[hau101]

I used to commute in the City (San Francisco) for 6 mi in stop and go traffic and changed oil in 6 months according to the "severe" service schedule before getting laid off and now drive it about every week, also about a few miles each way but try to squeeze in a pass through the highway to get her up to speed (most drives are at least 10 min long). It's been 2 months of daily driving since the last oil change, and 3 months of weekly driving. Would weekly driving still require a "severe" oil change schedule, or can I do with the regular yearly oil change? I use synthetic oil.

 

[MichiganMike]

You live in an area with a relatively mild climate, which is not as demanding on engine oil. However, short trips of less than say 15 minutes may mean the engine oil does not reach normal operating temperature for long enough to prevent some moisture from engine operation collecting in the oil and compromising lubrication. Be aware that it takes longer for the engine oil to reach normal operating temperature than the coolant.

The discussion at the link below may be of interest:
https://forum.miata.net/vb/showthread.php?t=103493

If you are using synthetic oil as Mazda recommends, this will help to prolong the oil life. If it has only be a couple thousand miles since your last oil change, you should be able to stretch oil change intervals to closer to normal duty intervals without significant risk. You should have the oil changed at least once each year regardless of mileage. I change the oil in my Mazda every 5,000 to 6,000 miles, if this occurs in less than a year.

 

[tots]

Since your driving conditions are variable, I would recommend using the 3's oil life-remaining monitor. You probably don't want to wait all the way till it reaches zero, but it can serve as a guide of how your particular driving conditions are reducing the oil's usability.

 

[RalphVa]

I'd go to once/year changes.

We've a Tacoma pickup that we only put about 2k/yr on. When it gets driven, it goes for 20 minutes each way. I only change the synthetic oil in it about every 3 years.

I've a diesel generator that only gets run 15 minutes every other week. I plan to only change the synthetic oil in it about every 6 or 7 years. Changed it at the 50 hour mark (after 3 or so years), and it was hardly colored at all. This is a DIESEL, which normally gets more soot into the oil.

Ralph