jtb33

Bought a new-to-me 2012 E550 Coupe with the Bi-turbo V8 engine. It's got 116K miles on it, but it is in excellent condition mechanically as well as the interior/exterior. Everything works, etc. 1-owner car prior to me. I bought it from the individual who bought it new. Got all service records for it since new. It was always serviced at a dealership (originally in WA, and then at ~50K miles, the orig owner moved to CA, so it was serviced at MB dealerships there afterwards). The service records show regular and meticulous maintenance including the 10K, 20K, 30K, 40K, (etc) service interval maintenance, all the way up to 120K interval maintenance, despite it not being at 120K when that was done. It appears to have had no major work done on it per the records and notes.

The car seems to have pretty much all the options: heated/cooling seats, the AMG appearance package, harman/kardon audio, etc. Luckily, no airmatic suspension on this (not even sure it was an option on this year). If I am being picky, I found a nick in the paint on the front bumper, the front rims have a small bit of curb rash on the area that touches the tire (not in the middle), there is a small crack in the "wood" trim on the passenger side just above the glove box, the radio's 'skip/forward' button has worn through, one part of the driver's seat leading edge is 'cracking' (more on that in a sec) and the driver's side arm-rest pad has cracking in it that's about the size of a quarter. Oh, and it's missing the MBZ logo on the plastic engine shroud (looks like it fell off, as the circle in the middle is there, but empty). That's about all I can find.

Here are my questions:

1) The seats are not coming apart, but on the leading edge, the leather is beginning to "crack". It hasn't torn yet though - is there anything I can do for preventive maintenance on this? If it matters, these are the black perforated leather with the heated and cooling seat options.

2) The COMMAND radio/nav system. The car has the harman/kardon system in it, if it matters. I'd love a radio that has Android Auto, but don't want to lose out on the OEM features like the backup camera, steering wheel controls, etc... and the radio head unit has several buttons connected to it like the sport mode, the rear sunshade and the heated/cooling seats. Is there no option to retain all that and 'upgrade' the radio system? How about the monitor?
Would this work: https://www.carputech.com/products/w...1650fda5&_ss=r
What OEM functions would I sacrifice - if any - with that?

3) Anything else I should know or check for? This is my second MB. Previously, I had a GL450 that I drove to 230K miles before the engine gave out.

ibbij

Congratulations on your purchase. I have thoroughly enjoyed my same year and model E550 coupe.

Here's the majority of the things I did for it: https://mbworld.org/forums/e-class-c...cessories.html

And here's how the ceramic coating came out: https://mbworld.org/forums/e-class-c...ting-e550.html

More recently put the new tires on it: https://mbworld.org/forums/e-class-c...lin-tires.html

I also bought it at higher mileage and you will want to get an inspection done of your suspension parts, coolant lines (they will break because they are made of plastic), and if the seatbelt presenter becomes finnicky, its likely not the motor but the control box that goes out. I bought a used one on ebay and it's a straight plug and play replacement so not a lot to do there.

Best of luck to you and hopefully our M278 turbo engines go the distance. I've put about 20K miles on mine since getting it a couple years ago, it's a fun car to drive.

jtb33

Thanks. How much did it cost to replace the plastic coolant turbo lines?

ibbij

The parts are not that expensive, the labor will be at least $1-2K. The parts should be roughly $60-$90 each and there are four plastic coolant lines.

https://mbparts.mbusa.com/v-2012-mer...and-components

If you have no coolant in your coolant tank and/or warning saying low coolant chances are the coolant lines are ruptured.

jtb33

Thank you for the comments. I've got some updates. There seem to be no leaks on this car except one (will get to that in a sec). The coolant is blue and is full - no leaking. This was a one-owner car and I pulled the carfax. It has 15 pages of history from the owner servicing it at several dealerships. I called each of the dealerships that had serviced it with the VIN and spoke to a helpful service manager at each one. With the last 8 of the VIN, they looked at the history of work at their dealership to see if:

1) the turbo coolant lines had been changed
2) the camshaft position sensors had been changed
3) or the adjuster magnets had been changed

The most recent dealership said that the owner brought it in in April of 2022 at about 95K miles with a coolant leak in the front, and they confirmed it was from a ruptured coolant line. They said they "changed them". I didn't want to press - and likely the service manager wouldn't know - but my question was if they just changed the ruptured one, or if they changed out all of them.

None of the dealerships had any information on the camshaft sensors or magnets being done. So today, I pulled one on each side of the engine and saw that they had the green O-ring, which suggests that they've been replaced. One of the connectors had a minor amount of oil on it.

1) Do I need to change the camshaft position sensors again?
2) How can I tell if the magnets were also done?

The only leak the car has is at the bottom of the washer fluid reservoir. I assume it might be a grommet or o-ring... or maybe one of the hoses to the light washer that has come off. It leaks pretty quickly and empties out within a few minutes.

ibbij

I don’t know about the camshaft position sensors or adjuster magnets because I have not done them but will ask my mechanic this week to check.

I had to replace my windshield washer reservoir because it had a crack and completely emptied last year. Also replaced the lower radiator hose because hose/clamp no longer sealed properly. So could be possible you may need a windshield washer reservoir.

ibbij

Here’s a post about the sacrificial harnesses. I will see if I need to do this.

https://mbworld.org/forums/e-class-w...age-issue.html