Fan Temp Switch

[Guest SEgan]

Hi all

 

Thanks to much help form this site my very slow build is get close to completion. Took advantage of the hot weather today to test the cooling system.

 

I have a coolman rad on a Pinto 2Ltr, in the top hose I have a temp switch for the fan from an Escort. When testing the system the fan did not come on. It came on if I shorted across the switch connections but the switch would not switch on the relay.

 

I removed the temp switch and tested it in a pan of boiling water in the kitchen (wife out!)

 

I had the following reading cold 26KOhms hot (boiling) 2.2 KOhms. Does this sound about right? I cannot find a spec for the item anywhere. Should the resistance drop lower than this when hot? or do I need to find a relay that will switch with a lower current?

 

Sorry this is all a bit long winded but in summary

 

Should I buy a new switch?

 

Thanks

 

Sean

 

[Longboarder]

Its supposed to be a switch, i.e. off/on! (infinity ohms/0.0something ohms)

 

That sounds like a temperature sensor you are using, not a switch. Should be open circuit, 0 - 90 or whatever temp the fan is supposed to come on and at 91 resistance should drop to virtualy nil and stay that way till it cools to say 85 then go open circuit again.

 

Nigel

[baj25]

Any suggestions as to what switch is suitable for this- from a scrappie of course!

TIA,

Brian

[Guest SEgan]

Bit the bullet and replaced the switch with a new one from my local suppliers.

 

The switch supplied is for a MK4 Escort.

 

Works perfectly , cost £5.29. I don't know if this is expensive but seemed worth it for a new switch and saved the hastle of climbing over lots of old cars in my work clothes!

 

Thanks for your help Nigel

 

Regards

 

Sean

[Guest Mike G]

Hi Sean

Alternatively, go for broke and fit an adjustable thermostat of the type available from Car Builder Solutions (www.nfauto.co.uk). I know their kit costs a hefty £25, but you have infinite adjustment on 'when' the fan can switch on/off.

 

Cheers

Mike G

[Guest salty_monk]

They work fine first time fitted but have a tendency to cause your hoses to "dribble" if you play around with the cooling system at a later date...

 

Dan

[Grim]

they certianly do! anyon reccomend some sealant?

[Jon Green]

Mine dribbles too! Any recommendation what temperature they should be set to kick in?

[Longboarder]

Engine silicon is good for sealing bigger gaps as it sets like bathroom sealant but is OK at higher temps.

I would say 90C for the fan on and fit a lower opening tstat than the standard sierra as pintos don't like to get too hot (details on NW Hoodies site). Fan should not be needed when the car is moving, only stationary and stop/start traffic.

 

Nigel