Originally Posted By: Quattro Pete
Originally Posted By: Indydriver
Wondering about trying M1 0W-40 but concerned about winter cold starts.
Why would you be concerned about winter cold starts with M1 0w-40? It's perfect for that.
Thanks for the response and encouragement re: M1 0W-40. I have a couple of OCs worth in the garage and I'm looking for an excuse to try it.
The reason for my concern is that my car is parked in an open air garage at work and is subject to 0F and colder starts during our cold Indiana winters. If MRV -40 is the best test for cold starts (and if you've got a better one, I'd love to know it), 0W-40 is over twice the viscosity of 0w30 (31,000 vs 13,250) and the specified 5w30. That seems significant to me and I certainly don't want to diminish quick circulation of cold oil in this turbocharged engine.
OTOH, my UOAs show significant fuel dilution at 3,000 miles. So, even though I have plenty of TBN left at that usage, the viscosity is down in the xxW-20 range. Mazda is concerned about minimum viscosity in this engine as they recently issued a warranty extension on the turbo and timing chain only if at least xxW-30 oil is used. So my thought process is that 0W-40 would keep the viscosity up but clearly the 0W with the 40 is higher than the 0W viscosity in the 30.
To boil this down to my question, do you think that the higher cold viscosity of M1 0W-40 will cause more start up wear than 0w30 or 5w30?
Also, I'm looking for a once-a-year oil for this car as I only put 4-5,000 miles per year on it, but with lots of short trips (i.e., 4 miles one way to work).
