Buying a used W210 is just like buying any other 12 year old car.
If I was buying another W210 tomorrow, first things I would pay attention would be;
Fixing rust most of the time could be expensive, spring perches could be a safety issue, a transmission without a proper maintenance history could give you some headache.
Engine and well maintained tranny on these cars are known to last for a long time without any major issue. Head gasket problems on modular engines are almost unheard of.
Spark plugs, cables, vacuum hoses, breather cover cleaning along with a new MAF and O2 sensors every 100ish K miles as well as some here and there small items(CPS etc), thats all you can do for these motors, of course regular oil changes... When I say oil, remembered that these modular engines tend to seep just a little bit from the rear main seal, not a big big deal unless you have a little puddle on your garage floor.
Regular maintenance of drive belt system is just like any other car if not easier, harmonic balancer issue is fixed after sometimes mid 2000 if I`m not mistaken, a good quality tensioner cost somewhere between $100-150 online, idler pulley was $55 at the stealership last time I asked 6 months ago and I got the pulley from RMEuropean for about $18 or $20.
Transmission`s achille`s heel is the pilot bushing and ATF wicking up into the TCM but this issue and any other transmission issue(conductor plate, solenoids, speed sensors, shifter module, liquid spills etc) is very well covered here at the W210 stickies. These are really rugged boxes( especially after 2000) and it takes some really stupid actions to hurt them.
Climate control is little tricky but still compare to a lot of other "modern" idiotic designs easy to work on, at least the basics, if something more complicated, then I`d take any car to a professional when it comes to climate control anyway.
Ceilings tend to rattle in these cars a little bit with the age and driving habits, this one is also covered in the stickies.
Pixel issue is well known and also covered here.
Headlight lenses tends to get yellow over the time, some elbow grease, cold beer&good quality cigar and some good music in a saturday afternoon will solve that problem.
Blower regulator blew on me 2 summers ago when it was 107F outside, asked the stealer, it was ridiculous $360, it was $88 online but I didn`t want to wait, got it from an auto recycler for $30, he even let me install and try it before I buy it, so far so good since then.
Engine and tranny mounts are the items you should keep an eye on them maybe every 3-4 years, of course that also depends on your driving habits and mileage.
Within the same family I like the V6 engine better than the V8, it is easier and cheaper to operate and maintain, of course that`s just my 0.02 cents.
Good luck on your search.
Thank you very much blackhawk, that's very helpful.
It's hard to tell by reading forums if something is really a common problem or not because, as the old saying goes, nobody complains when nothing's wrong.
I chose the W210 after searching & reading as much online about different models reliability and comfort. I've always liked it's styling & interior; so it seemed like a good fit.
The only thing I'm worrying about is if I overlook something which could cause problems which domino into an expensive issue. I have at max a $15,000 budget; but I'd like to stay below $10,000. So my plan was / is to find a well cared for W210 with no rust & have all of the aging parts which will inevitably go bad over time replaced with fresh new parts.
I do have another car (cheap little late 90's toyota corolla) which I purchased, after selling my previous car, as a stopgap to the W210. I plan on keeping it as a backup car, but taking the insurance off & using the W210 as my daily driver. The corolla is in good condition & will probably go a long time with no issues, but it's an ugly little car & has no character; not to mention annoyingly loud on the highway.
So that's my story, hopefully that gives an idea of what my intentions are.
Since I'm learning as I go, and haven't really worked on any cars (most of my mechanical knowledge is from reading books, diagrams, forums); I'm not very confident about my ability to see the whole picture. I know that a Mercedes, even an older one can cost big money if something major happens; and I want to take every precaution against that.
When I finally get one, I want to get it in as tip-top mechanical shape as possible within my budget, and baby it as I will try to keep it for at least 10 years.
Hopefully my assessments have been accurate & I'm not living a pipe dream.
What are your guys' opinions?