Dead Battery in 355

Buy an Optima redtop battery and CTEK battery tender--You will never have problems again...

 

+1

 

Probably any Group 34 or 34R battery is fine if you use a battery tender religously, and top up the electrolyte once per year, which is a pain, because of the location. The best battery (in my opinion and Consumer Reports) is the Sear Platinum in Group 34. It is $190 and is an Absorbed Glass Mat battery very similar to the Optima, but even more powerful (rated at 880 cold cranking amps). Totally sealed, and no liquid acid to leak out. Never needs water either. 4 year free replacement warranty is the best in the business.

http://www.sears.com/shc/s/p_10153_12605_02850034000P

 

buy a standard battery. then buy a battery tender. you will be very happy. any battery will go dead by sitting. by "tending" to the battery you are keeping it at peak performance. looking at a price of about a 100$ for both.

 

purchasing both together will be 100$. not 100 each.

 

I have never had a flat battery in ether of my 355's,

My car came fitted with an "alternator"

This device is used to keep the battery topped up.

It is a fantastic bit of kit, simple to use, just start the car and drive it.....

 

+2

 

True, but AGM batteries can withstand sitting for much longer periods of no use, than a standard battery. Also, AGM batteries have a much longer service life as well. When you factor in the lack of requiring to add water (not easy on a 355 with the difficult to access location), buying an AGM battery that costs twice as much, but has zero maintenance and potentially twice the service life can make it a cost effective solution.

Both Optima and Sears Platinum have been top rated by Consumer Reports the past two or three years now.

And if saving money is important, pretty much any battery tender will do the job just fine, including the Schumacher battery tender, that sells for about $30 at any WalMart store.
I have 5 or 6 different brands, and they all work fine....just make sure it says "battery tender" or "smart charger" or "microprocessor controlled" or "fully automatic"...all work great and will not overcharge. There is even one sold at Harbor Freight Tools for $10 that several users claim works fine as well. Only problem with that one, is it only comes with clamps to connect to the battery, not convenient on a 355, so you will need to make up some ring mounts and run the wires from the battery up to the trunk to connect up.

 

Another option is to use the smaller Mercedes battery. It has the tangs that engage the chasis brackets. It is a tight fit but I installed one on a friend's 355 this last summer. I have also used the Merc battery in my TR. Good luck!

Jeff Pintler
89 348tb, 86tr, 99 360 Manual
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+3

 

Jeff, what are the reasons for using the Merc battery?

 

She will run like new when Brian gets done with it

 

I like the Mercedes battery because it has the mounting tangs that lock into battery tray, not just the small bracket with the bolt. The Interstate and Sears batteries do not.
The big tabs in the picture are on all four sides of the battery. FWIW.

Jeff Pintler
89 348, 86tr, 99 360 3pedal

 

We are really not replacing them. The alternator and starter are being rebuilt. Rather unusual for a starter problem in a 355 but the solenoid is very weak. Alternator problems, especially in the early 355 is not unusual.

 

Well at least the car will be all sorted out when you get it back.

You can always sell me your wheels to offset the cost

 

Do they replace the solenoid with a better unit now days or its the same solenoid that goes back on that starter Brian?

Is the 348 and 355 starter motors the same?

 

I really don't have an answer for either question right now. The shop I use goes to great lengths to use the latest and greatest parts and up grades whenever possible. The stuff is being deliverd to him today so I have not heard back exactly what he is going to do with it. The starters have not really been problematic so I do not know if better parts are called for or available.

It's been so long since I personally held a 348 starter I don't know. Thats the kind of question to ask a parts guy.

 

Too easy mate, thanks for the explanation.