I loved my 420SEL and it gave me about three good years with no costs other than fluid changes (it was already 12 years old and had almost 200,000 miles on it when I bought it). But after the third year stuff started to go, and not because of any problem that is specific to the car, but because it was old. It started with the shocks (which I was surprised to find out were the originals) and the exhaust system (parts alone were a couple of grand here, not including the cat converter). Secondary air pump came next, some bushings for the front control arms, and then I developed a bit of a shake at idle. I too was told I needed a valve job at the very least, but I had poor compression in number 8 cylinder and given that I had already spent 8 grand on the car that year, I figured I could lease a used one with a Starmark warranty for what I was paying in repairs (got my '95E420) and I ditched it. They still gave me three grand for it against my lease at the MB dealership, not bad considering I only paid about 12 for it (Canadian$).

I really loved that car, and it never let me down. Any of those things that were replaced gave me signs about 3-6 months before they gave out, so I was never left stranded anywhere. The ride was amazing. I would love to get my hands on another one of those. I'm not too mechanically inclined so I had most of the work done at the dealer, but I did do some of the easy stuff and found the car was easy to work on. If you do your stuff its really the parts and the time that will cost you. Don't settle for the first one, there are still plenty of these around, and you never know, spending an extra couple of grand up front on a better kept car may save double or more in the long run.

Good luck.

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Jason Priest
1999 E430
1995 E420 - retired
1986 420SEL - retired