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[amba]

What is it that causes the radiator fan to switch to its second stage(fast speed),as it seems in this recent bit of warm weather I may have the start of a cooling fan issue.

When I leave the car idling on the driveway,or even if I increase engine revs to warm it up quicker,I don,t seem to be able to get the electric radiator fan to cut in below a reading on the temp gauge above 95 c.

If I have been out temp against gauge is approaching 97.5 c especially in slow or stationary traffice but does come back down to 95 c when moving again.

Today after driving about 45 miles at steady 70 ish,I stopped up with gauge around 97.5 but when switched engine off main radiator fan was still running but only slow...sure I remembered last year it would be really crazy speed almost like jet engine.

Is the fan and second stage controlled by the top radiator thermo switch and can this temp be lowered some how to get second stage to cut in earlier or at a lower temp ?

[TheBoy]

High speed only operates with engine running (or ign on, cant remember), as soon as ign off, only slow speed comes on.

All controlled by the same switch in the radiator

[amba]

So my understanding is the top mounted radiator thermo switch controls the fans operation and switching.
Slow speed at 95 c ...high speed at 100 c and this will only run with the ignition/engine running.

Do these switches have a life expectancy ? and what if anything would cause them to have an irratic temperature sensing,or do they either work or not ??

[TheBoy]

So my understanding is the top mounted radiator thermo switch controls the fans operation and switching.
Slow speed at 95 c ...high speed at 100 c and this will only run with the ignition/engine running.

Do these switches have a life expectancy ? and what if anything would cause them to have an irratic temperature sensing,or do they either work or not ??

Switching points at just over midpoint, then just under 100C.

They tend to either work or not. Failure is often poor coolant servicing.

[amba]

Is it possible to get a thermo switch that will bring the fans on at a slightly lower temperature ?

[Dave DND]

The thermo switch, that appears to be functioning correctly by the sound of it, is probably far more accurate than the gauge you are watching

Wouldn`t mess with it personally - if it ain`t broke, nothing to fix.

[amba]

Fair call,Dave.

Just in the last few days when outside temp starting getting up a bit concerned that dial temp was rising  more than I remember....must have be soooooo low in the winter I have forgot what it used to be .

[Kevin Wood]

I am sort-of in the process of putting together a maintenance guide collecting all the information on fan electrics, as it's a bit of a rat's nest of relays, switches and fuses.

Hopefully, unlike most jobs I start, it will get finished soon.

Kevin

[o-meg-a]

Having removed my Viscous,
My temps which used to stay at 92 on the button all the time with the viscous,
Now start around 92 on the move on the flat....rising to around 95 on a long hill under load and rising to 98 on a standstill after a run, at which point you can hear the high power electric fan cut in, makes the engine dip slightly due to the load whilst standing.

Comes back down to 95 then untill i move off again.