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Sun Oct 19, 2014 5:52 pm

Howdy.

I'm slowly tearing down the wbx engine in my '86.

This is my 1st time taking off a water pump. (It came off much easier I feared. Unlike the exhaust, all the hardware came apart w/o any broken bolts.)

I'm planning on replacing the pump; seems like cheap insurance while I have everything apart.

Question -

Are the dings / pits in the pump mount area normal or something to worry about? They just seemed kind of odd to me.

Wider shot:

And... an inside shot of the water pump for good measure:

FYI, all of the hard pipes look spotless (inside) and reusable. Plan to blast & paint the exterior of my hard pipes & reinstall along w/ new water pump & hoses.

Sun Oct 19, 2014 6:49 pm

looks like someone have been in there with a punch for some reason, can't think why it'd be necessary

Sun Oct 19, 2014 9:17 pm

I recently posted on the Vanagon list about wear at case next to pump impeller. It was suggested that an epoxy could be used to fill that wear and level out the surface. It was also suggested to drill small holes at that wear point so the epoxy had something to grab to.

Maybe PO attempted similar? In your images, is that filler I see at the same wear spot?

Neil.

Mon Oct 20, 2014 5:13 am

Vanagon Nut wrote: I recently posted on the Vanagon list about wear at case next to pump impeller. It was suggested that an epoxy could be used to fill that wear and level out the surface. It was also suggested to drill small holes at that wear point so the epoxy had something to grab to.

Maybe PO attempted similar? In your images, is that filler I see at the same wear spot?

Neil.

Neil - thanks for the "unmolested" pic.

The holes make sense as a gripping surface for epoxy. The stuff "built up" in there now is brittle - I can crack bits off it w/ fingernail. Also a bit nervous that the grip-holes are top and bottom, but only top filler remains. you can see how the filler is "pressed" into the gripping holes.

I know neither PO did any wrenching - everything was done at shops. This engine was one of the "last" NOS engines, put in about 9 years ago. By docs & odometer, it only has ~30k miles on it, and I think the water pump was new at time of engine replacement. I've got to dig through the paperwork to verify.

This makes me think the VW dealer (no longer in business and 500+ miles away) who completed the engine swap also did the epoxy on the "new" block? Or maybe someone in the supply chain lied & that last PO got a rebuilt block w/ new bits on top (receipt shows full NOS engine crated from Germany) - wear an all?

Does anyone happen to have an old pic of a low-milage engine? I'm curious to see what it looked like "new" vs. what Vanagon Nut and I have...

Thanks,
Joe

Mon Oct 20, 2014 6:21 am

The "punch marks" you see could actually be signs of captivation in the water pump. Probably due to running the antifreeze too long, wrong antifreeze or too much H2O in the coolant.

Captivation causes small bubbles which explode with great force..knocking chunks off the engine case or water pump. Depleted antifreeze will cause this to happen.

See the pictures of a 2.1 water pump housing in an engine case. This engine ran too long without a coolant change and the wrong (old fashioned green) coolant too.

Mon Oct 20, 2014 6:51 am

AtlasShrugged wrote: The "punch marks" you see are actually signs of captivation in the water pump. Probably due to running the antifreeze too long, wrong antifreeze or too much H2O in the coolant.

Captivation causes small bubbles which explode with great force..knocking chunks off the engine case or water pump. Depleted antifreeze will cause this to happen.

See the pictures of a 2.1 water pump housing in an engine case. This engine ran too long without a coolant change and the wrong (old fashioned green) coolant too.

Atlas -

Good info on the cavitation damage - clearly visible in the pics you included.

Close up of my holes:

Huh - they look like they were drilled in. It sure looks like cavitation damage all around the area (darker marks & spot abrasion, makes sense that that would be caused by the method you described) - but the holes look too regular / drilled to my eyes. A bit scary if that is the cause!

Thanks as well for the image showing the "flush" facing where the impeller meets the engine case. Looking at the design of the water pump, any idea of the effect from the wear (that both Vanagon Nut & I have) on coolant flow / engine cooling?

