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This guide will be detailing the installation I performed of a 16" Davies, Craig Thermatic Fan onto my wifes HR Holden. Before I start though let me say that on a HR Holden (and probably the earlier model Holdens also) the 16" Fan is much too big. I'd recommend either a 14" fan or two 12" fans (which is what I run on my car). Two 12" fans will fit the radiator width very well, a 16" fan will fit the width but is too high to fit infront of the radiator (flat) and too deep to fit behind the radiator. This shouldn't be a problem on models after the HR. This guide therefore gives basic thermatic fan installation but also show you what would be required to fit a large thermatic fan onto a smaller radiator like the HR without butchering the body in any way, I do however push the bottom of the radiator out and it makes the radiator sit VERY close to the water pump pulley wheel bolts. This guide also includes the installation of the Thermatic Fan Switch.

Note: Any image with an * in at the start of...

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The first step to fitting a thermatic fan is the same basic step to most cooling system upgrades, dropping the coolant out. As I usually say, when dropping the coolant try to catch it in a bucket unless you like working in water. You can drop the coolant from your system by removing the lower radiator hose at it's lower end, in this case at the radiator side. The radiator hose is held on by a standard hose clamp which can be loosened using a screwdriver. Once the clamp is loose you should be able to encourage the hose off with gentle persistance and harsh language.

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Since this job will include the installation of a switch I will also remove the top radiator hose from the radiator, this removal can be done using the same methods used for the bottom radiator hose.

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This fan will require me to remove the radiator from the car completely. If you are using 12" fans and installing them infront of the radiator (this is for HRs) you can remove the radiator bolts, lean the radiator over (you'll still need to remove the fan) and slide the fans through the gap, saving you from removing the gearbox oil cooling pipes (if you have them). It is still easier though to remove the radiator completely and place the fans on outside the car. I couldn't do that with this job though because I couldn't slide the radiator and fan through the gap even with the fan removed. The radiator can be removed with four bolts, one at each corner in the engine bay side.

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To remove the fan there are 4 bolts through the fan and pulley wheel into the water pump. Removing these with the radiator in can be quite awkward on a HR.

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The last step to removing the radiator (and removing the fan if it is too awkward with the radiator in) is to remove the two pipes for gearbox oil cooling. Be prepared for these to drip gearbox oil though, you can either put a rag under them, clog them up with a rag, screw a plug into them or simply tuck them upwards out of the way.