Short and sweet, yet useful. Many of us have performed the most basic of maintenance procedures, an oil change, where we've had a cartridge insert filter instead your traditional spin on. In some of today's modern engines some of these filters are inserted down into an oil filter housing rather than fitted up into one from below the vehicle. Now I'm sure there's one question that has run across all of your minds at one point or another: "Which comes first? The chicken or the egg?" Meaning, do I drain the oil or do I remove and replace the oil filter first?
Believe it or not, on Volvo's 3.2L and their late T6 engines the order of events does make a difference.
When changing the oil on the inline 6 cylinder, it is very important to remove the oil filter first before draining the oil. The oil filter housing on these engines are equipped with a spring loaded valve which is closed shut by the pressure of the oil filter element. What that does is to maintain a level of oil in the filter housing during engine operation and to ensure a fast rise of oil pressure during start-ups. Removing the filter first allows the dirty oil that is trapped in the oil filter housing to drain back down into the oil pan. Now you know.