Thanks,
Joe

Mon Oct 20, 2014 8:51 am

I'm going to theorize that the your engine case was a VW rebuild and VW repaired the captivation damage with an epoxy. It looks like there are many more pitted areas with some epoxy still stuck there..the dark round spots. The very round pits (the drill like holes) are normal as the bubbles in the coolant explode with great force and can look man-made and very round like a crater.

Most of the epoxy has come off the engine case. Interesting that the epoxy that is still there has some captivation "pits" too.

If I were to try and repair I would remove the big chunk of epoxy the lightly sand the effected area. Clean up the area with acetone..the aluminium surface oxide layer must be removed completely by sanding and very clean. Then use some JB Weld and an old plastic credit card as a tool to smooth and blend the JB Weld. Try and replicate the original surface. Don't try and pull out the old epoxy from the smaller pits..Let the JB Weld fill in the exposed pits.

With Vanagon Nut's engine case where the water pump impeller has ground a notch..I would do the same thing. Clean it, sand it lightly to remove the surface oxide layer, wash it with acetone.

A clean oil free and fresh aluminium surface is needed for the JB Weld to stick to. I would not try and drill or punch marks in the engine case..it wont matter. JB Weld is very strong.

Alow the JB Weld to cure overnight and check your work. Test fit the water pump to be sure there are no "high spots" in your repair. If so you can sand the JB Weld to remove them.

The other option would be to have the engine case electrically welded and machined flat again.

Unrepaired the water pump efficiency to move coolant is reduced.

Mon Oct 20, 2014 9:48 am

I am a big fan of JB weld. That said, I would recommend this product for building up your waterpump area. http://www.goodson.com/Port-Reshaping-Kit/

It is used for shaping intake ports, but should work better than JB weld for your application. The only problem I have with JB weld is they are not really clear about what it can take. You sort of take your chances, but again, have always had good results using JB Weld. I have also had good experience with the Goodson product on our race heads.

Mon Oct 20, 2014 10:06 am

To me your engine shows signs of a water pump failure having occurred some time in the past. You can see how the shaft wore into the pump and I think that where the epoxy is was worn by the impeller. Don't have a better fix than to use more epoxy, though maybe a guy who is good with welding aluminium could build the area up and make it like new, don't really know much about the weldability of these things.

If you want to try epoxy again go through and drill a pile of deeper holes to create more grip surface.

Mon Oct 20, 2014 10:07 am

rsxsr wrote: I am a big fan of JB weld. That said, I would recommend this product for building up your waterpump area. http://www.goodson.com/Port-Reshaping-Kit/

It is used for shaping intake ports, but should work better than JB weld for your application. The only problem I have with JB weld is they are not really clear about what it can take. You sort of take your chances, but again, have always had good results using JB Weld. I have also had good experience with the Goodson product on our race heads.

rsxsr -

Thanks for pointing out the option. I'm interested. Product description says:

Superior formula adheres with heat, dries without shrinking. -

What is application process vs. the mix and go of JB weld? Have you rebuilt any "wet" ports, or just intake/exhaust? I suspect it would be fine w/ a prolonged coolant bath...

Mon Oct 20, 2014 10:46 am

That is interesting. Or maybe the epoxy sunk into a cavitation hole while setting up?

I took a chance on not building up that area on the case as I didn't want the stuff letting go and ending up in the "new" cooling system. This is my first time looking inside a WBX so have no relative POV, but the wear I saw doesn't seem as bad as unplannedbbq or atlasshrugged shows.

unplannedbbq: fwiw, I"m pretty sure that when the pump wears, it will move in/out and create the wear at case.

In my post to the vanagon list, someone suggested west systems might be suitable. I thought maybe this one?

http://www.westmarine.com/buy/west-system--g-flex-650-k-aluminum-boat-repair-kit--9223140

AtlasShrugged wrote:

.... Interesting that the epoxy that is still there has some captivation "pits" too.