I have noticed that you can now find aftermarket water pumps for the 4.0L engine that have aluminum impellers as opposed to the plastic ones. Has anyone tried this? Would I be best served by going with one, or just sticking another plastic one in there?

 

Alot of people use them, I had bad luck with the first one I installed and sent the other back because I wouldn't trust it. Maybe I got the only bad one ever made. All the retailers probably buy them from Terry's Jaguar, so I'd bet they have the lowest price.