I have a '99 Jag (my daily commuter) that decided, after its 18th birthday, to burn a quart every two and half weeks or so.no driveway spots or exhaust smoke, so at $4.58 a quart conveniently delivered, this case of Havoline last me 6 months and sure beats the cost of a ring job or valve job.
Here is So Fla, going up to 40w is logical.