Yes, 20 miles is a indicator of something very wrong. FWIW, the shops around here wont even offer a warranty unless you use a new Cooler or have your current one cleaned out with a special pulse/pressure type flush system.

Jasper being at the top, I dont think they will even allow you to use your existing cooler for fear of scapnel. You need thier $250 cooler if I read thier warranty right.