Damage would occur to the engine if the oil pressure is too low. If it is not, then follow the recommendations in your owner's manual. There is a chart in there that shows what viscocity of oil to use according to what the ambient air temperatures are. What kind of climate is the car exposed to?

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Ali Al-Chalabi

2001 CLK55
1999 Dodge Ram 2500 Cummins Diesel
2002 Harley-Davidson Fatboy
Merlin Extralight w/ Campy Record