After loosing an engine due to heat, plus the fact that I'm now on the "I want more power" trip.. the flavour of the month has been to look after and/or upgrade the cooling system.

After a mate of mine looking under my bonnet and saying "when are you going to get rid of that stupid thing and get a thermo fan", I decided to look into this and see why the heck I would even bother. The first obvious advantage, is you are putting less strain on the engine to spin a fan, and putting the strain on the battery to spin a fan to keep the car cool. This might seem all very well and good, but you're also taking alot of power from the battery, and requiring (perhaps) alot from your alternator, right? Wrong.. well.. its wrong depending on your installation. The benefits of a thermo fan exist only when you're using them the way they are meant to be used, and that is to have them set up to only operate when required. (Rather than spinning all the time, unlike the engine/water-pump mounted fan). You really don't want them operating non-stop anyway, the engine is designed to operate at a normal temperature, if you lower that temperature the ECU is likely to pump in more petrol and have a negative impact..

I first did some research into the Davies Craig range of fans, and after someone else's advice, I looked into a pair of 12" Thermo fans.. they cost like AU$200 each.. and seemed a bit exy.. I looked around for better pricing and found out, after a bit of research, that a 16" thermo fan provides 120% of the cooling effect of TWO 12" fans. (so in effect, a 16" thermo fan has 240% better cooling than a single 12" thermo fan, if my maths is correct). Plus, you can get a brand new 16" thermo fan for approx $300.

The process is a bit like this... get your 10mm spanner and undo the four bolts on the fan attachment to the waterpump.. its a bit tricky because you won't have removed the plastic shrouding thing that covers it.. but you tend to need to get the fan off before you can pull that shrouding out. Once you get the fan out, there's 4 screw/bolts.. two at the top, easily accessible, that join the plastic cover to the radiator.. the other two are down the bottom but on the side, and are a bitch to get to.. once you get that out, put the other 4 nuts that were supporting the fan back on all the way and up tight.. and that's that.

Now to get the thermo fan installed.. I found the easiest way to do things, was to simply remove the top two brackets supporting the radiator, and then pull the radiator slightly forward, rather than removing it completely. There are extremely long bolts supplied with the thermo fan usually, and they are too long (especially with the clearance you get while simply pulling the radiator forward.. find some about 3/4 or 1/2 the size of the ones supplied (or just work out how long you need them to be). I lined up the thermo fan on the radiator and found that the bottom bit of the fan protrudes a little down the bottom.. only a little, but worth mentioning. Getting the bolts through the radiator core is easy enough, line up the fan where you want it, and push the bolts through (lining the bolts up on the thin fin stuff that is brittle.. it should push through rather easy between the bar/core bits).

Once the holes are basically made, I pulled the bolts back out and pushed them through from the other side.. you don't want bolts sticking out straight into the air conditioner cooler.. you need to make sure that the fan doesn't bend or twist during the installation also.. I had to use some washers on a couple of the bolts to ensure the fan was sitting flat. You tend to get good instructions when purchasing the fan.

Note, to install the fan on the back of the radiator, you need to reverse the polarity and you MUST flip the fan blade prior to installation.. if you only reverse the polarity, then it will work less than 50% as well as it should. Once again, I learnt this the hard way.. after following a pathetic salesman's advice of "just reverse the polarity and she'll be right" and finding that the fan's contents had fallen out at some stage and instructions were missing.. once conferring with www.daviescraig.com.au .. I discovered that flipping the fan blade was a MUST.





This is an overall shot.. the fan is there, trust me.. certainly opens up a bit of clearance between the radiator and engine.. which makes it easy to understand how some people can fit a straight 6 cylinder engine in there. 


Note: When you do the bolts on the radiator brackets up the top here, you will find they are brittle and will break easily if you do them up tight, be careful.



The next thing I did, was install the thermo sensor... the major thing to worry about was getting the sensor into the coolant return line.. I found that the rubber thing they supply to help close up the gap while shoving it in there is good and all, but mine leaked originally, and if you do a clamp up too tight towards the end of the end tank, the end tank will crack or a bit will break off.. I learnt this the hard way, yet didn't break anything substantial and moved the clamps back further, which would have been a good idea from the beginning.. and I used two for safe keeping.. you really need to do this and check on the car after a breif drive, and having it just run in the driveway, and then check it after a decent drive when there's a bit of pressure there.. the last thing you want is for coolant to leak out the top here.. and I had some troubles with that. Here is the sensor wire and two clamps on the top coolant return line:


And I setup the thermo relay switch just in front.. was a tad tricky working out where to put it.. 


The thermo sensor's settings are what you need to get spot on, and takes a fair bit of adjustment.. basically it should make the fan operate rarely, and for small amounts of time. ie, when you're just cruising around the city, off boost or just driving through the suburbs calmly, it shouldn't operate at all.. when you stop at a set of lights you should expect it to come on if you're sitting there for more than 10 seconds or so.. basically it needs to switch on right before the 3rd line mark in your temp guage (not including the bottom, zero mark)... the fan isn't required very much... If you hammer it, and you're on boost alot, then you can expect it to be going on/off quite alot.. think about it.. when you're on the highway, or on a normal road, doing 70-110 km/h.. just cruising.. the airflow of the car's movement is more significant than what the fan can acheive (or very close to what the fan can acheive) and isn't required.. this is what a thermo fan is all about, the fact that a fan on the radiator isn't needed non-stop.. 

Furthermore, I installed a 10" thermo on the front of the airconditioning cooler.. which improves how cold the aircon is significantly and improves airflow with the other fan so its not just fighting for air through both the coolant radiator and the aircon cooler (and the front mount intercooler in my case). Very hard to see the bloody thing, so hard to get a photo..


Note: The wiring diagram for the combination of both fans, or one fan on its own etc, are all included in the kits with the fans, along with relay, all wiring neccessary etc.. I found the instructions very thorough and precise.

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