I had one on a prior TDI. I was driving 45k+ per year at the time, TDI mandated full synthetic oil and meeting VW's 505.00 specification, and the lower engine cover / belly pan was an ordeal to remove and replace. At 5k intervals (roughly each 6 weeks) I was spending 2 hours on an oil and filter change, $25 for oil and $6 for a filter.
A bypass filter reduced that to 15 minutes, $0.80 for an element, and one quart each two intervals as make-up.
Now,.... I did spend a bunch on oil analysis each 10k miles, but I discovered that the by-pass allowed me to stretch full changes to over 60k miles. I ended oil sampling and testing at 60k because that was a timing belt change interval and I needed to get under the car for that anyway, so a drain and new spin-on filter were no added ordeal.
I have cut an access hole so the belly pan can stay on, have a new job and drive maybe 10k a year, and now months (not miles) dictate that I change my oil. No by-pass system on the car now.
|