My 2008 S550 is one of the most satisfying cars I ever owned. I bought mine a few years ago at 95K miles and it is at 115K miles now. I am assuming you are on this forum because you are not afraid to wrench during the weekends. If you do your own work, you can save a ton of $$$ by not going to the dealership or mechanic. This forum has a lot of good info and help. It has been a pretty reliable car for me, just do not abuse it, like any other car.

Aside from the typical maintenance items such as changing out all the oil, filters, and fluids regularly, replacing spark plugs, tires, brake pads, brake disc, belt, hoses, ball joints, light bulbs, etc. It has been a pretty reliable car. You do not have to worry about the worn idler sprocket in the engine, for it has the newer, harder gear.

The following items are specific to the S550 and will eventually need to be replaced/repaired, such as:

• Driveline rubber flex discs (2)
• Airmatic struts (easy to replace)
• Airmatic valve block (the cause of most suspension problems, easy to swap out)
• Airmatic compressor (easy swap out)
• Soft-close latch switch replacement (see my write-up soft close door latch erratic )
• Front-seat air bladder replacement (little more involved)
• Side mirror motors (easy swap out)
• Oil cooler and oil filter housing gasket change (easy)
• Intake plenum swap out (due to dirt/carbon build-up over the years inside. You could clean it out as an option)
• Engine and transmission mounts (easy to replace on the driveway)
• Wrinkled center console armrest (easy fix)
• Clock-setting issues (search work-around)

It is also a good idea to get a Mercedes-specific scanner. This one is a good one and can scan 59 computer modules in the car. See:

Amazon.com: Professional Multi-System Auto Diagnostic Tool iCarsoft MB V2.0 Compatible for Mercedes-Benz/Sprinter/Smart, ABS SRS Oil BLD INJ : Automotive

Shop Amazon for Professional Multi-System Auto Diagnostic Tool iCarsoft MB V2.0 Compatible for Mercedes-Benz/Sprinter/Smart, ABS SRS Oil BLD INJ and find millions of items, delivered faster than ever.

www.amazon.com

This one is a bit cheaper, smaller, and scans about 53 computer modules. I keep this one in my car. See:

Amazon.com: 2017 GENUINE iCarsoft MERCEDES BENZ i980 PROFESSIONAL DIAGNOSTIC SCANNER TOOL : Automotive

Shop Amazon for 2017 GENUINE iCarsoft MERCEDES BENZ i980 PROFESSIONAL DIAGNOSTIC SCANNER TOOL and find millions of items, delivered faster than ever.

www.amazon.com

And don't forget to get a good service and repair manual. I got mine from here: 2008 MERCEDES S-Class W221 Service and Repair Manual
It is about 454 MB, 7,000-page PDF download and I think it is a scan from the Mercedes Benz dealership workshop manual.

I don't think you will be disappointed with the car. 😄

 

You are already an MB owner so that helps with your understanding of the cost of upkeep of these vehicles. Anyone can buy a Mercedes, but it takes some who has attention to detail, patience, a little and good tools (if you DIY) to maintain one.

its is like dating a super model, they are very beautiful, but need your undivided attention. If you do that, the car will reward you for many many years (not sure if a supermodel would lol).
Heed well of what Jagpilot said, many people think a Mercedes is a tank, they are, but they must be maintained.

if you are willing to spend time with the car…get it, love it and enjoy it. We are all here to help you if you do decide to purchase it.

One note, if you like to tinker, be aware of plastic bits on the vehicle in the engine bay. I like to put my hands on my engine a lot (sometimes just cleaning and touching). This has resulted in broken plastic bits that are small but are attached to important stuff. I have had my car down for days at a time while I scrambled to get replacement.

 

I bought my 2008 in 2017 with 110k miles on it. Since then I've put 72k miles on it which would have been 110k by now if not for the pandemic. It is easily one of the best cars I've ever owned. Yes as mentioned by @Jagpilot and @kawagirl there is maintenance required, however your experience with the R107 means you understand the value of preventative maintenance.

And the plastic bits, yep, a bit of a pain and even more so here in the desert where summertime temps are >100F from June through September. I do not think there are weak points on this platform if you respect the complexity of the car.

 

Bought my 2008 S550 three years ago, probably my twentieth Mercedes, Some day I gotta sit down and make a list of them, it might be my 22nd. Excellent car. I miss the super thick windows of my W140, I don't miss the issues I had with my W220. MBZ wanted to get back to the solid W140 feel after the W220 and I'd say they got it right. The 2008 S550 is a really great car. Previous owner hadn't reset the odometer computer in the dash so it shows 19.9 MPG average over the last 30,000 miles, Hiway/City combined, not bad really for a big sedan. Mine has 137K miles and after an oil change, go six months without checking the oil and it hasn't used a drop. In the old days a car with 100k miles used a bit of oil and you had to check it frequently. Fairly trouble-free and the spark plugs are easy to reach to change yourself. Years ago I had a car this fast, which the S550 is a pretty fast car, back then the car I had got half the gas mileage. Beautiful, comfortable, safe and fast. Great for picking up dignitaries at the airport! I really love this car. 14 years "old" still looks like a newer car, and everything on the car works perfectly. Original cost over $100,000 new, and I paid $12k three years ago. Who wants a Lexus!!

 

Thanks for the thoughtful responses, and you all make it sound like a pretty reasonable option and not likely to be the money pit that the uninitiated caution about. I also have a good feeling that the 221 is one of the better S-class iterations, and I love the looks. I'll have a talk with this fellow and see what I can work out. Thanks a bunch and maybe I'll be seeing alot more of you around here.

 

My friend bought an 07’ s550 and has all kinds of gremlins going on but insists on fixing it himself instead of Mercedes Benz.mind you he makes $180,000 a year as a truck driver.

