Cooling fan permanently on from starting

hi guys, I’m new on here, and learning my way round my 90 300. Just changed my battery as last one was knackered. But noticed since I changed my fan comes on (from cold start) & stays on permanently. Have I knackered the temp sender.? I searched the forums but couldn’t find anything.
I’m guessing it isn’t likely to be overheating or knackered rad if engine is literally just started
Appreciate any advice..

Its Viscous fan mate or has it had a electric conversion ??

It’s viscous Kevstar..

Mtber said:

It’s viscous Kevstar..

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They spin all the time, stick a rolled up newspaper in it and it should stop spinning at idle speed.

bluedog333 said:

They spin all the time, stick a rolled up newspaper in it and it should stop spinning at idle speed.

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As above matey
Either that or it will be a paper white out lol

Mtber said:

It’s viscous Kevstar..

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Ok sorry for being thick but I do that before I start it of course, then remove it..

Ok great thnx for that will try tomorrow, visions of a snowstorm..

Mtber said:

Ok great thnx for that will try tomorrow, visions of a snowstorm..

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See if it turns by hand before starting the engine it should turn without moving the belt as they can seize up.

They work on a clutch so the faster the engine turns they lock up.

Er no, they are thermostatic, the hotter the air blown onto them from through the rad the more they lock up.
Mo

Got rid.. jeez took some bashing to loosen it though. Thinking will leave off and not replace as it doesn’t tend to work too hard. Any recommendations on replacement, beermach..? Not convinced about electric wud rather keep simple.

Got rid.. jeez took some bashing to loosen it though. Thinking will leave off and not replace as it doesn’t tend to work too hard. Any recommendations on replacement, beermach..? Not convinced about electric wud rather keep simple.

Mo Murphy said:

Er no, they are thermostatic, the hotter the air blown onto them from through the rad the more they lock up.
Mo

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they are thermostatic, but actually they work on the heat coming through from the water pump not the hot air from the rad

Mo Murphy said:

Er no, they are thermostatic, the hotter the air blown onto them from through the rad the more they lock up.
Mo

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they are thermostatic, but actually they work on the heat coming through the water pump shaft from the engine, rather than the air from the rad

Mtber said:

Got rid.. jeez took some bashing to loosen it though. Thinking will leave off and not replace as it doesn’t tend to work too hard. Any recommendations on replacement, beermach..? Not convinced about electric wud rather keep simple.

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What was wrong with it?

Get rid and fit an electric one - one with a switch to overide is the way to go

I would not mess around with the cooling system on a 300. I wouldn't fit an electric fan on a switch either, you can easily be caught out by that.

disagree - you need an overide switch if you fit an electric fan - last thing you want is for it to come on when you wading!!
Mines on a thermostat but I can start on a seperate switch and also de-activate - only way to go imho

Forestrax4x4 said:

disagree - you need an overide switch if you fit an electric fan - last thing you want is for it to come on when you wading!!
Mines on a thermostat but I can start on a seperate switch and also de-activate - only way to go imho

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Why? Do you wade through very hot water?
A thermostat is the way to do them, a switch alone isnt, thats what I meant.
Its easy to leave an idling vehicle unattended and return to it with the engine overheating, it needs to be autonomous.

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flat said:

they are thermostatic, but actually they work on the heat coming through the water pump shaft from the engine, rather than the air from the rad

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I haven't laughed that much in a long time, flat ! No really, I haven't, that's the funniest thing I've read in a long time
I'm guessing that you found that nugget on Facebook.
Mo

Mo Murphy said:

I haven't laughed that much in a long time, flat ! No really, I haven't, that's the funniest thing I've read in a long time
I'm guessing that you found that nugget on Facebook.
Mo

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Nope, not Facebook, why’s Facebook got to do with anything?

My belief, as I was told years ago was that it worked through heat from the water pump housing passing along the shaft and pulley etc and into the fan clutch bit and the hotter it got the more it locked up, pulling more air through the rad.

Relying on hot air through the radiator? How does that work. Got any links?