We have a 2007 C70 with 95,000 miles Last shop I took it to put 5w 20 oil despite my asking for 5w 40. They didn't carry 5w 40 in a Dino oil and screwed me. Won't go back there. I need to change it now and am having a problem finding Dino 5w 40. of any make. Just synthetic. What should I do? manual recommends Castrol 0w 40 or 5w 40 for my area.

 

My two cents would be to step up and run a 5w40 synthetic. I run synthetic all all my cars including a '00 S40.

As a primer, the numbers refer to the viscosity at a temperature range. 0wxx is more viscous than 10wxx at sub 0F temps and xxw40 thins less at temps over 85F than xxw30. So going into summer, a 5w40 should be fine. I'd consider a 0W40 if you were going into winter and live up north. The difference between synthetic and dino is the level of refinement and synthetic breaks down less due to heat over time, so synthetic is totally backwards compatible to older cars. Volvo often recommends using synthetic over dino where cars are subject to more extremes ie towing, mountain driving, high temp ranges. Also don't read too much into Castrol vs any other brand name oil. The spec calls for GF-3, API SL, and ACEA A1/B1 standards which all the name brand oils meet. Key thing is to just keep changing the oil twice a year or at the maintenance intervals which ever comes first.

 

Thanks. I went with a Mobil 1 0w 40 synthetic. Got to be better than that 5w20 the last place put in

 

that'll do ya. The 0W may be overkill depending where you live but won't hurt. I live in CT and we see -10F from time to time and 5W40 works fine.