Missing water pump blades
 

My 2002 Boxster 3.2 that I got for my youngest son to drive on the track had a water pump fail. It never ran hot, just started making a rumbling sound after start-up, then after about 10miles near the destination the low coolant light began to flash. Returning home after topping off with coolant, temperature never went above whats is normal. The water pump is a little over 2 years old and less than 20k miles.Has the OEM black plastic impeller that is missing the tips off the blades. I spent a long time back flushing the engine and trying to catch the missing pieces, no pieces were recovered. I can only hope that the pieces made it through the engine and found a non-critical resting place in the heater core or radiators, or even a non-critical place in the coolant passage. The pieces should be relatively small compared to the passages in the cylinder and head. I fabricated some screens to catch any pieces if they return to the engine, or if another water pump happens to fail at some point down the road in the future. I would recomend this mod to anyone rebuilding thier motor or having the pump off for any reason. The metal screen is .250 welded squares with .025 wire diameter, the fiberglass screen is .125 squares with .008 thick strands ( gutter guard screen). Has been on for over a week, temps are as they should be..
https://cimg2.ibsrv.net/gimg/rennlis...a4545e56eb.jpg
Missing blades
https://cimg1.ibsrv.net/gimg/rennlis...1e9cd42c3d.jpg
metal screen with fine fiberglass top screen
https://cimg1.ibsrv.net/gimg/rennlis...ef18e7413f.jpg
fine mesh "gutter guard"
https://cimg9.ibsrv.net/gimg/rennlis...463693f26c.jpg
test fitted on spare short block I've had sitting on a stand in my basement for years, hopefully I never need it..
https://cimg9.ibsrv.net/gimg/rennlis...ed0a72d78c.jpg
spare short block showing coolant passages
https://cimg9.ibsrv.net/gimg/rennlis...c513afe2f5.jpg
spare head showing coolant passages

For some reason a couple pictures didn't load, so they are below..
https://cimg1.ibsrv.net/gimg/rennlis...6649fb82a0.jpg
missing blades
https://cimg0.ibsrv.net/gimg/rennlis...8d629186ec.jpg
welded wire mesh with fine fiberglass mesh," gutter guard mesh"
https://cimg8.ibsrv.net/gimg/rennlis...beae108046.jpg
Boxster on track
https://cimg6.ibsrv.net/gimg/rennlis...203e371e21.jpg
My 99 996's going head to head( me and my oldest son)
https://cimg5.ibsrv.net/gimg/rennlis...a7ef1e55d5.jpg
I let him pass..lol
https://cimg0.ibsrv.net/gimg/rennlis...4203646838.jpg
after a week with new water pump with screens all temps fine

Definitely an interesting idea!
That said, is there any data that shows the size of the smallest coolant passages?

Yikes, when my water pump went it just dumped coolant out of the bottom and the tank made a gurgling noise. Was two weeks after I bought it!

I don't know of any data anywhere, but from what I can see without slicing a head in sections with a water jet, the smallest passage appears to be the slots in the block deck to the cylinders, you can see them in the pictures. They range from .165 to .225, so anything that can block them will be caught by the fine mesh (.125)..

I wonder if there is a easy/good source for stainless mesh (like in reusable oil filter cartridge filters) to do this with? Perhaps a kit could be made for field testing these awesome debris filters?! I'll beta test!

So what is the theory on how the blades were taken out?

How is the screen held in place? Spring tension? I take it the finer mesh screen is 'tabbed' to the coarser mesh?

I too would be concerned with the fiber/mesh softening and getting clogged up in there. Seems like a great idea though, thanks for sharing.

Yea, that's exactly what I was looking for, but couldn't find a source.

Try here: https://www.mcmaster.com/mesh

The sealed bearings in the water pump( think IMSB) started to fail causing a wobble of the shaft and impeller, the impeller contacted the case breaking the tips. V. Yes the welded mesh is held in with spring tension and tabs, the fiber mesh is laced/ tabed at the edges..

Yea I thought about that, but I think the fiberglass mesh will be fine in that environment. But this is a test and I will know in years to come.For me I think risk is worth not having water pump debris circulating.

The problem I found in searching this source and others , is that the fine mesh stainless steel or similar is a woven strand, NOT WELDED.The woven strand wire cloth tend to unravel at the edges, that's why I chose the smallest welded wire cloth I could find which is .250, and used the fiberglass cloth as the fine mesh (.125)

They do get lodged in the head. I have physical an photographic proof. Had a piece fall out when I had my heads off. Look up my "Dragged me home one of these" thread and you will see the picture of the piece that fell out of the head when I was lapping the valves. The piece was from a previous pump that the owner replaced some time before I bought the car with bent valves.

Yes, this was my main concern, and the reason I designed and install the catch screens. I wish I had thought about it and put them in YEARS AGO !!