1. The cartridge filter works exactly the same as a spin-on filter. Only diff is you/we change just the element instead of the whole assembly.
2. The filter won't "pass" enuf oil w/o getting damaged to allow 100% oil flow all the time. Esp during cold starts and cold running when the oil is thick and doesn't flow very well.
As of late I've had several of my customers (I'm a Porsche tech, do all Euro cars to stay alive these days) take their "cartridge filter" Euro cars to the "quicky oil change" places (pick one, I've seen this from all of them, there's a sticker in the window. I know who
[email protected]#$%$d up your car) to save a few bucks. Now, what do you think the chances are that Spiffy Lube has the correct cartridge filter and is willing to follow the "process" (very similar to the '10 and '11 FJ system) to change the filter on an 06 2.0 Turbo VW Jetta? I'm going with Zip and Nada since the last few cartridge filters I've pulled out of Euro cars (with quicky lube style stickers) have been collapsed/sucked flat from being plugged.
Thinking about it, this is why there is a "bypass system". The motor still got lubed with motor oil it just didn't get filtered......
YMMV RON