Hi all I have a 2012 GL 450 I change the battery about four or five years ago I was wondering how long does it usually last I noticed the other day when I do start my car it’s slightly hesitates is that a sign that I need to change the battery

 

Hard to say. Lot's of variables. Battery brand/quality, use (and abuse) of the battery, etc, etc. That symptom "could" be a dying battery (likely), but it could be a corroded connection/wire, as well. Best thing you can do is to load test the battery. Short of that, slide the passenger seat forward and open the passenger side/rear door and expose the battery. Leave the door open and walk away from the car for 30 minutes and put the key back in the house. Come back and check the voltage directly at the battery (leave the key in the house). Do not open any other doors or touch any buttons.

 

You can get an electronic load tester for pretty cheap.

The starter becoming sluggish is a sign of age. Also, the starter wearing out will strain the battery, leading to a mutual downward spiral. It depends on the frequency of use, but if the starter is older than about 100k miles it is becoming a candidate for changing.

 

Ok thanks for the info

 

Hesitation is not an indication of a bad battery. The easiest method to check your electronics in real-time is to go to autozone or advance auto parts store and have them load test it with their device. Its free and they will give you a printout of what the actual values are.

With that said, the replacement procedure is pretty straight forward and easy, however, the space is very tight and you will have to wiggle your way around. The main battery is an AGM type and the secondary battery is a smaller auxiliary battery that also needs to be changed. Do both at once if you have to change one or the other. If you have to, buy the agm battery from walmart and the aux battery from ebay. That's what I did and both are holding up very good for the past 2 years.

If you don't have any check engine lights that are on or nothing out of the ordinary that occurred then I'd start there before paying out money to your local MB dealer for their diagnostic fee.

Side note...for the aux battery, if you go with the aftermarket brand, you will have to watch the connections as they are switched. (see picture for + and -) It's a very easy thing to miss so I'm just pointing that out now for future reference.

GL.

 

This may be hard to believe but my aux battery on my GL450 is the same one I've had since new. It's over 14 years old now. On my GL63 and as a point of reference, I had to replace the aux battery after 6 years.

 

If you're having hesitation after the vehicle has sat for a while, you may want to check fuel pressure on the rail. You could have a weakening fuel pump, or a pressure regulator (in the fuel pump assembly I believe) that is allowing fuel to drain back into the tank while the vehicle sits. Just one of many possibilities, but its cheap & easy to check.

 

my aux battery also factory when I pulled it out after 13 years of service…still holds 13.7 volts.

 

Speaking of changing the battery, when you're changing the main one does the auxiliary battery save all the radio settings and other gizmos ? Thanks, Will

 

4-5 years is the beginning of when a battery should be replaced. Hard starting or "hesitating" is a sign of the battery needing replacement.

Battery life in northern climates is shorter than in warmer climates. It's near zero degrees F in my neck of the woods and my W166 had its first tar-rar-rar-rar startup. There is a radio or audio program that is pretty funny along these lines. It features a guy imitating the sound of a Model T starting in winter. I searched google and didn't find it. Anyone know that one?

I plan to milk my main battery through this winter and replace both it and the aux battery in the spring. It will be 5+ years old at that point.

My previous vehicle was a VW TDI and I replaced the battery at 7 years but it started showing signs of decline a year or so earlier. I have always lived in areas with cold winter.