JALLEN4

It has been very cold with temperatures around zero for the past two days. My ML 250 sits outside and on the second day would not start. When the starter engaged, you got a high pitched whine very similar to what you get starting a turbo prop airplane. It turned over but no start most every time except a couple of times when it would start but the whine would occur and it would die immediately.

Five hours after calling, Mercedes Roadside showed up to tow it to a dealer three miles away. In the process we tried again to start the vehicle and it did start. I drove it to the dealer and left it to be looked at. This morning they tell me they found a low battery voltage fault and replaced the battery. I picked it up and it is operating fine but of course it is warmer today. Anybody have any thoughts on the actual problem or does the battery sound plausible?

kajtek1

High pitch whine is starter motor turning, but starter sprang clutch or gear not engaging. Doesn't really sound like symptoms of bad battery, but you've got new one anyway.

JALLEN4

I agree the new battery is great. Your take on the starter is mine as well. Could cold or ice cause the starter to not be able to engage?

kajtek1

Cold weather usually magnify weak points. Sprang clutch uses centrifugal force to move the gears against the spring. But it is all in balance without much margin for play.
Thicker grease on gears in cold weather definitely is not making things spin easy.
Than you can have several things going with similar symptoms. Still remember communistic Skoda I drove years ago.
1 winter I had problem with turning over the engine. It was intermittent, so I started with replacing solenoid, than it went starter clutch, than at the end turned out my ignition switch was acting as well.
Thing are definitely easier to troubleshoot when they simply die, but having 3 things making intermediate problems in single system took me 2 months to solve.