I haven't changed mine yet. I had rotary cuff surgery and that put a stop to anything for a while. I did buy the tool through Napa and talked to our tool rep that has changed them. He said they popped it with an air chisel but you have to take care not to bust the housing. I also talked to a guy that had to cut the old water pump apart because it was so corroded on the aluminum housing it screws into. They said be patient and careful. The rate my shoulder is healing, I'll be able to fix this in......November 05.