Considering high mileage S550 136K to be exact. What should I look out for on a higher mileage cars? Also how’s the reliability on these S550, if it’s been maintained properly. Also I know most if not all are on air suspension, given the age how long/miles they topically lasts? Thanks in advance.

 

The S550 is a reliable vehicle. Airbags on any Benz vehicle typically last about 10 years /100k miles; very few reports of them leaking on the W222 because it’s still relatively new. Coolant lines can leak, suspension bushings wear, but other than that there are no common issues.

Good luck!

 

Suggest you verify the major service items have all been done ... engine mounts, suspension bushings/ball joints, transmission fluid & filter, spark plugs, driveshaft flex couplings.

 

M278? Hears my experience with a w221. Same engine... Bought at 70k miles. Currently at 100k miles. DIY. BTW. Vacuum pump. Turbo coolant line. Had to reseal the timing chain covers. Rtv. No gaskets? MB. Lol. It doesn't burn oil. I am thoroughly impressed with this engine. AFAIK it only got better in the W222. If your looking for perspective look at TT BMW V8's.

 

I'm also interested in buying a Mercedes-Benz S550 with M278 engine. However, I was told by many that I should not buying a car with a high mileage because they said they didn't know how the cars were driven before and turbos could be a major problem and replacing them could be a fortune .Other than that, whoever I confer to say M278 is a great engine

 

Need all the service records. Compression test the cylinders. DIY engine removal for turbo replacement not too bad.I have so much confidence in the m278 I am looking for a W222 coupe.....

 

my experience has been they seem to go through brakes around every 30K miles or so other than that pretty reliable.

 

You just need to keep in mind your buying a 100k+ ar new that has higher miles and so fixing it will be a lot more than if you bought a Honda Accord with that mileage. MB parts are expensive and even indy mechanics that specialize in MB are more than the usual mechanic out there. If you have a guy you trust to look at i would I would spend the $$ for a deep inspection and also review all records.

 

I did the spark plugs on it too. Lots of room. I did have to replace a coil pack on Cylinder 5. Need to keep an eye on the cam sensors for oil leakage into the wiring harness. MB Air suspensions seem to start to have problems at the 10 year mark. That seems to be the consensus among MB techs I have talked to. I did have problems with a CV boot on the passenger side inner front axle. I bought the CV boot kit and pulled the axle out. Noticed the differential seal was "sweating". Replaced that.

 

They are very reliable. But where the car is from makes a big difference in some reported maintenance. A northeast car with harsh winters, cold starts, potholes, and salt is a very different car than Florida, Arizona, and Texas. A well cared for southern car looks new at 100,000 miles. Just as different underneath too.