1991 W126 advice needed - PeachParts Mercedes-Benz Forum

dan hirsh · #1 04-18-2007, 12:34 AM

Hello Folks:

In the almost 2 years that I have owned my 1994 E420, it has been a thrill to drive it. Yeah, it's expensive to maintain but par for the course.

Before I discovered the W124 line, I always knew about the W126 cars especially the 1991 560 SEL, SEC and the rare 300SE. The SL's are not of interest.

I am ready to sell my E420 and try something else and would appreciate any words of wisdom or caution about getting into the W126 series. Some questions:

How does the handling and cornering at high speeds of the W126 series compare to my E420?

Gas mileage?

Outstanding issues worth it? (wiring harness, evaporator system, air suspension reliability)

How does the 420 compare to the 560?

It's boiling down to either a W126 or the ever elusive E500 or 500E (if I can find one at a sane price).

As always, thanks for reading.

D.H.

Hit Man X · #2 04-18-2007, 03:41 AM

Dan -

You need to narrow down really what you'd like and if the extra bits on the 560 you actually need/use (i.e. SLS, heated seats, etc) as they do cost a bit more to maintain even for the DIY. Some of the options on the 560s you can and do find on 420s if you shop around. Heck, my SDL has power recline and heated seats and my 420 has power recline too.

Performance between the M103 and even the M116 is going to be pretty different also. Loads more low speed torque and will pull very strong to the shift too... the M117 has more torque and horsepower than the M116. The 420 is probably the best between the three for power, economy, features, etc. Just a fine machine for the money.

Economy is going to be pretty similar between the three freeway. The M103 will do a bit better as the motor is smaller, but it will tach up pretty high due to the short gearing out back (mine is going to receive the 2.88:1 to drop it down to a more refined level). Figure 20-23 for the M103, 18-22 for the M116, 16-21 for the M117. OF COURSE this will depend on your right foot for passing, cruising, geographics, use of A/C, etc, etc, etc. City driving is always lower, I usually figure 3-6mpg difference from highway cruise.

I have not driven a 4.2L M119 W124, just ridden. Seemed very stable at all speeds and ran like a bat out of hell, I have driven an M103 powered one and it rides a bit better than the W126, as it should... the suspension system is newer. Handling is also slightly better as it's more of a four door sports car where the W126s are large cruisers. I've had no issues tossing the 126s around into corners, they do handle rather well...

No wiring harness issues I've come into contact with. I own a VERY early production W126 (number 7200) and a very late 1990 model... no problems on that aspect. HVAC is somewhat tricky on them (usually the head unit), but it's very easy to service. Vac pods go bad, they're easy to rebuild. You do not want R134A. Evap cores do go bad on occasion, my '90 has a bad one. It's a good weekend project, not an issue to me. SLS issues typically arise from infrequent or nonexistant SLS fluid changes or bad accumulators. Accumulators are not too expensive. The height valve does go bad at times, but again... this is rare.

My best advice - drive all three of what you are comparing to make YOUR decision. You'll know what best suits you after driving all. I'd hang onto the E420 as it's just a fantastic, all-around vehicle then pick up a LWB 560. The SLS is a VERY welcome feature for me and I don't mind the economy loss for extra power.

The 300SEL isn't too swift around town, but what do you expect with a small motor? It's a good freeway car for the cash. 560 does it all, but lacks in fuel economy somewhat. 420 is NEARLY as quick as the 560. You can also bolt on Euro dual manifolds for the 420 and the 560 to pick up quite a bit of top end HP.

Jim B. · #3 04-18-2007, 06:38 AM

Hi Dan,

This one's fun to talk about because I have not only owned a '91 560SEC for 10 years but also have taken a turn behind the wheel of a 400E and a 500E in the San Francisco area.....

As to the '91 560 SEC, I co authored a buyers guide at www.mbcoupes.com
which is fairly comprehensive. However it was back in 1999 so the remarks about prices are outdated now. Mine has Eibach springs and larger 16" wheels on it, and it handles a little trucklike at low speeds around town, the rear end is a little light, it can wash out if you go around corners too fast in the rain.

It saved me once at speed (70-75mph) going to Oregon, a flatbed truck in front of me
began shedding 55 gallon plastic drums all over the highway, they were bouncing all over the place and with the lowered 560SEC I was still able to steer my way through this unfolding nighmare at high speed without hitting any of them, most other cars it could not happen, so the car is VERY capable of high speed emergency moves, without doubt.

But, they REALLY shine at speed, (above 80 mph), they are rock solid and confidence inspiring. I have had it up to 148 mph for a few minutes on I-5 to Los Angeles, and the car really hunkered down, only difference was wind noise around the outside mirrors. After that, the normal cruising envelope for me felt perfect at 90-120 mph. Of course, it's at dire risk to your driver's license, in the USA, so I can't recommend it. But these cars were engineered to cruise at their top speed all day long. Gas mileage is nothing to write home about, I get about 12 mpg in heavy city driving, about 17-18 mpg on the highway. I always put Chevron Supreme with the Techron it has, in the car, to help keep the injectors clean, it has worked. At 118,000 miles, never a problem. Though at 100,000 miles, I simply had them changed as preventive maintenance, along with the timing chain, tensioner and guide rails, which should be done on these cars.

