Originally Posted By: r34dy2fly
The car calls for a 5W-30 with 10W-30 for higher temperature areas. I'm pretty sure I fall within that spec seeing as I live in Louisiana. I recently did a oil change using the 5W-40 Pennzoil Ultra Euro I had left. I figured I'd be okay with the thicker oil seeing as I live in a high temperature area but as a precaution I bought a bottle of 5W-20 to mix in with the 5 quarts of 5W-40.
Should be good right? Does Volvo have a specific reason they want the 30 weight? Car has about 99,000 miles.
Volvo also specifies a 5W40 if used in Europe...and in the fine print, specifies it in the US for severe service...so a 0W40 would be a great choice, as would the GC 0W30.
If you search the UOAs, you'll find my 2 Volvos, one with M1 0W40 (great UOA) and one with PU 5W40 (also great UOA). So, my advice is to run an A3/B3 quality oil and change it on the Volvo recommended interval of 7,500. In my cars, they could have gone to 9 or slightly more, based on TBN, but I can remember 7,500...that's when the light comes on...
In addition to the UOA, I had a chance to peek inside the crankcase at 143,000 miles when I changed the oil cooler o-rings...clean as a whistle...
Volvos are known for plugging the PCV system (flame trap) with sludge...but my belief is that poor maintenance, i.e. using wrong spec oil, is largely to blame. Take a look at this TBN on Volvos, it lists how to clean a sludged engine...then recommends an A3/B3 vs. the A1/B1 recommended in the manual...
http://www.volvoxc.com/resources/how-to/pdf/01-23-09/TNN,%20Lubrication%20System%20Contamination%20Cleaning.pdf
If you're using PU 5W40, that's a great choice...based on my UOA and experience...