HiTach

I'm getting ready to store my new baby for the winter and have made a checklist to share, plus looking for any additional tips.
I plan to keep this vehicle for the long term and don't need three cars on the road, so the S550 goes into cryogenic hibernation and my MLs get to drive in the snow and rain for which they do a fine job.

1. Storage location
The vehicle will go in a dry secure location unheated but with a concrete floor, power available for trickle charging. Some people need to protect against rodents and other pests by using mothballs, rat poison and maybe plugging up the exhaust tips.

2. car cover
I bypassed the $300 Noah fabrics used in the MB OEM and other top quality covers. I don't need wind and weatherproofing, so I got just a dust and ding barrier. The one I chose from eBay [link] was a 4 layer cover with a semi-custom fit (no mirror pockets) but at 1/5 the price it does the job. The cover also blocks the air vents and other entry points for pests.

3. Trickle charger
My SA advised getting a 3rd party model rather than the MB badged device, and in my research I found the MB product is manufactured by CTEK, a Swedish company. The matching model is the CTEK 3300 . I got one and it works as described. My charger came with both medium sized crocodile clips as well as a short connector to bolt on to the battery terminals with a quick disconnect and a rubber protective cap on the other end. This allows the adapter to be left permanently bolted to the terminals and easily disconnect the charger. The CTEK model also works for motorcycle batteries. It has circuitry to detect the battery condition, recharge to full as needed and cycles on and off to maintain the charge over the long term. I got mine from Amazon for ~$70 [link]. The MB product is around $150 but also comes with a 12v socket adapter which is an optional $10 accessory from CTEK. The manufacturer page is here.

Thanks to other posts and the vehicle manual I have gathered that the starter battery under the hood can be disconnected and should hold enough charge through the winter, though a little top-up from the CTEK before starting may be beneficial. The real charging protection serves the "consumer battery" located in the rear behind the back seat for safety reasons. This battery serves all non-starter electronics and maintains the seat memory and other custom settings.

The consumer battery terminals are also under the hood just next to the starter battery beneath a black cover around 10" long. Pinch the tabs to release the clips and wiggle it off. Here is a picture (Thanks DieselBenz!):



On my 2008 S550 only the two outer cables are present. Connect the positive charging lead to the tall brass post, the negative to the other (outer) lead, then connect the charger to the mains supply. I have been testing on my ML500 for a few weeks and it seems to work fine, alternating between green (full) and orange (pulse charging) blinky lights.

4. Fuel stabilizer
My SA recommended adding Sta-Bil to the fuel and driving it around a bit to mix before storage. I have read a full tank of fuel reduces condensation, but some locations require a maximum of half a tank. At 1oz per 2.5 US gallon the 10oz treatment works for the full tank.

5. Tire pressure
I was told +6PSI to each tire to prevent flat spotting.

6. Insurance/registration
You will probably want to keep coverage for fire, damage and theft. In PA we are also required to keep liability insurance on state registered vehicles, even if they are not driven on the road. For "mature" drivers this may not be a big cost, but those with teenage drivers on the policy may want to avoid this by transferring the plate between summer/winter vehicles or using seasonal registration.

7. Kiss and wake up
Giving the vehicle a good clean and a polish inside and out before you put it away will minimize scratching from dust under the cover and help you fall back in love when you wake her up.

8. Before you hit the road
Leave a note to yourself with a list of what to do when getting back on the road (reduce tire pressures etc.)

Please feel free add any additional tips or corrections.

IDriveAnM5

This is just about identical to my list of storing my M5 before the winter - the S550 is my year-around car.

I store in a spare spot in my garage. It is parked on top of carpet squares to further prevent flat spotting. I also inflate the tire pressure by +6 PSI.

My car cover is a little bit better, as it is semi-fit with mirror pockets. I also have a locking cable that I attach to the nearest wheel. It isn't necessary because the garage is secured and alarmed, but I do it because I have it.

My trickle charger happens to have BMW written on it, but I know it is a Deltran model, and goes on with alligator clips to the terminals under the hood. I close the wire into the hood, making sure to wrap the wire in a soft, thin cloth to prevent contact with the body.

I always store with a full tank of gas - I've never used fuel stabilizer in all the years I've been storing cars, and I've had no adverse affects.

My cars are company cars, and in Ohio, you're not allowed to reduce the insurance coverage if they're stored for the winter. Basically, the insurance company assumes that, since it is a company car, it is on the road 365 days a year. Not true, and expensive, but something I have to live with.

For the M5, I always give it several coats of Zaino Polish before storage. I also detail the interior, cleaning and conditioning the leather in all places as I go. The wheels get cleaned inside and out, and I give the carpet a shampoo (letting it completely dry) before storage.

I also keep a list (radar detector, Blinder, tire pressures, etc...).

Good advice!

HiTach

Nice company cars!

kingofire

Hi HiTach,

Yes I do believe you need to change the oil especially at 4000 miles. Normal OCI is 5000 miles nowadays so since you already have 4000 miles, I would change it as the TBN(The Base number=active life remaining in oil) is probably half of what it is new. This means that the TAN(The Acid Number) is also half of what it would be new. All the blow by from the piston, exhaust and seals are in the oil settled on the bottom of your oil pan just eating at the oil pan metallurgy. It is better to be safe than sorry in this situation. If you are not planning to keep this car long term(>5 years) than let it sit and have it be someone elses headache. JMO.

HiTach

Thanks for the reply Kingofire.

Do you mean that the Flexible Service System monitoring which recommends approximately 10,000 miles between services is actually double the life of the oil, even with Mobil 1 synthetic?

"Since 1998, all new Mercedes-Benz vehicles are equipped with the Flexible Service System (FSS). An electronic monitor checks the quantity and, on the advanced version in our new family of V6 and V8 vehicles, the condition of your engine oil. A "wrench light" on your dashboard lets you know when it's time for a regular maintenance service.
While each Mercedes-Benz is precision-crafted to exacting standards, not all drivers are alike. The Flexible Service System (FSS) accommodates the service requirements created by your individual driving style. By constantly monitoring your engine oil, the FSS may extend the service interval, which averages about 10,000 miles, without sacrificing the performance and protection you expect from your Mercedes-Benz."

In any case, as you suggest, better safe than sorry as the car will be stored for about 6 months. One of the reasons I buy Mercedes Benz vehicles is because I expect to enjoy them for a long time. I have had my ML320 for over 11 years now and my whole family still loves it.

kingofire

Hi HiTach,

I am pretty sure 10K miles on Mobil 1 is doable but this all depends on your driving style and patterns as well. For example if someone like me who does 90% city driving, there will be a lot of soot, blow-by combustion and fuel build up in the oil hence me changing it out at whatever miles it has at the 1 year anniversary as MB recommends.

Since you have 4000 miles and the oil has say 40% acid build-up(TAN) in the oil, you don't want it to sit for the entire winter and this acid eating up the metallurgy of the oil pan and the light film left on the rocker arm, cam lobes and shafts.