Hi Ray,
I take it that you had the change done at Campbell Ford? I would call them and ask what they were doing putting the wrong spec. oil in your car. They'll make it right.
As far as the weight goes, I tried looking it up on the web, and the experts all say the same thing: follow the maunfacturer's specs. The 30 is the viscosity when hot, the 5 is the thickness when cold, unless I am wrong (a distinct possibility. That's why some comapanies sell 0W-30 for winter use: it's thinner and coats the engine more quickly. They also say not to use an oil with these numbers 30 apart, say a 10W-40.
98 Silver Frost SVT
97 BMW 540I Sport, six speed
"Blue is for sky, black is for soil, and white is for simplicity, purity and hope for the future"
"A coveted car should never stunt your life, but should make it more rich and interesting."
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