My 2002 Silverado - DM (189K) started to spit out coolant as soon as I switched it off. People came after me and said "Your truck is leaking"
Observing the temp gauge jerking up to above 100C then down to 75 and back up again I decided to change the two Thermostats.
A piece of cake! (Well done DURAMAX Engineers!) A 2 hour job,drain, refit, refill, run up to temp and blead air.
RUNS LIKE NEW / NO LEAK's / NIECLY CONTROLS TEMP AROUND 90C
COST $62.00CAN
Great,ehhhhhhhhh