Hey guys I'm new here and wish to learn everything I can about my car and how to make it better.... I have a few questions to start off:

1. Oil changes: my scheduled oil change is on February 7 or 51700 miles and its currently February 16 with 50700 miles. Should I go ahead and get the oil change? just the date mean anything or is mileage more important? My dealership does my oil change for like $20.

2. Gumout: does anyone use this stuff to improve gas mileage? is it a gimmick? I fill up my car at Shell and I believe they have detergents in the gasoline. If so would getting gumout be a waste since Shell is doing the same thing?

3. Warming up your car: its cold where I'm at. I'm talking 7 degree weather. Does it help at all to let my car run for 5 minutes before driving or is that an old wive's tale. I usually take my car to around 5000 rpms merging into traffic in the cold morning...not sure if thats recommended?

4. engine breaking: when I'm going down a huge hill can I put it into neutral or is that detrimental? how about if I keep it in gear making the car slow down?

thanks for all the help guys!

ps I bought this car used so all the aftermarket mechanical stuff was done by the previous owner.

 

2) Don't trust those things.
3) 1 - 2 minutes is enough, but drive slow for a few miles.

 

that was helpful. thanks. anyone have answers to my other questions?