Out of 6 month storage..
 

1989 560SL 95,000 miles.
I garaged the vehicle for winter and have just taken her out of moth balls and fired her up. Started immediately but soon showed signs of a very rich mixture....black sooty exhaust emissions. I thought when I took her for a run she might clear and start to run normal, but to no avail, it still emitted sooty exhaust deposits. I then purchased some injector cleaner fluid and put it into the tank to see if that might help and then ran her a couple of miles, but it does not seem to have helped so far. Question now is; Will it need more running to clear it and if it doesn't would I be doing any harm to the motor or components? :confused:

it might clean out if you drive it fifty miles or so. but you dont want to run it that way long term. it will dilute the oil and may ruin the bearings.

tom w

...not good for the catalytic converter either, if so equipped...

Glad to say the injector cleaner and a nice 38 mile freeway run has got things back to normal. Next storage, will definately add fuel stabilizer into tank before putting away. I suppose a monthly start up would do no harm either. Thanks for your replies.

I've read the WORST thing to do when a car is in storage is to start it up every month or so. Better to leave very little gas in the tank, change the oil, disconnect the battery, and let it sit. When eventually starting it up, get some fresh gas in the tank and change the oil.

As a longtime boater in winter-cursed Michigan, I've used the same strategy for my Benz (and the old Mustang I had for 12 years before it) that I learned eons ago. Fill the tank, so that you minimize condensation of water which will settle to the bottom, and add stabilizer; drive a ways after doing so to make sure the stabilizer's gone through the whole system all the way to the injectors; and I leave a Guest Marine battery maintainer type of charger hooked up all winter with the battery in the car. Both the Stang and now the Benz always fired up with no problems every spring. I *don't* start it during storage, as the last thing you want is condensate from combustion in the oil and the exhaust system without getting up to full temp for a while to dry out. We used to fog the marine engines but that doesn't seem a good idea with the sensors and catalytic converters our cars have now.

People who know more about fuel chemistry than I do tell me that modern fuels, especially regular, start losing octane in even a couple of weeks and stabilizer is more important than ever. I use it routinely in the gas I have for lawnmower and snow blower, since those cans can sit for a while, unless the two-stroke oil I'm using has stabilizers included in it.

Interesting comments that will be my guide this fall....we learn from our mistakes and hopefully next Spring all should be okay. Thanks all for responding, much appreciated :)