Hi there,
This isn't anything super-important, but I was just curious-
I have a '78 Buick Regal with a 3.8 V6. I had the oil changed back in
January to (non-synthetic) Mobil 5W-30 because it starts better with
the 5W-30.  Thanks to walking a lot and using public transportation, I
have only driven the old beast 900 miles since then.  The old
Chilton's book says only to use it up to 80 F in my car, but someone
told me that was probably just because late-70s oil was not as good
technologically. Anyway, do I have to change my oil now, or should I
let it go the full 3000-5000 miles?