A couple of things I never mentioned in the buyers guide that I would add today. I would avoid any 560SEC with the ASR option (Orange triangle lights up on dash with these). ONLY the 1991 SECs had this "anti slip" there was no need for it, and its diabolically complicated to fix, and expensive too.

Also, check them carefully for water leaks, into the trunk (either through the trunk seal, taillight seal or worst, through the rear window. Around the rear window, (which is delaminating if you see milkiness in the lower corners) when the rear glass lets water leak in, the rust underneath starts, and it's a mess to fix.

In fact, check the whole car for rust. (Or any Mercedes you are buying.)

The nitrogen spheres (accumulators) were changed on the car twice in its life, not a terrible job. You will notice it is time when the ride gets VERY stiff and bouncy (or the fluid leaks out of them.) Motor mounts need to get changed every 50-75,000 miles, not a big job either. Unfortunately, the air conditioning/HVAC system is usually a problem on these cars, but KEEP the R12 in them, don't change to R134, it doesn't work as well and is not compatibloe with the system. Beru plug wires are good, as are ATE & Textar for the brakes and Rotors; BEHR radiators replace the originals, which had unreinforced hose necks (upper) which tended to crumble. It may be that BEHR radiators may no longer be so good as 10 years ago, if that is so then I would suggest NISSEN. Keep away from K&N air filters, no appreciable HP gain and they let more dirt in. (Buy OEM air filters.) Mann oil filters are fine.

So, basically they are good cars, if you find a good 560SEC that has been well looked after and unwrecked. They are tough buzzards, and will last for hundreds of thouosands of miles, the AT should last 250k normally before giving problems....It's worth changing the brake fluid and coolant regularly, as well as the ATF, using only Mercedes Benz fluids, not cheap substitutes.

Pay higher for one in good condition, (more important than actual mileage on the car) and get the best one you can afford.

I really like these cars, and would probably look for another, should mine be wrecked or totaled out. They still look really good, and are SO comfortable on long highway trips.

I tried a 300SE, and a 420SEL, and a 560SEL, successively, on the same route for extended test drives when I was looking. All are fine and feel exactly the same at highway speeds, but for highway passing and merging onto the freeway, predictably, the 300 is the slowest, the 420 faster, and the 560 fastest. The pedal throw is really long on them, and you need to mash your foot to the floor to get the speed they offer. I'm not sure of this but I believe the 300SE/SEL has a different axle ratio than the 560SEL, and I found the 300SE to be VERY quick in city driving.

The gas savings isn't that much, and the prices for these cars is not that high, so probably the 560SEC/SEL is the one to look at. But condition should trump all, it is the most important thing to get one in good condition. They seem to look best in the darker colors, dark red, blue, black, pearl black....

HIGHLY recommended are Euro lights and front sheepskin covers (fitted 2 piece NZ ones are expensive but really good I got from www.ramsheadusa.com). Upgrading to 16" wheels is OK, and the car looks nice with that, but to me personally 18" or 19" is just too big, though some people like the look and feel of the 18" especially with AMG monoblocks.

I had a test drive in an E400, and liked the car a lot. It felt REAL quick, handled nimbly, and was a real sports sedan. Since you have one, you know this well. These are a great overall car for reliability, handling, accelleration,
ease of repair, durability, longevity, and safety. I seriously was contemplating getting rid of the SEC for one of these at one point.

I also had a turn at the wheel of an E500. This isn't a Sport Sedan, it is a Super Car in Sport Sedan guise. It is a REAL hoot, and like a supercar, if you are not careful you can ge into some REAL trouble.

Within minutes behind the wheel, I was on highway 101 north of San Francisco, slicing and dicing through traffic at 115 mph, huge fun, the car was incredibly capable at that speed.

You can whip into a 35 mph corner at 60 mph and fgeel totally safe doing it.
The brakes are enormously powerful and haul the car to a stop REAL fast, more than your typical 300E or 400E.

A mint almandine red E500 I think might be about the only think that could tempt me away from my 560SEC.

560SEC,420E, and 500E, I think you are pretty on the same wavelength as I am with all of these cars, you could argue well for each of them, each have strengths and similarities, and ALL of them have their unique appeal.

I have been with the 560SEC for over 10 years, and I still like the car, which STILL has no squeaks or rattles when you go 90-100 mph.

If I were you, I'd try for some wheel time in good examples of each, and then determine which of them I would pick. A good example of any of them would likely be a good purchase and satisfy you well.

Whether you stay with a W124 or go to the W126, you are going to be getting a car with unarguable cost no object build quality, durability, longevity, safety, comfort, and old school Mercedes cachet. Find a good SEC/SEL, 500E/E500, or even keeping your E420, you'll be in a very fine car indeed.

Hope this helps, good luck

Jim

gmercoleza · #4 04-20-2007, 02:12 PM

Here's my quick and dirty opinion:

W124 (like your E420) = nimble, sporty, more performance oriented, more modern styling appeal
W126 = more comfortable (especiallyl for passengers), but less sporty, not as flat in the turns, harder to park, much much cheaper to maintain, very very easy to work on, styling beginning to look dated

I have driven both types for years so I speak from experience.