At what "oil life %" do most of you change oil, after the 1st oil change? And is it true that the more WOT, the more frequent the change?

 

5K miles

 

I change the oil at 0% (starting with the very first oil change) because the oil life indicator is a conservative estimate. GM says to use the oil life indicator (with time and mileage restrictions) to maintain your warranty so you can bet when it says 0%, there's more left in it...no way they would cut it that close and subject themselves to additional warranty costs. The more WOT you do, the quicker you "use up" the oil life. The 'Vette I race is asking for an oil change now after less than 1500 miles...but about 300 of those miles are race miles with many, many trips to 7000+ RPM and mulitple bounces off the rev limiter at 7100+ RPM. I have 50K miles on that one and it just keeps begging for more racing. The other 'Vette has 117K miles and it runs just like new. I've been using 7500 and now 10000 mile oil change intervals since the early '80s and haven't had one single engine failure with many cars over 100K miles and three over 200K miles. All engines had just as much power/oil pressure and MPG as when new.

In addition to WOT, higher oil temps, higher engine temps, higher RPM, and short trips (especially less than 3 miles) will negatively impact the oil life indicator percentage. But the system monitor all that and require more frequent oil changes. The one thing the system can't monitor is the amount of dust in the air. If you live in a particularly dusty area, you'll need to change oil at 3K miles and don't go by the oil life indicator.

Obviously I believe in the oil life monitor but some people have a hard time letting go of old habits. Oils are light years ahead of what we had in the '60s/'70s and so are engines. As a result, we don't have near the maintenance on cars today. Like tune ups...before we changed plugs and points every 12 months/12K miles if not before. Then there was the cap/rotor/wires to worry about. Today a tune up consists of changing the plugs at 100K miles...essentially we don't even think about doing tune ups anymore. Having said that, if you want to change before you get to 0%, that's your choice if it makes you feel better...you won't be hurting anything. Just know that you won't be gaining anything either. The only negative is your time/money that it costs to do earlier oil changes...to each their own.

PS The technology is already in place for 30-40K mile oil change intervals. It'll be here sooner than later.

 

Most synthetics are good for 15K+ miles. I am very conservative and have chosen a 6 mo. or 6K schedule; I don't care what the DIC says.