W220 is on my short list of cars to consider. However, I do ALL my own work no matter how difficult. That means no matter how torturous the job, I'm going to be doing it. Originally, an 04-05 Audi A8L was my 1st choice, but I have researched those cars thoroughly and found that the timing belt is a HUGE job (shops charge around $2k, mostly labor) which also involves removal of the entire front end of the car, and that's considered the easy part. I would be okay with that since the belt has a 100K change interval if it weren't for the fact the water pump and thermostat are behind the belt. Those items should be replaced with the belt, but if either of those items fails to match the belt's 100K interval, the entire job has to be repeated. It also requires expensive specialty tools. Sounds like a DIY nightmare.

I'm aware the most common issue with the W220s is airmatic. It seems parts cost is high, but labor is easy. I've seen many people on this forum say they changed their own airmatic struts and it wasn't bad, and I've seen tutorials for ball joints and inner tie-rods which looks very straight-forward. Are these jobs also easy on the 4MATIC version? Am I correct that water pump, thermostat, and most normal wear items are all pretty straight-forward to change with basic tools? Are there any common issues that are a DIYer's nightmare? I don't mind a car that isn't the most reliable as long as the problems don't leave me stranded and the repairs are relatively easy. It's my understanding that the S500 engine and transmission should be pretty solid and relatively reliable.

I absolutely don't want something where common wear items are near impossible for the garage mechanic to fix. Where the first step for removing the starter is "Remove engine and transmission assembly" or the first step for changing the serpentine accessory drive belt is "remove front end of car", both of which is the case on a W12 Audi A8L!

 

If you are as mechanically competent as you say you are then you will save yourself thousands on labor. Of course you will need a service manual and diagnostic tools to read codes. Parts are not horribly expensive but when you add labor charges, repairs become scary.

 

the common failure items on a non-ABC w220 are not too hard for DIY

 

Correct. Struts can be removed quickly and with only a few hand tools, oil changes are easy, and overall, the car is well engineered and laid out. It's a very serviceable car. The only real issue is not having Star Diagnostic hardware, which is what the dealer uses to check all the systems and whatnot.

For reading engine fault codes (check engine light) a normal OBD II code reader will work fine. I have the mid level $229 Accutron unit that I got a few years ago when I had my Volvo. Works great on the Mercedes too!

This is all on my 2001 S 500. I don't know much about the 4matic. It's all the same though minus suspension and drive line.

Ewwww, Audi. Talk about a real pain in the ***. My ex girlfriends 2001 VW is 10 times the headache as opposed to working on my S class.

 

Its not too bad at all. The mechanicals are robust, pretty easily accessible, and the steps to fix things are pretty logical. Keep in mind that with any german luxo-barge, you will be removing plenty of covers, shields, and insulation to get to stuff. Thats just the nature of the market. Not hard, just a bit time consuming.

Since you seem to abhor going to the dealer, you may want to consider investing in a SDS system. They are expensive, but with that, there is really no reason to go to the dealer.

The 4matic doesn't add much complexity to this car, unlikely say a 210 E-class.

I've had my car 2 years, and haven't had much to do mechanically. Just some minor niggling electronic issues.