Castrol 15W40 or Shell Rotella 15W40 in summer (Texas, VERY HOT, 40+ days of 100+ heat and no rain this year!) every 3500 + genuine Volvo oil filter $4.50ea/case of 12 from mail order Volvo dealer (almost out, probably $5.25ea now.)

Something from the seven sisters used as a loss leader at PepBoys during the winter @ 10W30 weight. Lately, a Valvoline oil that retails for $3.79/qt on sale with a $17.49 rebate on 5 quarts = FREE! (cost of sales tax and .39 stamp not included) or something else hopefully about .25 cents/qt after rebate, usually Exxon, Mobil, Texaco or Castrol.

Really, does it make a difference which brand?? If I had a digital camera, I'd take a picture of my engine with the valve cover taken off. Most Volvo engines, on the inside, look like someone spit tobacco juice on them. My enging looks like the inside of an aluminum soda can, nice and clean for an engine with 250K

Mine is a testimony to the virtues of changing the oil every 3500 miles.

Man, I really like this car!
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If it needs to be maintained, repaired or replaced on a 1990 240, I've probably done it. '90 240DL, 245K looking forward to 300K badge. >>You haven't really worked on a car until you draw blood<< :-}