it could be related to a worn engine and using oil that is too thin. in a worn engine i always use the heaviest oil that the mfgr recommends for my driving conditions. your 5w30 might be too thin. in that engine i would think that i would be using 20w50. i think that is what i used back in my saab 99 days, and neither of mine had more than 120,000 miles.

tom w

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.