I have an interesting condition with my 18 year old md 22l engine. About 5 years ago I changed the cam belt and carefully retimed the engine using the 3x 6.5mm dowels to lock the crank cam and pump. Belt was then tensioned to the correct tension with a gauge. The engine ran fine apart from a very slight decrease in idle speed[ 50 revs maybe]. At the next oil change ,and every one since the oil is as clean as a petrol engine oil change. The engine uses a bit of oil but then it did from new[its a Volvo after all]. Any ideas why this 18year old has suddenly cleaned up its act ? We have just got home after 2 months away and the motor didn't miss a beat . Geoff
