Experts weigh in, please; '91 420SEL

[Abner Mality]

I am to look at a 1991 420SEL, on Monday. It is a one-owner, Arizona car with 109K miles. Dealer claims to have all service records with the vehicle.

I intend to try to purchase for somewhere in the $6-6500 range. I need a quick course in this model Benz with as much good, bad, and ugly as you feel like providing. Previous or current owners, techs, please help me in this.

TIA

[sokoloff]

Never owned one and don't know them that well, but I seem to recall that there are plastic oiler tubes that deteriorate and must be replaced or you're looking at damaged camshafts. I understand that it is a very cheap and easy fix and ought to be a routine maintenance item. Maybe others with more info can chime in on this one.

Len

[Snibble]

If I were you, I'd hold out and find a 560SEL. One can be bought at the same price range.

[suginami]

I'm pretty sure the "oiler tubes" affect M119 engines only, not the one in the 420 or 560 SEL.

[Messier11]

Originally Posted by Snibble

If I were you, I'd hold out and find a 560SEL. One can be bought at the same price range.

Why snibble?
Something wrong with the 420SEL? They look identical to me, except for the 5.2 liter in yours?

[Nipperiley]

I would take the 420 over a 560 any day, the difference in power is not that much. Plus you don't have to deal with the possible problems with with rear hyd shocks. These were a hard ride from the factory, and expensive to fix if there is a problem.

On a 420 you can just change the shocks for a part cost of less than $200. for OEM shocks.

[Hatterasguy]

They need the timing chain and rails done every 100k like clock work. Don't try and put this off on a M116 or you will be looking for a new engine.

If no record of them being changed comes with the car plan on spending $500-$1k right off the bat.

Other then that basic W126 problems that have been talked about to death. Rust shouldn't be an issue with an AZ car.

[Snibble]

Originally Posted by Messier11

Why snibble?
Something wrong with the 420SEL? They look identical to me, except for the 5.2 liter in yours?

Only the outside is same.

Inside and under the hood its different. The 560 came with all the luxury options and had burlwood as opposed to zebrano. The engines on the 560 are a little more lineant on timing chain tensioners breaking than the 420. Oh and the 560 has a 5.6L not 5.2.

[Abner Mality]

Hatterasguy says: "They need the timing chain and rails done every 100k like clock work. Don't try and put this off on a M116 or you will be looking for a new engine."

I've read a few hundred posts re timing chains, and I am under the impression that the 420 has an M117 engine. This timing chain issue reminds me of the many "oil change" threads; not much agreement to be found.

Does the M117 engine have the double chain? Is it the chain, the rails, or the tensioner that should be the more-closely monitored? Obviously, if I'm to go with the aforementioned vehicle, I'll go through all the records, and just as obviously, will not want to take any chances for a TC failure, but don't want to spend unnecessary money, either.

One thread I read through suggested to line up TDC on #1 cylinder, and check to see if the cam tower mark lines up with the mark on the gear as a way to check stretch. Theory being that no stretch meant no problem with the TC. Later in the same thread, it was suggested these double-row (if that is what the M117 has) are virtually bulletproof from the factory, and that the tensioners were all that needed to be replaced at the 100k interval.

Where is Larry Bible when I need him?

Thanks for all the commentary, and please keep it coming.

While I'm at it, what kind of fuel consumption am I to expect on the 420SEL?