I new to the oil talk world so my ignorance may show a little. I have been doing my own oil changes for 42 years on various vehicles. I have a company service van that is required to be serviced through a vendor. The vehicle is a GMC 3500 with 167,000 miles. The dealer switched oil from semi to mineral based and changed the brand back 30,000 miles ago and the last 20,000 I have had a tappet noise at start up or piston slap as they call it until the engine warms up. Recently i purchased my own oil and bought some Mobil 1 filters because we are now required to change oil every 6,000 miles instaed of 4,000 miles. I bought several kinds that were on sale and was trying to decide which one to use. I have 7 other vehicles that require with different uses so the oil are custom for each engine.
1.)Two of the vehicles are Park Ave. are my older and used by college age sons.
2.)One is a Chevy G30 diesel 1983 RV in great shape with low miles.
3.)One is a 2005 Lacrosse I bought used with excessive wear or care.
4.)One is a 1995 Toyota with High mileage and runs excellent.
5.)One is a John Deere tractor with a 17hp. Kawasaki engine.
6.)One is a 1969 Vintage John Deere Tractor 2020 I to plow snow and move round bales. The engine was completely rebuilt 5 years ago by a guy that does high end tractors.
The oils on hand at this time are
Shell synthetic Diesel 5w40,
Mobil 1 5w30,
Mobil 1 extended 10w30,
Mobil 1 5w30 High mileage,
Mobil 1 10w30,
Amsoil Diesel 5w40,
Walmart High Mileage synthetic 10w30,
John Deere synthetic 0w40,
Mobil 5000,
Penzoil 5w30 Platinum
Observations made and random thoughts when I switch to the JD 0w40 synthetic my tractor turned over and started up when it was 20 below 0 without help or labor for the first time.
The oil life indicator on the Lacrosse suggests changing my oil at about 6000-8000 miles.
The little JD gets 0w40 and a Mobil 1 filter also and is air cooled.
My sons cars get whatever I have left or bought on sale or Farm and Fleet oil until I had a engine problem on one which now has Valvoline 5w30 with a Mobil 1 filter.
The 6.2 Diesel has Farm and fleet synthetic diesel 15w50 in it right now.