Water pump failure destroys radiator

[austinado16]

The water pump shaft sheered off, flush with the front of the pump, while driving on the freeway last night. This sent the radiator fan w/ clutch, pulley, and water pump hub, forward, into my brand new extra-long radiator.......carving a huge section out of the radiator. The spinning fan then collided w/ everything on the front of the engine, destroying the fan.

No idea why it happened. We'd been on the road for 100mi, and I was going around a slower moving car, as I headed for my exit ramp. Gave the throttle a little bump to get a downshift. The transmission shifted down, and then *BANG*.......battery warning light came on, headlights dimmed, and the power steering was gone.

Drove on down the ramp, and continued about 1/4mi to our destination, with the engine still running fine, but of course, no power steering, and the coolant temp gauge was creeping towards 200*F.

Parked and got out, and there was steam rolling from under the hood, coolant flowing across the pavement, and then I opened the hood to find the fan half-way out of the engine compartment, stopped only because it got tangled in the top hose.

Radiator, fan, fan shroud, water pump, and power steering pump pulley are all destroyed. it was dark, so there may be more damage. Going back with a buddy tomorrow morning to trailer it home. I'll update with photos after that.

 

[Fastereddie]

Damn... that sucks. Sorry

 

[VAL]

Wtf!

 

[Rusty Nail]

This is gonna make some kewl pics!

Excuse me, I need to tighten my fan bolts.

 

[smoothandlow84]

Ouch!! That sucks beyond comprehension.

 

[austinado16]

Here's how I've had the fan mounted, for about 2 or 3 years.......with that 1-1/4" fan spacer. Could that have caused the water pump shaft to sheer off at the front of the pump, because the weight of the fan & clutch is moved so much further out from the bearing in the end of the pump?

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[Rusty Nail]

I think I would look at the bolts first.

But why is it so far into the shroud?

 

[74 Shortbed]

Damn, that sucks the big one..

 

[74propu]

I feel your pain. the same thing happened to me back in the 80s the hub came off the water pump and the fan went threw the rad and wedged in the shroud.
I got lucky the water pump was only about a year d and I took it back to the parts store and the store put in a clam and the GM supplier contacted me about a week later . I sent them pics of all that got damaged and they replaced it all with new parts . pump , fan , clutch ,shroud and radiator. Good luck

 

[yevgenievich]

putting the fan blades further out from the hub will place extra load on the water pump. It would be less likely to happen if it was mounted in original position, but if pump was defective then nothing would have helped.

 

[CorvairGeek]

Definitely added load with the spacer, but not unheard of either with all the junk on the market.

Hub fell off a 22 month old pump with 20K miles (I still had the box). Obviously not much of a press fit, you could see a bonding compound on the shaft. 'No load' compared to having a mechanical fan.

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The hub landed on the sub frame and the belt dropped so fast it wasn't even damaged by the HB still spinning on the engine.

I am so thankful my 16 year old daughter was able to get off the road and even get the car into a parking space. She said she heard a terrible noise, the battery light came on, and the car was really hard to steer (good thing she is an athlete trying to man-handle an unassisted GM front drive).

 

[fussfeld]

i thought bosch was the highest quality..........

 

[austinado16]

Answers to some of your questions/comments:
The reason the fan is spaced forward is that I've installed the much longer radiator that was only used in the 2WD 454 models. The fan shroud that fits that radiator is not very deep, because the 454 engine sticks forward toward the radiator more. It's a standard fan spacer that's available from NAPA or other sources (not that that means anything, of course). All bolts and nuts are still tight.....so there was no failure there. It's simply a sheered off water pump shaft.

As for the condition of the pump. It is very likely to be an original GM pump, and it could be the original pump, now with 298k on it. I purchased the truck at 224k, in 2004, and I can't remember if the pump looked brand new at that time, or not. I kinda doubt a pump could live 300k, so it may not be original, but the original owners (who I got the truck from) always had it serviced at the local GMC dealer, so even if it's not the original pump, it's an OE pump that predates all the crap made in China (like the Bosch pump photographed above). And that's why I've never touched it......because I knew it was excellent OE GM quality, and I knew if I put something new on it, no matter who I purchased from, I'd be getting China crap that would fail in 18 months or sooner.

My buddy down the street helped me trailer it home this morning.

I was able to straighten out the fan blades with a little finesse from a BFH and an anvil. Hammer-to-fit-paint-to-match.

Photos of the carnage for your viewing pleasure:

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[Rusty Nail]

Wicked.

 

[austinado16]

From a tech article I found online about water pump failures:

Probably running a spacer with a heavy, stock steel fan and heavy clutch is no bueno.

Clean break indicates an “instantaneous” fracture caused by sudden overload or imbalance.
A break usually occurs through the front bearing race portion of the shaft. This particular break can be noted by a clean fracture, rather than blue heat discoloration, which can appear in this same type of failure.
Cause of Failure: Bearing Overload
This bearing failed as the result of a sudden overload caused by vibration or imbalance. The lack of heat-related discoloration indicates that this was sudden rather than gradual, and was probably compounded by rapid engine acceleration. Blue discoloration of the shaft would indicate that there was excessive heat build-up for some period prior to shaft breakage. This heat build-up can be caused by the tremendous centrifugal forces created by imbalance. This overloads the bearing generating a great deal of heat. This load is amplified through rapid acceleration and high RPM operation.
Remedy: Carefully check alignment of all pulleys. Also check the pulleys for straightness or fatigue. Install belts using a belt tension gauge according to manufacturer’s recommendations. Carefully inspect fan/fan clutch assembly for a bent or damaged fan, a worn spacer, or a worn or damaged fan clutch. Be sure to evenly tighten the mounting bolts to manufacturer’s specifications.