Welcome to the forum. welcometomyturbodies
Well there are some known Known fixes and bulletins for the Passat. They list 01-05 and 05> do you know the engine code?
The later 2.0 GTD TDI had a problem with the sump plug.
All models, 1999→.
Problem
Oil leak from engine oil sump drain plug after replacing engine oil.
Cause
Engine oil sump drain hole or drain plug thread damaged.
Remedy
Drain engine oil.
Thoroughly clean threads on engine oil sump drain hole and drain plug.
Check engine oil sump drain hole and drain plug thread for damage.
Replace component(s) as necessary. Tighten engine oil sump drain plug. Tightening torque: 50 Nm.
You could try and re-helix coil the thread, the problem is as your said getting thread tapped square.
Well there are some known Known fixes and bulletins for the Passat. They list 01-05 and 05> do you know the engine code?
The later 2.0 GTD TDI had a problem with the sump plug.
All models, 1999→.
Problem
Oil leak from engine oil sump drain plug after replacing engine oil.
Cause
Engine oil sump drain hole or drain plug thread damaged.
Remedy
Drain engine oil.
Thoroughly clean threads on engine oil sump drain hole and drain plug.
Check engine oil sump drain hole and drain plug thread for damage.
Replace component(s) as necessary. Tighten engine oil sump drain plug. Tightening torque: 50 Nm.
You could try and re-helix coil the thread, the problem is as your said getting thread tapped square.