Two questions: 1. What are people's experiences with Prestone Super Radiator Cleaner, it appears to dissolve scale and
2. What is the best way to flush the coolant system of an XJ8?


I am in the middle of replacing the brushes on the heater pump motor. I got a pair of Dremel carbon brushes at Ace Hardware/Sears. These were slightly too big but I filed them down to 4x4mm by rubbing them on a metal file.
At the moment I have a piece of hose spliced in to where the pump goes.
My first attempt to flush the heater was not successful, no flow! I don't think that I was using all the right hoses but I could not get water to flow into the upper hose exiting the heater control valve. I know this goes to the matrix.
I will try to flush the upper hose leaving the pump when I refit the heater pump. This is the other hose going to the heater.
Bottom line, I could have a blocked heater matrix. I did notice white scale in the pump connectors but little on the pump vanes.