Sheared water pump

wonder if there are batch numbers to see if they were produced at same factory during the same period.

 

I'm sure it is trackable given the knowledge of the manfacturers tracking systems.

 

@Lucario Runner

Correct. Either similarly poor castings, which would be astronomical to have closeness, due to age of vehicle and new part.

Which leads to installation related or another part causing an issue.

Since the s/c belt doesn't use the waterpump pulley for tension, then something weird is really going on. Alignment, fan clutch, etc....

 

That is fucking impressive. First place I'd look at are the weep holes to look for areas of compromise. Second I'd look at the fan and fan clutch, couldve been imbalanced. Lastly I would bring the system back to spec and do a leak down test/pressure test. If two virgin pumps did that and they were Toyota/aisian pumps (at least one was per the pic) it would take a bit of pressure to break one more so than hoses but worth a look.

 

Based on almost 40 years in manufacturing, about zero. I'm still leaning towards too much belt tension.

 

I couldn't see belt tension being an issue with the way the water pump is driven on 4.0l trucks, it sits in the middle of the belt so tension should be about equal on both sides no matter how tight the belt is unless it's routed differently with a S/C.

 

It's not. This Sc belt is separate.

 

This impressive >

 

Holy shinto that must've taken a lot of force to break that off. And I'm surprised the belt held up through all of that. I'm no mechanic, so just giving thoughts. Seems like one of the pulleys in that system just creates a ton of belt tension and shear force on that water pump. I'd check all the pulleys and maybe even replace them all to be safe. I'd also check everything the pulleys are mounted to since a lot of force was likely placed on all those pulleys. It's just the water pump was the weakest link. Was there any wear on the inside of the belt? Like it was dragging on a frozen or semi -frozen pulley?

My other thought is that it could be related to the supercharger install (pulley) since that's the only thing that changed from your truck working to blowing two water pumps in a row.
Maybe instead of a frozen pulley, there's one that just create a lot of resistance, since it seems to take a month of use before it breaks the water pump.

Anyway, hope you (OP) figure it out and I'd like to know what happened.

 

I don’t know what caused it, but it might not be a bad idea to inspect the timing cover once’s it’s off.
I’d be looking for stress fractures or cracks. I’m sure someone out there has the knowledge to look at the broken area of the pump under a scope and tell you how long it took to fail.
Was the pump stressed over time? Or a was it instantaneous failure? (My guess is no)
But those guys that have that knowledge, probably aren’t here on TacomaWorld worrying about a water pump.

I think there is more to it than belt tension. If that were it, I’d expect to see other rotating assembly fallers on the same belt. Such as the alternator, power steering, idlers, ect…

 

This is all anecdotal, so take it w/ a grain of salt, but as an engineer but I'd say that looks like a brittle failure, given the sharp edges along the fracture lines and lack of metal tearing or signs of significant yield prior to plastic rupture. The metal itself looks granular, but it's hard to really say without seeing the part up close. I'm assuming it's an aluminum part, so that probably explains some of what I'm seeing here.

Another thing I see is the shear plane follows a line that makes it look like this might have been a torsional shearing failure. Is there a possibility for something to get locked up between the pump & the fan motor? The idea here is the fan would be blocked from rotation and instead transfer that torque back to the pump housing, causing the shearing you see in the pic. It looks like the pump housing isn't bolted up correctly either, just looking at the bolts in the upper left and the lower right of the picture.

My gut says it was either a chinesium or counterfit part with poor QA/QC. Maybe OP returned the failed part back to the vendor and vendor unknowingly sent back another counterfit part from the same batch. I'd be interested to see what you guys thing about the torsion transfer from the fan motor though...

 

Give that man a beer...

 

Ho Lee Krap! that is most impressive and depressing at the same time. Did the first one land facing the same direction when it failed?

I don't have the SC, so I don't know the serpentine belt routing, but I'm wondering what would happen if the SC sucked the tensioner to max and wanted more. If that makes sense...

Do they offer a different tensioner for the SC?

I dunno. just throwing it out there...

Good luck in figuring it out

 

What fan motor?

The fan and water pump is turned by the serpentine belt that is driven by the crankshaft pulley.

Engine | Water Pump | Fan Clutch | Fan Blades