From my 1992 Chevy Suburban 2500 w 7.4L engine. 57,000 total miles on unit. Truck spends most of it's life in a garage. This M1 10W-30 was at least a few years old before it went in August, 2011 - I think it was API SM.
This truck went 5 years between changes, but only 1781 miles. Most of the miles are short trips around town - less than 20 miles round trip - it did take a trip or two down to Va Tech pulling a small trailer - maybe 3-4000 lbs total - 500 mile round trip, but not in the last 3 years. Most of the truck's previous life was spent towing a 12,000lb race car trailer and running M1 15W-50. This short mile OCI saw a few ounces of make up oil a few years ago. Lead is only # I see that's even semi-high and I'm not concerned about it. TBN still strong after 5 years, it's possible I could have gone a few more years. I did not change the oil filter as it still looks brand new - on the outside - filter is an AC Delco Professional. I will change the filter at the next OCI 5 years from now. The truck was refilled w M1 0W-40 - it holds 7 quarts. This truck is not driven in the snow and rarely sees rain. My takeaway from this report is...if you're using a quality synthetic and don't drive much with a garage kept car, annual oil changes are likely a waste of time, money and resources.
This truck went 5 years between changes, but only 1781 miles. Most of the miles are short trips around town - less than 20 miles round trip - it did take a trip or two down to Va Tech pulling a small trailer - maybe 3-4000 lbs total - 500 mile round trip, but not in the last 3 years. Most of the truck's previous life was spent towing a 12,000lb race car trailer and running M1 15W-50. This short mile OCI saw a few ounces of make up oil a few years ago. Lead is only # I see that's even semi-high and I'm not concerned about it. TBN still strong after 5 years, it's possible I could have gone a few more years. I did not change the oil filter as it still looks brand new - on the outside - filter is an AC Delco Professional. I will change the filter at the next OCI 5 years from now. The truck was refilled w M1 0W-40 - it holds 7 quarts. This truck is not driven in the snow and rarely sees rain. My takeaway from this report is...if you're using a quality synthetic and don't drive much with a garage kept car, annual oil changes are likely a waste of time, money and resources.