I'm trying to decide on my next oil change in my 1976 Oldsmobile 350 V8. While it was parked for winter I had mmo soaking in the cylinders and the dosed the oil with it also so I'm currently running a short oci with conventional 10w30 cheap oil....
I've always ran 5w40, 10w40 or occasionally 15w50. It's had very low oil pressure since I put it in the car 12 years ago and 100k miles and it hasn't changed noticeably.
The oil pressure is almost low enough to scare me with 30 weight (4-6 psi hot idle in gear and 25-28 highway). With 40 weight pressure is closer to 35 highway and 10 at idle but it's always noisier (valvetrain). I can't decide if I want a mouse quiet engine or better oil pressure.
Any thoughts?
I've always ran 5w40, 10w40 or occasionally 15w50. It's had very low oil pressure since I put it in the car 12 years ago and 100k miles and it hasn't changed noticeably.
The oil pressure is almost low enough to scare me with 30 weight (4-6 psi hot idle in gear and 25-28 highway). With 40 weight pressure is closer to 35 highway and 10 at idle but it's always noisier (valvetrain). I can't decide if I want a mouse quiet engine or better oil pressure.
Any thoughts?