merceBENZ

I will need to unhook battery for coolant change and seatbelt repair. I know that this is quite complicated process to reset all sensors plus conver roof. Could somebody tell me which exactly sensors I will need to reset and how? Can I leave unhooked battery for a week? I will send belt for repair. How do I close/open door with window in full up position?
Seems like an extra after project.

Rudeney

After disconnecting the battery, you will likely need to reset the window positions, which is easy - just lower each one halfway, then hold the switch to raise the glass, and then hold the switch for 5 seconds after it reaches the top. Sunroof is the same. Sometime you need to reset the ESP steering wheel position sensor. To do this, start the engine, and while in park, turn the steering wheel fully lock to lock about three times.

You may also need to reset things like the clock (unless you have COMAND, in which case it gets the time from the GPS). Other things may include you bass/treble settings.

As for opening and closing the door without the window dropping, it can be done, but it does put extra stress on the glass and seal, so be careful.

merceBENZ

I have soft top instead of sunroof.
1. What do I do in this case?
2. Will I get error codes? Someone somewhere mentioned that they got lights on dashboard after disconnecting.
3. Can I keep it unpluged for a week?
4. Can I keep it unplaged with window in "open door" position?
5. What is about clock by the speedo?
6. By any chance, could you describe how to reach coolant drain bolt on crank case and what kind of hose do I need to buy? Pictures on STAR are junk on that topic. I don't get where that bolt is.
7. Should I change coolant anyway even if I way under what MB suggests on mileage and age?
Thank you very much for your help.

Rudeney

1. There is no re-sync necessary for the soft top.
2. You should get no errors codes (other than the possible ESP error if the steering position sensor needs a re-sync). However, be careful not to "stutter" when disconnecting and connecting the battery lead. You will get a small, benign spark when you do this, but stuttering and letting it create a shower of sparks can damage things.
3. You can keep it disconnected for as long as you like. Mine recently sat unplugged for three weeks while I had the transmission out with no problems. Some people who store their cars for months at a time leave the battery disconnected.
4. Yes, no problem. If you are in a garage with no worries about theft or weather, you can leave the windows down. Just remember that the trunk latch is electric , so with the battery disconnected, you will need to use the hard key if you need in.
5. If you have COMAND (NAV), the clock is set by the GPS, you just need to select the correct time zone and turn DST on/off via the COMAND settings. If you do no have COMAND, then the clock is set via the steering wheel buttons and menus on the instrument cluster MFD.
6. Why are you using the drain on the engine block? There is a suitable drain on the radiator.
7. I would follow the maintenance manual's schedule. Change it when it's time, either by miles or months. Make sure you use the proper fluids! Zerex G-05 is a suitable aftermarket coolant. Prestone is not.

JimVonBaden

I would just connect a motorcycle battery before removing the main battery. I have a few sitting around. Not sure if it works on these cars, but you can get a plug for the cig lighter that will maintain 12V for a short period of time too.

merceBENZ

Point of battery disconnection is prevention of airbag deployment and coolant from crank case can flood electrical stuff. But it brings inconvenience of those resets. Mine field.


6. Because this is what manuals says. This is proper procedure. Though way more complicated...
7. Should I wait another 5 years then? Miles are far beyond reach.
I was going to use genuine MB fluid.

Rudeney

Interesting - I never paid attention to the instructions, but there it is - drain the block. I have always just drain from the radiator and gotten over 2 gallons, so I figure that was good enough. But yes, I'd wait until it's time.

merceBENZ

I will wait then. I problem less! Thanks!