Last fall I purchased a 1999 Volvo S70 with 143K miles. It's AWD, 2.5 liter straight-5 with a low pressure turbo. The owners manual specifies engine oil should "meet API specification SG, SG/CD, SH or Engergy Conserving (EC) II". Recommended weights are 5W/30 for temps up to 86 deg F, 5W/40 for...