Radiator Fan Switch

Simeon · Post by **Simeon** » Fri May 14, 2010 9:21 am

With a RV8 3.5 fitted to a kit car, what radiator switch on - switch off temp range should I be looking for? The Revotec adjustable switches are nice but pricey and as i'ts for road use only a bit of overkill

mrcheese · Post by **mrcheese** » Fri May 14, 2010 3:56 pm

I use one of these on a Land Rover.

http://www.x-eng.co.uk/X-Fan.asp

It can be wired up in a number of ways to give two diffrrent temperature ranges or operate a two speed set up.

I don't know what teperature range you are looking for though.

Ian Anderson · Post by **Ian Anderson** » Fri May 14, 2010 8:08 pm

I went to a local motor factor and asked for a Ford one
They got out the parts book and we looked at temp range - made the choice and it works fine

BUT
Make sure you run the fan via a relay - yes they can all handle 17 amps or whatever but not for long with the on off switching some get.

From memory the ford unit was about £12

IAn

Simeon · Post by **Simeon** » Sat May 15, 2010 8:14 am

Thanks for the input guys!

gelmonkey · Post by **gelmonkey** » Sat May 15, 2010 8:51 am

Simon
Have just read this thread and can tell you that Car Builder Solutions can supply you with a fully adjustable switch for about £18.
Just set your own temp range and away you go.

Audi A6,early Renault 5 fan switches work fine as well.
cheers
Paul

gelmonkey · Post by **gelmonkey** » Sat May 15, 2010 8:51 am

Simon
Have just read this thread and can tell you that Car Builder Solutions can supply you with a fully adjustable switch for about £18.
Just set your own temp range and away you go.

Audi A6,early Renault 5 fan switches work fine as well.
cheers
Paul

Will Reeve · Post by **Will Reeve** » Mon Jun 14, 2010 7:16 pm

My car currently runs a kelow adjustable with the push in hose in the rad. I am thinking of changing the switching to a more neat insert and temp switch as outlined above. I am running a 82C thermostat, wondering what the best fan switch temp would be.

There is a on at 87 and off at 82
on at 97 and off at 85

guessing the 2nd option?

mgbv8 · Post by **mgbv8** » Mon Jun 14, 2010 8:21 pm

Whatever switch you decide on. Just make sure that the thermostat is rated correctly. For proper control you need to be sure that the mechanical thermostat is fully open and flowing before you try to control the water temptwith the fans. Otherwise you end up with the fans running all the time with hardly any circulation ??

I use an 82C stat with my fans set to 90C.

Simeon · Post by **Simeon** » Wed Jun 16, 2010 9:34 am

Ok

For a SDI 3.5 I have a 74 degree stat correct?

How do I know when the stat is fully open?

Will Reeve · Post by **Will Reeve** » Wed Jun 16, 2010 9:46 am

I was recommended 82 for my SD1 lump in a TR7. You know the thermostat is open as the rad hoses are roasting hot.

seight · Post by **seight** » Thu Jun 17, 2010 3:16 pm

I thought 74 degree stat was common in a Westfield as there's not much room for a decent rad.

Mike

Will Reeve · Post by **Will Reeve** » Thu Jun 17, 2010 3:31 pm

I've never quite worked out what radiator size makes a different. I thought the thermostat sets the *minimum* temp of the engine? Assuming a huge radiator a 72 will keep the engine running at 72, 82 at 82 etc. Once the 'stat is open it doesn't have any effect on the max. temp of the engine?