Opinion of a 1989 Mercedes 420 SEL ?

Question

I stumbled across a very clean, very smooth running 1989 420 SEL. One owner. 210,000 miles. Timing Chain changed at 110,000 .. It starts on the first grunt of the starter, less than a 1/2 second. No ticks, no leaks, no smoke. All maintenance logs, interior clean (not detailed to make it just look clean). The only odd thing is when I checked the oil, it looked very clean and I smelled it. It had a smell that I associated with a failing motor... hard to describe, but thin, almost like oil and hydrocarbons mixed.

I know that timing chains should be changed every 100,000 - But the 210,000 does concern me. I also heard if the chain snaps in these, you can bend a valve? Is that true that the 1989's had interference motors?

Thank you in advance for your opinions.

Answer 1

with an older mercedes, miles are not nearly as important as maintenance history. if a car like that has been kept up, it can go 300k+, no problem. have it checked out by a mechanic who specializes in these cars. that will get you farther than anything you could do yourself.

Answer 2

The worst problems with the W126 timing chains were fixed with a dual gang chain when the 420 motor was introduced in '84 or '85. The older 380 motor had a single gang chain that could snap and you would get bent valves. This is far less likely with the dual gang chain and is likely to give more warning. Have the tensioners and idlers checked and a new timing chain might be a good idea after 100,000 miles. A workshop that knows what they are doing can replace a timing chain for several hundred.

Look out for oil leaks around the head gaskets, this is a bad sign.

Can't comment on the oil. It might be a recent change and who knows what brand it is. Gasoline in the oil might be from
worn rings - a compression test might indicate this, or it could be from one or more injectors dripping pressurised fuel on standing. This might be indicated by reluctant starting after an hour or more standing but it is not usually a big problem.

A slightly rough idle is no indication of big problems, it is common with all W126 motors and there are several web sites that tell you how to fix it, it isn't terribly difficult.

Problem areas can be air conditioning, the switches, hot water valve and the rubberised flaps inside can give trouble.
My older coupe uses the Delco compressor once also used in GM cars, these are still easy to replace.

Make sure the transmission shifts cleanly, the W126 transmission is not really smooth even when in it's finest condition and you can feel the shifts. Any noise from the differential is too much.

The rear suspension is complex but repairs to the usual problems are not terribly expensive.

The radiators can break off at the top hose connection, but later models had a metal reinforcement here if it is a genuine Behr. If the engine temperature indicates over 90C on ordinary running get it checked. These cars usually run at 80C on the dial and I have only seen 90 on mine on a hot day with a howling tailwind.

A lot of minor problems with these cars are user-fixable. For instance you can pull the window switches apart, clean them out and put them back in. You can also pull the cruise control apart, resolder the circuit boards and they will work again.

There are also a lot of good wrecker parts and new old stock parts available.

These cars are great to drive, the 420 was probably the most economical on fuel but they are getting a bit long in the tooth.

Answer 3

This Site Might Help You.

RE:
Opinion of a 1989 Mercedes 420 SEL ?
I stumbled across a very clean, very smooth running 1989 420 SEL. One owner. 210,000 miles. Timing Chain changed at 110,000 .. It starts on the first grunt of the starter, less than a 1/2 second. No ticks, no leaks, no smoke. All maintenance logs, interior clean (not detailed to make it just look...

Answer 4

1989 Mercedes

Answer 5

Mercedes Benz 420sel

Answer 6

420 SEL is a good car! But, as with any used car, have it checked by a Mercedes mechanic. If the owner doesn't want you to take the car to YOUR mechanic, you do not want this car.

Answer 7

the first order of business before you buy any older car is do love it enough to feed it parts over the long haul? the above answers on what to expect should help with your decision, but remember once you start putting money in an old car you will never be able to resell it for a profit. should an accedent ocur the insurance company will only give you what they say it is worth this being said i hope you do purchase and have fun with it for a long time THESE ARE GREAT CARS

Answer 8

GREAT car when it was new. But a pain in the neck to maintain if you want to make it a daily-driver. If you want to buy it just for weekend drives, then do so after you check it out with a mechanic. But as I said, with 200,000+miles, this car could cost you more than you paid for it just to keep it running. GOOD LUCK.

Answer 9

If its got all the maintence records and the price is right go for it. I just sold my 560SEL with 151,000 on it for 4400 so dont let the guy sucker you. I have also owned a 300sdl and loved them both just sold the 560 to free up some cash no other reason!

Answer 10

Change chain every 150,000 miles.Engine good for over 400,000 with oil changes.