and you will be fine. 140's are nice cars and your just going to have to be prepared to spend money. I personally don't mind spending money on upkeep for a nice car as I keep my cars for a very long time. Also keep in mind just because a previous owner paid to have something repaired does not mean it was done right. I would rather have the chance to oversee major repairs rather than accept the shortcuts and cheap parts that a previous owner's budget demanded.

Watch your years on this one - the early V8s missed several of the problems of the early 3.2s. In that era I think it goes the other way - V8s have been cheaper to maintain than the sixes. The 3.2s were pretty much sorted out by 96 or so.

I tend to keep my cars for a while and plan ahead for a top end overhaul. V8's have two heads doubling the cost of head gaskets and top end engine work. So I guess it really depends on your point of view and how long you plan on keeping your car around. For me a scant 45 horsepower and the bragging rights of a a V8 engine don't justify the costs over the lifetime of the car. Regardless of the year and regardless of the engine the top end gets overhauled eventually.

119 top ends are not being overhauled in any significant numbers and it's unlikely they ever will be - 1) they're not failing, even with many in the 200k to 300k range, and 2) it's too expensive, 32 of everything, etc. Fortunately or unfortunately they've become throw away motors. If you blow one you replace it with a used motor, which are quite plentiful. Pretty much the same thing can be said about the 104 - very stout top ends. The days of MB engines overhauls are on the decline, in part because the market value of the cars is not there.

Maybee. With the 104 at least the top end overhaul is possible. The V8's don't provide enough of a power difference to make them worthwhile to me.

My indy , who tells me he has done many headgaskets on M104's, says he has never had to do a valve job on them. Something to do with the valve train design.

Steve

M119s (V8s) are a thousand times MORE reliable to M104s (L6). I can personally testify on this comparing my S with my E 320 T.

Having a good friend with a SWB S 320 to compare at (same year as my S 500 L), I can also assure you that the LWB has considerably a much better ride. On highway trips, the V-8 matches or even betters the L-6 fuel consumption. On town driving is another story...

But, generally, a well maintained W140 should be as reliable or even more reliable than any other M.B., including the W126 and W124.

__________________
A. Rosich
CL 500, 1998
S 500 L, 1998
E 320 T, 1995 [Sadly sold ]

I'd like to thank everyone for their responses to my initial inquiry! And appreciate amy further comments.

I'll do MOST of my own repairs! My only concerns would (naturally) be the BIG TICKET (trans & engine) design failures!
I've done several Head Gaskets, but NOT on this model! Will study in depth the Svc/Gde & Forum(s) for tips...........

Have any of you W140 guys crossed over from the W126 & how would you compare for endurance & reliability?