Mobil or Valvoline products will do just fine. Use a high quality filter such as Mann or Wix. If the car is a turbo, go no longer than 3,000 between changes!!! Just keep the oil clean and drive the car, dont baby it and dont flog the crap out of it either. As far as diesel oils, I wouldnt do that. Youre engine is too old as diesel formulated oils have a lot of cleaning ability. Youre engine is just getting broken in so best not to do anything to drastic now.

Brett

Rotella 15W40 is FINE in the engine and probably will go easily 5000 mile oil changes. I use Rotella and Rimula at times when not using Rotella T Synthetic or Mobil 1.

Thinking about switching to Chevron Delo 15W40 with Isosyn because it will apparently flow OK at low temps (above 0 Fahrenheit ?) despite being a 15W40 weight.

Volvo RECOMMENDS 15W40 weight oils for high oil consumption/high temperature use. My B280F has 267,000 miles, my B230FT has 250,000 miles.

Stay away from 10W40 oils unless they are synthetics and go straight to 15W40. Volvo said the vast vast vast majority of 10W40 oils are a "No, No" for its engines. 10W30 are OK for milder climates.

I purchased my Volvo 850 a year ago. I have used Rotella in my car. I usually rotate between Rotella and Amsoil every 3K miles. Anybody who says Rotella is only for diesels has no clue what they're talking about. I have personally asked Shell if its bad to use Rotella in gasoline engines and they say no its not. In fact, if you look at the characteristics of Rotella oil and compare it to regular motor oil it isn't really that much different. The big difference is in soot control. Rotella is excellent in keeping soot from building up in engines. Think about it. A diesel obviously creates more soot than a gasoline car. So why would Rotella be bad for a gasoline motor? Check out the link below. I used Rotella Synthetic with Mann oil filters and its great. It really helps keep the inside of your car clean. Ask any trucker who's opened up their diesel engine after using Rotella. They will all tell you how remarkably clean the inside of the diesel engine is when they break it open after a million miles. If you still aren't convinced then use Amsoil. It is superior to Mobil 1. And don't believe what they tell you about extended drain intervals. Oil changes every 3K miles is the only way to go. I always laugh at people who say its a waste of money and I should do oil changes every 5K miles. I had a 1986 Audi 4000 quattro that had 300K miles and it was still going strong but I donated it when it just got too old. I did 3K mile oil changes on that car and the engine never had any compression problems.

http://www.shell-lubricants.com/products/pdf/RotellaTSynthetic.pdf

I run rotella in my diesel truck but I wouldn't run it in my 850s. While I'm no oil expert I've always heard oil formulated for diesel shouldn't go in a gas engine and vice versa.

I run 10w-30 year round in upstate NY and have 287,000 miles on my '93 and 189,000 on my '94. Tried Mobil 1 and synthetic blends too. My conclusion - if you change the oil when it needs it with a name brand oil you can't go wrong.

If you are having oil leaks and thinking the thicker diesel oil would help check your flame trap. When clogged they make oil leak at whatever weak spot you have.