Waterpump failure (what happens)

[billwill]

I've done the water pump a few times in my 39 years of owning this elan, so I thought I might describe what happens for the benefit of other owners.

Once I had to do it while camping on a scuba-diving holiday, now that WAS tricky.

When functioning properly the waterpump has a seal spinning on the shaft, to keep the water away from the bearing. The seal used to be a strengthened carbon disk, but I think modern ones are improved materials.

The steel strengthening disk of the seal is in contact with the coolant and rusts away, when the seal fails water gets into the small compartment next to the bearing. This compartment has a small drain-hole at the bottom (you can't see it easily until you take the pulley off). If you see water dripping from the waterpump under the pulley, you know your seal has gone and it is time for a replacement pump.

You can effect an emergency get-you-home treatment by blocking the drain hole with silicone sealer or somesuch. But if you do so the water will now be in contact with the back seal of the actual bearing. Modern bearings seem better than the originals, but eventually the water will get into the bearing and force the grease out and your bearing will wear away.. This creates the wobbly pulley syndrome, which tells you that your water pump has completely had it.

[billwill]

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I now have the modified chain case and modular waterpump pod from Vegantune UK (&), which can be taken out from the front, without needing to dismantle the front of the engine. I replaced the pump in this last December It had been in for about 10 years (around 50,000 miles). The seal had gone but the bearing was still OK as I had not blocked the drain hole.

Contrary to an earlier mention on this forum the Vegantune water pump module pod is not stainless steel, though it looks like it. It is an aluminium alloy such as Dural. This turned out to be lucky as the pump bits from Christopher Neil had a very slightly bigger outer end of the seal cup and I had to gently scrape (for hours) to make the recess in the pod a few thou bigger to get the seal fitted properly. All sealed up with silicone gasket goo of course.

Pulling the bits off and pressing and them back on is difficult!!! I have no idea how I managed to do that at a camp site so long ago. Nowadays I use my out-of-action lathe as a press to do that job.


(&) Vegantune's own engines don't have an internal water pump, so I had to twist their arms to persuade them to make one for me in 1997ish, I think they only had a prototype at that stage. It may have been originally designed by the original Vegantune (designers/builders of the Evante at Cradge Bank Peterborough) but they went bust & the business was bought up by the now Vegantune of London.


http//www.vegantune.com