Holden V8 water pumps - Mick's Tips 411

By: Mick McCrudden

holden v8 waterpump holden v8 waterpump

Mick delves into the mysteries of old Holden V8 waterpumps

This is a common thing on old Holden V8s, and you’ll come across it on Windsor Fords, where they’ve developed a leak just behind the timing cover. You’ll be losing a little water or you’ll notice staining on the cover.

When you take it off, you’ll often come across damage from coolant cavitation and electrolysis. It happens on the softer materials in components, such as aluminium timing covers, rather than cylinder heads or block. Generally the cavitation and the stray current will go for the weakest link.

Electrolysis causes what looks a little like rust – essentially rot – while the cavitation from the standard rotary vane pump is surprisingly corrosive and can literally wear through a casing wall.

Holden -v 8-waterpump -mick

The other issue you get over time is the hoses start to weep at the clamping point, which leads to a build-up of scale on the joining point. The old trick used to be to apply a little Vaseline to the area when you fitted new hoses, but the risk is they’ll slide off again under pressure. A much better solution is to use a non-hardening paste like aircraft sealant or Permatex number 3.

As for the cavitation and electrolysis, they’re something that’s inevitable given the design of the engine and we are talking a fair few miles and a lot of time before it becomes a real issue.

When you do decide to replace the cover and the water pump, don’t be stingy. Get in there and replace the timing chain and sprockets while you’re at it. The cost isn’t huge and your car will thank you for it. A worn set can throw your timing out by four or five degrees, so doing the job properly is well worth the investment.


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