Zetec Fan temp switch

[leegav]

I know a 2l zetec blacktop runs hot at 95 ish at the head..
My question is if the fan temp switch is not in the head its in the top of the rad what temp should you run on a switch.
My guess would be 82 to 72 or would 88 -82 be better suited?

[Dick]

If you run the lower temp one the thermostat in the engine should keep the engine at its running temp of 95 ish. But its can only be judged when your running in normal climate you dont want to keep cooling the water down to low if its not needed as you then end up having to warm it back up and if your doing this your losing power.

[andyf]

It needs to be over the thermostat open temp. My pinto has a 82 thermostat and the fan switch comes on at 86 and off at 82. There is a table on turbosport that lists the available switches and their on/off temps. If you look in the zetec section they may even have suggestions.

[steve m]

I don't remember what my sensors work at, but I have two of them, one in the rad half way down, and one on the water filer on the top of the engine, (crossflow engine)
both are wired in parallel, so if either detects it needs to power the fan it does
overkill yes, but as both the filer and the rad had a big hole for a sensor, I wired them both in

steve

[Fury1630]

^^ I have something similar, but the second switch is the ECU reading the water temp direct in the head, again either will switch the fan. You can have as many switches as you want - there's a port in most zetec thermostat housings a switch can be screwed into, as long as they're all in the earth line & the fan has a live-with-ign (or even a permanent live if you want it to carry on cooling after the engine's off) each switch will turn the fan on & off as it sees fit. Chances are though that only one will switch the fan on, but at least there's a fail-safe.

[andyf]

Having the fan run on after the engine is switched off only helps if you are running an electric pump to circulate the water while it's being cooled. The stat must be open and the water circulating for the fan to be effective.

[David T]

Fan running after engine switch off does help cool the engine bay on a hot day and reduce heat soak. A proper branded fan makes all the difference to cooling.

[leegav]

Thanks guys.
At the moment due tona switch failure i had the fan wired upto the battery via a fuse and a switch. An i turned it on when it got too hot. Problem is its a tedious job when strapped in as my switch is under the dash.
I have the standard zetec thermostat so will get a switch that runs above this..

What are peoples thougjts on removing the stat? It never used to run a stat when it was racing...

[leegav]

If you run the lower temp one the thermostat in the engine should keep the engine at its running temp of 95 ish. But its can only be judged when your running in normal climate you dont want to keep cooling the water down to low if its not needed as you then end up having to warm it back up and if your doing this your losing power.

If i run the lower switch would this mean the fan will run constantly when the thermostat is open. If the thermostat is a 92? If the thermostat is 92 shouldnt the fan be above this temp? Say 98 - 92
Uurgh this is confusing now.

[Dick]

The switch only controls the fan it will have no effect on engine temp unless you are stuck in traffic and the engine is just sitting running and the fan switch you are using is higher than your required engine temperature . Once you are driving at (they say anything above 25 mph) the fan is as good as useless as the air is being pushed into the radiator via the forward movement providing the air can flow . So it wont matter what switch you have to control the fan. The thermostat on the engine will open and close to maintain engine temp. The cold water that returns to your engine when driving is not the temperature of the fan switch or the thermostat its dependant on the efficiency of the radiator and the cold water at the bottom of the radiator. Have a lower temp switch than required is not a bad thing as it will pass air over the engine when stuck in traffic keeping the engine bay cooler, Its also not a bad thing if it runs on as David has said to disperse the heat under the bonnet.
Ask yourself when you was racing and you had the fan on all the time did the engine run cold or was it near normal . Removing the stat is not something i would advise for general use and if you do you can give yourself bigger problems.