petaling

2010 C250 4Matic
only 7000 kms or 4000 miles driven short commutes wkdays only.

Temp recently minus (-) 10 Deg Celcius snowing.(14F)
Car would not start one cold morning.
Called MB Roadside Assistance. contracted Guy came with Battery booster pack hooked up outside the actual battery on the red post and ground and car started.Since then drove it around more distance and car seems to start ok.

At rest after car cools down ,red auxillary post outside battery on driver side shows 12.25 V.
Turned engine on same posts (outside battery) reads 14.6 V

Is this 14.6 V too high and the 12.25V at rest too low,bearing in mind it is belowing freezing temp outside? Should I ask for a new battery with the next service ??? Is there anything diff with this supposedly newer 74 AH AGM battery?

Thanks for any advice.

Carsy

Your voltages in my experience are normal meaning your battery is holding the charge & that your alternator is charging as it should.

I think that the problem may have been your short trips are not allowing your battery to charge sufficiently . Then it is asked to start a very cold engine partially charged.

I suggest that just in case you have your battery load tested at your local auto electrician or battery shop.

Also if you are to continue with the short trips I think fortnightly top up with a trickle battery charger may be in order ( say over the weekend). C Tek is a recommended brand.

These batterys seem to have a service life of over 8 years so you would be unlucky if it is failing.

The AGM, Absorbent Glass Matt battery is the MB recommended battery & with a life of over 8 years are worth the money.

Good luck.

Carsy

kevink2

I fully agree with Carsy. If car is close to that temperature for a morning start, an engine heater is advised. Also, this is exactly why they list Castrol's 0W-30 as an approved oil.

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petaling

While engine heater is quite common in Manitoba where I lived be4(up to minus 40 C= minus 40 F that is where Mr. Fahrenheit met mr Centigrade occasionally)
it is very uncommon in Ontario,
eg airport carpark in Manitboba has electrical outlet for plugging in the engine heater but you'll never find these in T.O.