The Dietzl Mod

leerupert89

New member
Joined
Feb 9, 2022
Location
Maryland
TDI
2015 Jetta TDI
I know this is an old thread but I am surprised no one mentioned running the return back to the inlet on the filter head and putting a check valve on one of the outlets back to the fuel tank. So it would help with cold climates and keep positive pressure on the filter head. Also fuel is filtered to the engine and to the tank.
 

timsch

Veteran Member
Joined
Nov 12, 2009
Location
Brookside Village, Texas
TDI
2003 Mk4 Jetta (blue), 2003 Mk4 Jetta (black), 2011 Mk6 Jetta, all manuals
I just did this and had a couple of issues that I thought I'd contribute to hopefully prevent some headaches for future adapters.

1st: I used 1/2" NTP to 5/16" barb fittings to connect the fuel line to the filter head. I connected the stock fuel lines to the barbs, only to have to pull them back off because I forgot to add some padding down below for the filter to sit on. Problem was the lines didn't want to come off AT ALL. I checked my other fittings and noted that the barbs had very sharp edges and they were biting into the rubber like a pitbull on a mailman. It was all I could do to get the things off with a pick stuck inside the hose and worked around. I can't imagine how bad it'd have been had they been clamped on for a good amount of time.

I pulled the fittings back off the head, chucked them up in my lathe and turned them while holding a file on the points to round them off. Still plenty of profile for the rubber to grip onto, but at least now I have a fighting chance to get them off next time. The lathe is a luxury, but a hand drill could be used to turn them also with some adapters attached.

2nd: The filters have a larger diameter than stock, so the bracket had to be chopped and stretched. Understood. After doing that, it appeared that the side of the filter could have rubbed against the edge of the bracket that attaches to (IIRC) the engine mount as well as the power steering fluid reservoir. I pulled that bracket out and ground off enough of the side to give clearance. I was afraid that the vibration of the filter against the bracket could have worn a hole in the filter.

I'm heading out now to see if I can fit a hose clamp around what remains of the bracket. I'd like it to hold the filter tighter.
 
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