[T5 TDI]

You can prime the filter (or add injector cleaner) with a miniature funnel if you want to but with your four pipe version you can simply cycle the ign 10 or 12 times with all pipes connected to fill the fuel filter. Or use this method. http://www.brick-yard.co.uk/forum/how-to-change-the-fuel-filter_topic40352.html

 

[T5 TDI]

You're right Dan. I read the post as a man who had bought a new fuel filter and just wanted to know if it was necessary to prime it. So I answered on that basis.

To answer chemicalali's post properly- You can run the low pressure pump via VCDS as Martin says. But since most folks don't have registered VCDS, you can take just take the feed pipe off the fuel filter (see my link above) and just watch the flow as you cycle the ignition. There probably is an official VW flow rate in litres per minute for the low pressure fuel pump but really you just want to see what I would describe as a good fat consistent flow.

For safety, ever loosen any connection after the fuel filter on a PD or common rail (CR) engine.