Technical Catastrophic water pump failure

Stepped on the gas yesterday and car went into passing gear. There was a loud bang and some metal came flying by. 1931 Ford with 350 Chevy. Zip’s water pump riser and FlowKooler aluminum water pump. It seems the pump disintegrated and sent the fan into the radiator and out the side of the hood. I have included some pictures. Destroyed my Walker radiator and my hood. About 4,000 trouble free miles on car including previous hard acceleration. Any thoughts?

 

Holy smokes!

 

Here's an interesting thread that talks about the plate that is riveted to the Flow Kooler Impellor coming loose. Could that have happened to your pump? Can you post photos of the impellor? Open and scroll down.
is the flowkooler water pump worth it? | Jeep Enthusiast Forums
Would it be possible to replace that heavy steel fan with something a little lighter?

 

Fuuuu*k

 

The casing couldn't handle the load from the rotating mass...

 

The fan broke first, it had been cracked for a while. Look at the telltale pattern on the end where the blade used to be. The pump housing could not handle the imbalance, and it broke from the off center weight spinning that fast.

 

You never see that with an electric fan

a bit of levity in an awful situation. Fan belt too tight? They shrink as they heat up. Maybe stressed that aluminum riser? Just guessing

 

Dang!

 

WOW! That fatigue crack sure tells the story. Thanks for posting.

 

^Good catch Jim! Lots of mass there and an imbalance would overstress that thin casing quite easily.

 

If one gets this, you know.

 

Score another one for Squirrel!

 

I agree with @squirrel comments about broken blade. I had an OT truck with sbc and the water pump a shaft and fan walked straight out of the pump while driving and ate the radiator. Fortunately it just cost a pump and radiator.

 

Yep, Jim's correct. That blade's been broken long enough to show rust in the cracked part. The last half inch has been holding it.

 

Squirrel is right, I had a fan blade let loose on my stock Model A and go through the hood, the rust where the blade let loose is a dead giveaway. Sorry it caused all the carnage when it failed, stress cracks are hard to see and almost impossible to find without removing the fan.

 

A quick search for "FlowKooler aluminum water pump"
shows a couple variations, one with more reinforcing ribs.

 

Had a similar experience years ago with a 273 in a '65 Dodge Dart. Not quite as dramatic as your results though. It started off as a very random, erratic, rumbling noise that came and went at various RPMs. It finally ended when the water pump shaft broke and sent the hub and fan blade into the radiator.

When I got things tore apart I inspected the two pieces of the pump shaft. Like the picture @squirrel posted above, about half of the break in the shaft showed clean metal and the other half was dark and rusty. The pump shaft had apparently been failing for some time.

 

Excess stresses, will ruin the bearings on a OEM water pump.
This pump looks pretty light.

 

Late to the party, but as soon as I saw the picture of the missing flan blade, I knew what caused the problem. Jim is correct.

Had that experience myself once. Another time I was checking the oil on my hot rod and saw a completely missing fan blade. I have no idea how it got out from under the hood without causing any damage! I did replace the water pump along with the fan, wasn't taking any chance after the 1st experience.

Every now and then I will grab and tug on all the fan blades when I check the oil. If any blade moves easier that any other, or any blade shows any kind of damage, the fan gets replaced.

 

Yup the fan blade leaving the show early caused the chain of events that happened after the unbalanced weight was introduced into the equation. That really sucks.

 

At least you weren't setting the timing and checking full advance when it decided to let go. I know it sucks but it can be fixed. Good luck!

 

Good thing that blade didn't slice through someone's neck!

.bjb

 

Scary stuff!

The pricing on the Johnsons Walker rads is pretty scary too! Hopefully you'll just need a recore. Fixing the hoodsides will be an interesting job, not insurmountable though.

Chris

 

I'd say that the consensus is correct, that was an already cracked fan coming apart. I'd say that isn't a new crack though.

There are a couple of states that require a steel band around fans on rods/vehicles with no hoods or open sided hoods in their RCWs.

 

That's a one in a gazillion failure....I like to use the lightweight fans for less centrifugal rotating mass...

 

Pm sent

 

The missing fan blade was the first thing I noticed in the carnage left behind. I hadn’t looked at the fan closely after the fact. I was more concerned with getting the car home. This was a new steel Derale fan from Summit Racing, maybe 2 years old. I’m glad no one was hurt and that it didn’t let go on my trip to Louisville this summer. I can always replace parts. I did not want an electric fan on my car. I guess stuff happens. Thanks for all the replies. That’s why I asked. The only thing hurt will be my wallet.

 

You might want to talk to Derale...let them know what happened...

 

I’m so sorry , that’s no fun . Parts can be replaced , be thankful you or family member wasn’t under the hood tinkering when the blade let go . I had a Bud had one leave on a 36 Chebbie Coupe . Tossed it through the hood and onto the second floor roof . We just finished a tune up and timing set .

All new parts are off shore , you never know what you’re getting or how well it will hold up . Don’t know how fast it was turning , could have been rather fast with pulley diameter calculations determined .

 

The main thing is nobody got hurt and like you said it’s just parts and your wallet is going to feel most of the pain. But that’s a part that I’ve never thought about checking. I admit I’m with Billy on this one because all I run are electric fans but with my factory flatheads those rascals are 75+ years old and I promise that they haven’t been inspected other than making sure that they were clean enough to paint. This winter I’m going to be doing some cleaning and maintenance on mine so I guarantee that I will be looking at the fans closely!