




What caused my water pump shaft to shear off?
I pulled out from my apartment complex onto a local highway and my RPMs got to around 3500 then bam! Some steam, but not a lot. Still had power as I revved the engine and it responded. But since the belt was gone, no power steering was a bear to maneuver the thing to the side of the road.
Once I figured out what it was, I waited for a break in traffic, started it up and drove the tenth of a mile back home and parked. My arms are now sore from wrestling that thing through a U-turn, a left across traffic to a driveway, then another left and backed up into a space.
Further inspection revealed the only casualties were the water pump, the mechanical and electrical cooling fans, the fan shroud, and my hood. Somehow no electrical, coolant hoses, or AC lines were hit. What a miracle!
Parts weren't available locally today, so it is a next weekend project. Ordered the same brand parts that O'Reilly offers from Amazon for ~2/3 the price, and they have the shroud that O'Reilly does not.
So why did this happen? I have a stack of maintenance records for it, but not available for me to look through right now, so I don't know the last time the pump was replaced. Could the fan blade have broken, caused an imbalance which let the blade hit the shroud, causing it to explode and simultaneously shear off the pump shaft with the mechanical fan?
Since I'm not fixing this until next weekend, I have time to investigate if anything else could have caused this. I would rather not have to replace all of these parts again if this were to repeat right away. The truck just turned over 240k miles on Friday, and I just replaced the battery and starter a month ago and had an oil change done 3 weeks ago. I've since driven 2k miles, so I doubt the shop is at fault. I am also absurdly grateful that this happened at home, not somewhere between Tallahassee and Pensacola towing a trailer as I was last weekend.