I have a 2000 Eldorado ESC with 107K miles. I have recently developed the cold knock when first started up. Once it begins to warm up the knock goes away. This only happens when it is very cold outside. It is winter here in Ohio. Summer time I don't have a knock. Yes I have read the service bulletin about the combustion chamber deposits. I was thinking of going to the 0W -30 weight synthetic from a 5W - 30 weight synthetic. My questions are: Will the 0W - 30 silence my cold knock? Will I damage my engine using 0W - 30? Would the 0W - 30 increase the combustion chamber deposits? Thank you.