I have noticed that the W211 320CDi has sometimes taken longer to start, especially when not used for a number of days.
Sometimes it is almost instant, other times it may take 2 seconds or so before it fires up.
The glow plug light extinguishes quickly, the fuel pump can be heard to prime the fuel system so I am leaning towards a battery that needs replacing, and having just checked the battery voltage I saw 12.14V.
The car has however not been used since Friday when it covered around 15 miles and has not been used much for the last 10 days.
I tried to look at the date stamp on the negative post but it is unreadable, there is a label on the battery which is an MB-supplied part but am unsure if this number also relates to any manufacturing date?
The label reads A 005 541 10 01 as per the attached picture.
The battery is a fairly standard 019 type of 95AH and 850CCA, I am unsure if it is an AGM or not but the car does not have Stop/Start but I think AGM or conventional Lead plate type are both suitable. I have found several retailers online selling what seems to be the identical Varta battery (AGM ) for £175 which is reasonable.
My question is are OE MB batteries any different from the retail versions apart from the MB Logo? I intend to give the car a run tomorrow and see what the voltage is overnight but I feel a replacement is due anyway.