Hi
I had to change my pulley and its a normal thread. It will be hard to remove, search the forum for more info.
Regards
I recently changed the crankshaft pulley on my Vauxhall. The bolt is a stretch bolt and unbelievably tight, even with a 4' tube on the socket I couldn't budge it. Fortunately I was able to drive it 50 yards to a guy with a decent impact gun, he had the old one off and the new one on in 10 mins, I tried for 2 hours!
What you need is one of these, Sealey Tools Impact Bar Wrench 550mm 1/2”Sq Drive VS786, its the only thing to touch it and you won't need to remove the radiator.
There are lots of videos on utube showing how to get one off, but some methods are downright dangerous, like using the starter motor.
I even tried the starter motor trick, didn't work but it certainly made me sweat!
One of the problems I had was jamming the engine, with the impact gun it didn't need it.