I have a mint condition 500 that I am thinking about buying. The guy I am buying it from said there was major work done to the engine and is like new. I currently drive a 99 lexus es300. Should I? Or shouldn't I? I've read that the early 90's had many problems and I know most everything is expensive. Would it be worth it?

 

The search function is your friend.
Unfortunately since the w140s are such old cars now, most of them have exchanged hands several times over and are nearing if not passing beyond the 200/300k mile mark.
There is no objective answer to your question. They were over engineered cars and are basically civilian tanks with a badge from a prestigious car maker; but again, like most anything that exchanges hands several times over, things get neglected. I wish i could tell you with a straight face 'YEAH! Go buy it now!' but i cant.
Yes they have had issues with certain things (wire harness, mirror wiring corroding, misc issues involving vacuum lines), but overall they are well made cars. Personally speaking, since I own two, I can tell you its my favorite body style. I don't care if they're older. I drive a 2013 suburban and also own a 2007 Audi a8, but i still love my w140s. I consider myself an expert on the 97-99 w140s but cant say for the pre-97s.
Ask for proof the work was done, ask for maintenance records. Mercedes is the type of car where if you dont keep up on the maint. it will bite you in the *** later. yeah you can keep it going with duck tape and glue, but so can you with a Hyundai. Though the parts for the merc are 3, 4, maybe 5 times more expensive. The w140s are complex vehicles and need to be tended to by someone who has been around them. Sure oil changes and regular maint can be taken car of by the normal joe the mechanic on the corner shop down the street, but some issues need to be tended to by the inde shop for older euros.

all that being said, I just have to say theyre great cars if taken care of right. take it to an inde shop, throw a 100 bucks at them and ask them to go through it with a fine tooth comb. 1992 merc is 20/21 years old. 20 years! its been through a lot in that time; dont buy a ticking time bomb. if you want a mercedes for the sake of having a mercedes, and are willing to get an older one (which it seems youre okay with), get a 98ish c280. theyre like go karts, run forever, and theyre 5 times less complex than a w140, and theyre better on gas; theyre like european honda civics, cant kill them if you tried.

 

Thank you. The merc has 130,000K but I have read that the early 90's mercs have the problems that you mentioned over and over. I still am going to check it out and drive it but after what you said, research and what my car friends said I may back away from this one.
How much would a 98 c280 run for?

 

Im not sure. 3-5k? whenever one of my 140s would be at the shop id get a 90s c-class loaner car. very peppy and go-kart ish. I liked em a lot. the only reason i wouldnt get one now is i dont have the room for it and i have enough cars in the stable as it is. I guess the next car id want is a convertible, but even then.. trying to stay away from older cars for reasons i mentioned earlier.

1996 LX450 modded for trails and overland trips (lockers, camping gear, winch, the whole bit).
2007 a8l used for everyday stuff and occasional trips to the mountains when meeting people for snowboarding. just throw on the snow wheels and its set.
2013 suburban, the people mover, and group taker to the hills, and trips to home depot.
1997 s320 and s600, the garage babies that I like a lot for no realistic reason.
1991 acura integra that had the suspension, engine and transmission overhauled and setup for SCCA and other track races.

none of these id give up for another car (actually the a8 id let go for something different if the right car popped up....1994 e500??).