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Joe Blow wrote:My hot tip is to use thermal conductive paste on the probe (if it is an "insert into the cooling fins" style one), like they use on computer heat-sinks.

That seems a bit different aye! I've actually got some thermal paste around so might slap some on it. Don't see how it can hurt Nice bay bro!

Thanks for the info guys

I find this strange that it's saying to set the sensor probe as close to the top hose as possible.... I don't really get this..... I think the bottom hose is the best place to place a e-fan sensor ( or very close to it).......

I think top is better or you are sensing cooled temperature not engine temp. Gauge senders are normally at the top of the engine.
Thinking about it I don't think it matters if you can control when the fan kicks in ???

but isn't it better to measure the temp of the coolant going into the engine than coming out of it? the fan is there to assist the rad and only needs to run if the rad fails to cool the coolant efficiently... slow speeds, traffic etc. if it's in the top hose, once the stat opens, the fan is going to be running nearly all the time unless the controller is set high so it only kicks in once the engine starts to overheat. In the bottom hose, the controller should only kick in if the rad fails to do it's job and the fan should run less often.

The fan should be set to kick in above normal running temp, mine hardly ever kicks in (just under half way on the gauge). If it is set to kick in before overheat I can't see a problem with using either hose.

ian65 wrote:but isn't it better to measure the temp of the coolant going into the engine, coming out of it? the fan is there to assist the rad and only needs to run if the rad fails to cool the coolant efficiently... slow speeds, traffic etc. if it's in the top hose, once the stat opens, the fan is going to be running nearly all the time unless the controller is set high so it only kicks in once the engine starts to overheat. In the bottom hose, the controller should only kick in if the rad fails to do it's job and the fan should run less often.

^ I hear ya, but top hose seems to be industry standard, after all you are trying to regulate the engine temp, not the radiator.
But the idea interests me. Where have you got yours mounted Ian?

myatt1972 wrote:The fan should be set to kick in above normal running temp, mine hardly ever kicks in (just under half way on the gauge). If it is set to kick in before overheat I can't see a problem with using either hose.

Mine too, 13bt running a koyo twin pass rad though, it only needs to kick in for about 30seconds every few minutes when stationary on a 35c day.

Joe Blow wrote:

ian65 wrote:but isn't it better to measure the temp of the coolant going into the engine, coming out of it? the fan is there to assist the rad and only needs to run if the rad fails to cool the coolant efficiently... slow speeds, traffic etc. if it's in the top hose, once the stat opens, the fan is going to be running nearly all the time unless the controller is set high so it only kicks in once the engine starts to overheat. In the bottom hose, the controller should only kick in if the rad fails to do it's job and the fan should run less often.

^ I hear ya, but top hose seems to be industry standard, after all you are trying to regulate the engine temp, not the radiator.
But the idea interests me. Where have you got yours mounted Ian?

myatt1972 wrote:The fan should be set to kick in above normal running temp, mine hardly ever kicks in (just under half way on the gauge). If it is set to kick in before overheat I can't see a problem with using either hose.

Mine too, 13bt running a koyo twin pass rad though, it only needs to kick in for about 30seconds every few minutes when stationary on a 35c day.

mines in the bottom hose. It's all interconnected I suppose but the stat and rad controls the engine temperature and the fan is there merely to assist the rad. The temperature of the coolant coming out of the engine is always going to be hot, it the temperature of the coolant going back in that's important as far as a e-fan sensor is concerned..............I , er, think

I hear both Points of view, but I think it should be at the closet point to the increased temp (that will be once the thermostat can no longer control the temp) which for ease this will be near the Top House?

On both the Rotary Bikes with e Fans I had, both sensors were on/near to Header.

Pete

DKWW2000 wrote:I hear both Points of view, but I think it should be at the closet point to the increased temp (that will be once the thermostat can no longer control the temp) which for ease this will be near the Top House?

Pete

once the engine is up to operating temperature, the rad then controls the temp. the fan shouldn't be needed unless the rad becomes inefficient at cooling which is when the fan kicks in so the fan needs to detect the temperature of the coolant exiting the rad before it goes back into the engine. I still can't see any benefit to a fan controller measuring the temperature at the top hose before it's had a chance to be cooled by the rad. Does the fan need to be operated by engine temperature or coolant temperature?
I would say coolant temperature as the fan is only supplementary to the rad.

DKWW2000 wrote:
On both the Rotary Bikes with e Fans I had, both sensors were on/near to Header.

Pete

Why though?

I had never thought of it that way aye, Ian. But I can see the reasoning for it