 

The #1 rule for me when I buy used Mercedes (15 to date) is that I'm buying someone else's problems. Almost no one parts with a car because it's running fine, but have to say working on these cars is very much about the fun of the engineering. How it comes apart, how it goes back together, totally worth the time you put into them if you do it right. Half-efforting something will come back to bite you.

 

I started with Mercedes ownership about 23 years ago when I had spare time on weekends and I bought a 1980 R107 450SLC because the ad said "Steal This Car". Lady was selling it for the amount a dealer was giving her on a trade-in, which was next to nothing. Car was beautiful and fantastic, it had one problem the front brakes were metal to metal. New front rotors and pads and the car was literally like new. A nearly free mercedes! Next one was cheap too because it had an issue, the flex discs were shot, and I mean really bad. How could any driver keep going until they got so bad? Got that car fairly cheaply as well, spent less than $300 having new flex discs and driveline bearing put in (This is 20 years ago), the car was near perfect. At least ten more Mercedes followed bought cheaply with all of them having one problem that the owner found to be insurmountable. A fuel distributor for a W124 300E cost about $2500 at a dealership, I found one in local ads from a college student selling car parts, for $100. All those Mercedes had one problem, and after fixing I'd driven them at least a year before selling and moving on to another, I was amazed at how simply and cheaply most were repaired with a little imagination and bookwork. Lot of help here on Benzworld. It's true some cars are junk with a whole bag full of problems, but I never got one of those. Even after I no longer needed to buy cheap ones, I still stayed around the $10k-15k price range. Then always replacing engine and trans mounts, full tuneups and oil and all filters change, and then mostly just drive and enjoy for long periods without further issues. In my Mercedes experience I could not be any happier! Whenever I get another Benz, I expect to do mounts the first week! This way, you know they are new. It's good to have a local shop that knows the cars so you don't have to go to a dealership if an issue arises that's too much for the home garage.

 

OP, you seem to be well suited for the “W221 experience “ prior MB ownership is quite helpful. However these cars require updated tools and some wrenching skills and you can enjoy a world class sedan. Hi way cruising,,if you think Autobahn required capabilities suit your need go for it. If you can plan and pay for “normal maintenance “ items as Jagpilot points out so very thoroughly, you will enjoy. Do your due diligence there are 1st year model issues related to engines.

 

 

Get the engine serial number and make sure it is higher than serial 2739 30 088611

The M273 engine was also affected by the cam chain sprocket issue more commonly referred to as the “balance shaft issue” on the V6.

 

Wait: Higher is bad or higher is better?

 

How would you know if a lower engine number was or was not corrected?

 

I bought my '08 six years ago with 25k miles. I now have 61k miles and haven't had to do anything to it other than engine oil changes, transmission fluid, air filters and a blinker light bulb.

I suspect I'll have to do engine mounts at some point. I get some vibration at idle. The engine mounts in this car seem like a really poor design...they all fail, yet what's the upside for giving up reliability? My Chevy Silveratdo and my Corvette, both with V8 engines, idle more smoothly, with no need for engine mount replacements after 13 and 22 years (and a fair amount of heavy acceleration).

My driver side seat lumbar air bladder loses air pressure every few days. Not worth replacing yet, as it does hold for a few days, then I just pump it up to my desired setting.

Go for it

 

If you have an engine from 07-08 with a serial number showing it was affected with the sprocket issue, a dealer could look in their computer to see if it was corrected under recall coverage at any dealership. There's also a website somewhere where you can look up by VIN and see a lot of a car's maintenance and repair history.
vehiclehistory dot com and it's free.

 

A couple years ago I picked up my first MB - a beautiful low mileage 1985 380SL and joined for forum. That cars has been a dream to own and I'm considering doubling down in this MB lunacy.

I know an MB matchmaker of sorts who is offering a 2008 s550 RWD from cali, 1 owner with 115k, I don't think it is highly optioned as I get the impression that the original owner was a little frugal. This car looks beautiful and I'm assuming was never abused, it is also mechanically sound as of now - no open issues or lights. The price range is in the $10k-12k.

I'm considering this as a daily driver and highway cruizer. I really like the looks of this year, and I've read that some of the 550 engine problems were sorted out this year.

Any thoughts on this? Is this going to be a total money pit, or am I likely to get a few nice years out of it and then move on with only modest depreciation.

Anything I should be aware of (besides the rising cost of gas ) as I consider this arrangement.

Thanks guys, and maybe I'll be seeming alot more of you soon (or not.. if I'm lucky )

Like my 2010 S550, but the gas mileage is worse than my 04 S600.

 

Modified parts are installed on engines as of engine # 30 088611 so anything below is, or could eventually be affected.

 

A couple years ago I picked up my first MB - a beautiful low mileage 1985 380SL and joined for forum. That cars has been a dream to own and I'm considering doubling down in this MB lunacy.

I know an MB matchmaker of sorts who is offering a 2008 s550 RWD from cali, 1 owner with 115k, I don't think it is highly optioned as I get the impression that the original owner was a little frugal. This car looks beautiful and I'm assuming was never abused, it is also mechanically sound as of now - no open issues or lights. The price range is in the $10k-12k.

I'm considering this as a daily driver and highway cruizer. I really like the looks of this year, and I've read that some of the 550 engine problems were sorted out this year.

Any thoughts on this? Is this going to be a total money pit, or am I likely to get a few nice years out of it and then move on with only modest depreciation.

Anything I should be aware of (besides the rising cost of gas ) as I consider this arrangement.

Thanks guys, and maybe I'll be seeming alot more of you soon (or not.. if I'm lucky )

I really like my S550 however, I got better fuel mileage with my S600.