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I had thought about the electric pumps but for the cost and expected life expectancy I'd rather stick with the conventional pump.

Maybe for an all out drag/competition car it would be good so you could keep it running after shut down to help cool the engine.

My success or otherwise with water pumps has had a lot to do with the type of coolant used.

I have never used an OAT coolant in my own cars, but some mates who did (got it for free) were replacing water pumps every couple of years. Use a glycol based coolant and the pumps will last. Or use HOAT coolant with a new pump right from the start, and it too will last. Switch to HOAT after glycol and it’s a mixed bag as to whether the pump will leak or not. Straight OAT is useless.

But clearly there must be some quality issues with these cheaper GMB pumps.

That's interesting because Holden used the DEX-COOL coolant for the V6 engine, Isn't DEX-COOL AOT type coolant?

I ran Dex cool in my old VN for years, never had any major issues. In all my other cars it's either been glycol based or just H²0.....

There have been class action lawsuits in the US against GM for problems caused by DEX-COOL in engines.

I just use a quality ethyl glycol. Found penrite to be good, nulon seems ok in my brother's 5L. I had used cheaper brands of glycol with bad results. Coolant would always go brown and rusty looking after 6 months and corrosion on the alloy parts. Penrite and nulon remain looking clean.

The OAT red coolants I have never touched. I dealt with turdota and that OAT is nasty shit, they add silca to it, so when it get everywhere you get this white cement like powders on everything you can't wash off unless you scub with a brush. Thats the silica, basically fine sand. Seems like that would be asking for trouble.

http://www.tectaloy.com.au/product/deta ... -boil--red

thats what i had always been using, guessing its OAT or organic then but it also says it has Ethylene Glycol. It does say it's Silicate, phosphate & amine free.

What is everyone else using?

Tectaloy for 15 years

Well the coolant I used doesn't exist anymore, but it was superseded by a newer compatible type. Just has a bit longer life. 350k rated instead of the 250k mine is.

http://www.penriteoil.com.au/assets/pis ... 20CONC.pdf

There is a newer one that supposedly lasts 500k lol love the marketing.

If the Tectaloy is OAT with glycol, then its HOAT = Hybrid Organic Acid Tech. In theory, should be the best of both worlds. OAT depending on the type, should have superior corrosion protection, but apparently causes micro tares in seals/gaskets etc, whereas glycol will swell them up, healing then as such.

The OAT I have experience with is the Nalco and the Pre-Max. Both fail water pumps pretty quick, and create leaks where none should exist. Corrosion protection with both was poor, but that’s also partly cause they are marketed as a long life coolant, but can’t last as long as they quote.

If its high in silicates, then it’s designed more for an alloy block or heads is my understanding. But that creates wear.

The advice I was given was to look for something that is ASTM D3306 or AS2108 compliant (as that green Penrite looks to be). Look for something with Borate over Phosphate. And usually the higher the glycol content the better.

I thought it was the silicate in OAT coolants that trash the seals as its abrasive.

both seem pretty similar then. The tectaloy has slightly more gylcol