I JUST THOUGHT I'D LET A FEW PEOPLE KNOW THAT I HAD A LOT OF STARTING PROBLEMS WITH MY 380SL BUT THIS PROBLEM COULD BE RELATED TO ANY OLDER MERCEDES. MY CAR WOULD ACT LIKE IT WANTED TO START BUT WOULD SOMETIMES START IF YOU LET OFF ON THE IGNITION KEY IF IT STARTED TO ACT LIKE IT WAS GOING TO FIRE. I CUT THE POSITIVE CABLE RUBBER, IT HAD TWO COATS OF RUBBER AND A FINAL 3RD P;ASTIC COATING. AFTER PEELING OFF THE RUBBER ABOUT 4 INCHES AND EXPOSING THE WIRE I COULD
SEE CORROSION IN THE WIRE.I DUMPED SOME COCO COLA ON THE CORROSION AND WASHED IT OFF WITH WATER RECONNECTED THE
CABLE AND IT STARTS EVERY TIME.I'M STILL GOING TO REPLACE THE COMPLETE CABLE BUT THE CORROSION WAS CAUSING THE STARTER TO DRAW SO MANY AMPS THE CAR HAD TROUBLRE STARTING.JUST THINK WHAT THE COLA DOES TO YOUR STOMACH IF IT CLEANS CORROSION.I'LL KEEP YOU POSTED.

CHUCK D

 

a light coating of grease on the battery terminal can also prevent the corrosion.

anyway, it also happens to any brand of car once the battery is weak and spewing acidic fume.

i got very clean stomach for i drink at least two cans of coke daily.

 

Well I usually use coca cola to clean LMTV's battery terminals (Large military truck.). It does wonders. Never liked the taste though. But take some coke and add tarnished copper to it and the coke will clean it.
and what sleepwalker said works.
And if the battery is old, get a new one.

 

You mentioned a good point: if there is too much voltage drop during cranking, there is not enough voltage to get everything working; therefore hard or no starting. There is already high current draw by the starting motor, and there must still be enough voltage to make the computer and ignition systems work. Good battery, clean, tight connections, and cables/wiring/terminals in good condition are a must, especially on "electronic" cars.