Answers about my 17 mpg in my Burb.

[Project1970]

FWIW, we've ran synth in several vehicles since they were new and never had an oil-leakage problem with the sole exception of IIRC one of the intake seals on the '94 Z28, and that was a massive TSB in itself (along with the unbalanced driveshaft!). The '97 Suburban had 95,000 on the clock without a single oil problem (transmission, suspension and cooling were all a different story, though!), the '94 Z28 doesn't have any oil problems (though it requires 15w50 when running synth) after 85,000, and the '97 E320 (75,000mi) and '02 TrailBlazer (12,000mi) require it specifically!

Every one of those has run it since new, too...whenever I get the money for a new engine (sheesh, new bottom end and new A/C... ) I'll also be switching over to either 0w30 or 5w30 Mobil1...