Fits all VW engines, gas or diesel, w/11 mm head bolts. Fits all gas engines 75-92(except 16 valve, VR6, and 1.8T) and early 1.5 and 1.6 diesel engines 77-82.5. Bolt length from underside of head to end 4 3/16 inches.
All VW diesels with 12 mm head bolts 82.5-02 including 1.6, 1.9, and early and late TDI. These do not fit gas engines. Bolt length from underside of head to end 4 9/16 inches.
...BTW your Bieber avatar is awesome.-Malone
the best way to tell is to go down to the hardware store and see if it will thread into a 12x1.5 nut.
Wanna know something funny?12mm head bolt thread is, if I'm not mistaken, the same as your lug bolt thread is the same as the CIS injector thread.