Originally Posted by gtk3
Check gages warning light and the temp guage that went down to 100 while it was on
Might be related, might not. When the water pump was going out on my 07 Trailblazer it would cause one of the warning lights on the dash to come on. Been about 3 years back so I don't remember exactly which one unfortunately.
With a lot of research I tracked down the that the wobble in the failing water pump shaft was actually causing the system to detect a fault in the fan clutch. After a lot of head scratching figuring out how to get the water pump off without disassembling the entire front end and replacing it, the warning light quit coming on even though I put the old fan clutch back on.
While the bad water pump was still on, my coolant gage would fluctutae a lot. What I think was happening is that it would usually circulate just fine but occasionally quit circulating, my temp gage would climb up to the overheat zone as the coolant got hotter and hotter, then it would suddenly drop to about half of normal as the coolant started circulating again allowing the now "over cooled" coolant that had been trapped in the radiator to flow.
Long story short. A failing water pump can cause a fault light for the fan clutch and cause temp gage fluctuations between normal, hot, cool.