In Reply to: Use 15w50 mobile1 for summer? -e posted by //E36er on June 12, 2000 at 14:17:56:
Car never even whimpered.
BUT, I did get some valve clatter at cold start up.
FWIW, I'd go with 5/30 Mobil 1. I switched back to when I returned from the road trip. Much easier cold start-ups.
And since it's sythetic, it's visc breakdown point is already WAY up there 5/30 or 5/50.