G'day, I've got an eBay aluminium 3 core radiator with a 22x1.5mm threaded drain in the bottom and I would like to put a switch in it to turn a thermo fan on and off. I think on some cars this may be standard, and minisport sell a switch for this as well. The question is what temp range is ideal, and would this need to be different because the switch is in the lower cooler portion of the radiator. thanks

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1972 Mk3 Mini 1000, 1150cc supercharged.
https://www.ausmini.com/forums/viewtopic.php?f=3&t=95872

My thoughts.. the temperature range doesn't really make a lot of difference, so long as the fan comes on at a temperature higher than the thermostat's opening temperature, and turns off at some point lower than that. If the on and off temperatures are close together then it'll keep turning on and off and be annoying, and a decent gap between them means it stays on for a reasonable amount of time to bring the temperature down for all of the water in the system.. obviously once the thermostat shuts, if the fan keeps running its only cooling what is in the radiator, then the thermostat opens again and a rush of cool water flows through the motor. You could probably jump up and down and say that "thermal shock will do damage and blah blah" but yeah, whatever..

You'd expect that Rover put some thought into it and decided that turning on at 92 would be sensible, and turning off at 82 (being the standard thermostat closing temperature) would be the right thing to do.. I'd copy them. There is a cheap kit from Jaycar you can get that drives a fan with adjustable temperatures

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did I tell you that I won a trophy?

It can be somewhat vehicle specific and depends on the running temp.
To get technical the fan needs to be off while there is air flowing through the rad so highway and general driving over 50 or 60ish, but comes on to cool when at lower speeds, around town stop start etc.
On at 92 and off at 82 sounds about right but will depend 9n the normal runni g temp of your car. If you have an 82 Tstat then all should be good.
One thing to bear in mind is that the fans/switches were designed for front mounted rads.
And you will need to wire it via a relay so you could put an on/off switch on the dash to overide the sensor and turn the fan on. A 3 way centre off switch would give you complete overide if needed.

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Cheers Dave.

I've fitted a thermo fan on the inside of the guard, and used a Davies Craig thermo fan controller unit. Also using the eBay aluminium radiator.

https://www.amazon.com.au/gp/product/B0 ... UTF8&psc=1

It has all the necessary relays, etc as well as a probe that sits between the fins of the radiator. Wire it up, set the on temp and away you go. Just make sure that when you wire it, the fan is pulling air through the radiator from inside the engine bay, not blowing air into the bay.

Saves trying to add a separate temp sensor.

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67 Van, 1275cc

That's a neat solution Gambo, I may look at one of those. Cheers

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1972 Mk3 Mini 1000, 1150cc supercharged.
https://www.ausmini.com/forums/viewtopic.php?f=3&t=95872

Do you have any pics of how your fan is set up? Just getting some ideas together. I cut the louvres out to make some more room around the radiator but not sure if I want to mount it to the radiator (not sure there’s room) or just put it in the guard area, it wouldn’t be super efficient if not shrouded to the radiator I guess.

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1972 Mk3 Mini 1000, 1150cc supercharged.
https://www.ausmini.com/forums/viewtopic.php?f=3&t=95872

Mounting it to the radiator will cause a large hot spot in the middle where the motor is, and will cause overheating. there needs to be some space between the fan and the rad for equal air flow.

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Cheers Dave.

Here you go. Fan was just a $30 10" eBay special like this one - https://www.ebay.com.au/itm/AU-10-inch- ... 4b8b4cb858

This isn't for primary cooling, it's an additional that pulls air through the radiator when I'm not moving , so shrouding isn't as important. I could go to through the hassle of making a shroud, but this works just fine for me.

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67 Van, 1275cc

A 10" Spal slimline fan is a perfect fit between the radiator and the wheel well, I run one as the only fan on my engine converted deluxe, and have done for the last 5 years or so.

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Roads need more corners
A Deluxe(CG13DE), 2 Clubbies(998 and 1275) and 2 Morris 1100Ss