changing battery on w203 c class c270 cdi

[philepo]

Hi - am in a bit of a pickle. My battery was slurring like george best on wogan this morning and would not start. I need to change it but when I looked under the bonnet the battery seems to be completely covered by a plastic box that says (if I recall correctly) 'air conditioning' on it. I suspect it may be a cabin filter???? Anyway, I tried to undo the 3 latches on the top side, but it wouldn't come completely away, besides it was dark cold and lashing with rain so I thought I'd seek wise council before going any further.

Quick tips on changing this battery anyone? Cheers

 

[grober]

there is an elastomer [ sponge rubber] type seal between the air duct and the " cover" needs to be airtight as it forms part of the heater/aircon airducting. these tend to stick on to the plastics and have to be prised/wiggled gently away from each other.
[YOUTUBE]XyYq0eNroLE[/YOUTUBE]

ps watch the video to the end to see how the duct fits in place with the lower tabs

 

[Chrishazle]

To avoid voltage spikes (SAM's don't like them!), loss of radio code etc., before disconnecting the old battery, connect a spare battery to the "jump start" pos under the red cover, neg to the big suspension nut close by. Then disconnect the old battery (careful, the system is still live!!!) and install the new - then disconnect the spare.

I had my S203 C270 battery changed at ATS and had to teach them this trick - luckily I had a decent set of jump leads in the car, they had a spare charged battery.

 

[philepo]

thanks

great video, think I was being too gentle with it.

And top tip about having a spare power supply, I wonder if most garages know this?

many thanks

 

[philepo]

If I do loose the power, will I need to have the radio reset... will the alarm go mad etc??