I had (and am still having) some issues with my 420sel and I thought I would post my findings for future reference for any members who might be interested.

The car:
1988 420sel
235,000 miles purchased with 220,000

The issues:
1) Suspension: The rear sags a little. Judging from pics it looks like the ride height is about an inch too low, and it leans slightly towards the driver's side. Also, when braking the front wheels vibrate and overall the suspension is really sloppy. When driving at highway speeds a spirited crosswind makes the trip very eventful. Driver's side front tire also shows some uneven wear.

The fix:
Replaced rear shocks with Bilstein HD's, also rear springs were broken (causing the sag) and had those replaced along with rear stabilizers. Rear ride height has now been corrected. Flushed brake fluid and turned rotors. Replaced front strut rod bushings and steering stabilizer bar. Had a four-wheel alignment done as well.

2) Engine: Upon startup the engine stumbles and shudders noticeably. Rough to irregular idle. It gets particularly bad when driving in the 1000 to 1500 rpm range, until the engine warms up to about 80 degrees celsius. Then the engine accelerates and runs fairly normally. Sounds like there is some cam noise on the right side.

Possible cause: Camshaft needs replaced. Already had one mechanic say that's what needs replaced, will look further into this before I pull the trigger. It won't be cheap.

3) A/C: No A/C. Receiver drier might be shot. Needs to be charged but this might be tricky as it originally used r12 freon. Will look into Autofrost as a replacement.

Will look into this probably after I have engine issue fixed.

Verdict:
I can honestly say this is the best car I've ever owned. Yes, I'm going to have some expensive repairs into it, however once these are done the car will be good for another 100,000 miles. It is in excellent shape for as old as it is and for how many miles are on it.
About 2 months ago I considered selling it and buying a newer car. My job consists of driving around 400 to 600 miles a week, and I thought a newer car would be a wiser decision than putting money into a car that isn't worth it. I'm glad I didn't because I just got laid off!

But here's the reason I love this car:

Insurance: $30/ month
Car Payment: $0
Fuel: Between 20 and 22 mpg
Reliability: Second to none

Even with current gas prices, it is STILL cheaper to own and operate than a new car. Plus, I have the opportunity to learn how cars work (not a natural gearhead) and increase the amount of repair I can do myself.

I will post further updates as they happen for posterity.

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1988 420sel

Ok, the car drove well but it seemed like the steering was sluggish. Checked the power-steering pump and it was leaking badly. Replaced pump, problem solved. Also, for some inexplicable reason, the car seems to run smoother.

Right side of the engine sometimes shudders badly upon startup. Darn camshaft.

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1988 420sel

I also think these old Mercedes are a lot of fun to own and operate, and if one can learn to do his R&R, operating coast are not bad either. It is tough to get on top of one that has been abused for many years, but we should have the smarts not to buy one like that.

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Junqueyardjim
Christianity, if false, is of no importance, and if true, of infinite importance. The only thing it cannot be is moderately important. C.S. Lewis



1983 Mercedes W123 240D 4 Speed 285,000 on the road with a 617 turbo, beautiful butter yellow, license plate # 83 240D INDIANA

2003 Jaguar Type X, AWD. beautiful, good mileage,
Mom's car, but I won't let her drive it!