Chevy & GMC Vans

Howdy folks!

I had some questions about water pumps. I currently have a 6 year old cast iron water pump on my 97 Astro (I purchased it as a new pump not remanufactured) and I don't remember if the previous water pump that I removed was cast iron or aluminum. So I am wondering which water pumps GM installed at the factory on new Astros - iron or aluminum?

Also, what are your thoughts in general on the topic of iron vs aluminum water pumps?

I dont think AstroSafari's were shipped with anything but cast iron pumps.
I am also interested in aluminum pumps.
Please pass along your experiences & opinions...

Aluminum pumps are strictly hi-po aftermarket parts. A lot more expensive although it can save you a few pounds.