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V8-250 Saloon: Radiator Fan Temperature Switch

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classiclife
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V8-250 Saloon: Radiator Fan Temperature Switch

Post by classiclife »

Hello,

For those owners running their V8-250 saloon with an electric fan AND with the fan temperature switch located in the BOTTOM of the rad - what temperature range did you opt for on the switch, please ??

I have generally fitted a 86 to 95 on other classics which has proved effective and efficient; i.e. the fan cuts in at 95 degrees and cuts out at 86 degrees, this takes in to account a thermostat rating of 82 degrees being used.

I'd be very grateful to know your choice.

Thank you in advance.

Richard.
1968 Daimler V8-250 Saloon
DLOC East Sussex Branch Secretary
DLOC 2.5L V8 & V8-250 Registrar - https://www.dloc.org.uk/v8-250
DLOC 2024 International Rally - https://www.dloc.org.uk/rally-2024

Bob Aylward
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Joined: Sat Apr 02, 2016 12:48 pm

Re: V8-250 Saloon: Radiator Fan Temperature Switch

Post by Bob Aylward »

Hi Richard,
I live in the western suburbs of Sydney, Australia and I have a 1966 2.5 litre v8 saloon, it always suffered in the summer heat here and I installed a Kenlowe Fan in front of the radiator and the thermostat in the top of the radiator where the engine temperature is apparently measured more accurately. I have a 70`thermostat and the fan set to switch on at 85` and off when the temperature comes down to 85`. This has worked really well in our summer temperatures and with the whole cooling system in good shape the fan doesn't get used in any of the cooler months but is good insurance when we have 40`days in summer. I found that the Kenlowe fan at 13" diameter was ideal for the car as the aftermarket fans available here were either 12" or 14" diameter which made them to small to do the job or too large to fit in front of the radiator. I still have the normal viscous fan on the front of the motor and can safely say my car runs at 70`always even in the summer heat. Good luck with your project.
Kind Regards, Bob

classiclife
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Re: V8-250 Saloon: Radiator Fan Temperature Switch

Post by classiclife »

Hello Bob,

Many thanks for your reply and giving an insight with your current set-up; much appreciated and this sounds encouraging.

Having removed both cylinder heads the other day and the viscous unit; it is my intention to fit the fan between the engine and rad without replacing the viscous unit. There is certainly sufficient space to do so.

The radiator is in top condition and the rad sensor will go, as mentioned, in the bottom.

It will certainly be an interesting comparison for our two cars, as you have exactly the opposite of my intended set-up.

Will keep you and the thread updated as to how this intention pans out.

Best wishes.

Richard.
1968 Daimler V8-250 Saloon
DLOC East Sussex Branch Secretary
DLOC 2.5L V8 & V8-250 Registrar - https://www.dloc.org.uk/v8-250
DLOC 2024 International Rally - https://www.dloc.org.uk/rally-2024

Paul Edginton
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Joined: Sun Feb 14, 2016 1:56 am

Re: V8-250 Saloon: Radiator Fan Temperature Switch

Post by Paul Edginton »

Hello Richard,
It seems rather counter intuitive to mount an electric fan infront of the radiator where it will block the atrflow.
As shown in the forum previously I mounted mine just inside the aperture of the shroud as a puller fan.
About the only time it comes on is in heavy traffic and is very effective so there is no need to run the standard fan as well.
Cheers
Paul

classiclife
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Re: V8-250 Saloon: Radiator Fan Temperature Switch

Post by classiclife »

Hello Paul,

I fully agree with that and I've never been an advocate of fans in front of rads for the very reason you point out. In some cases there is no alternative, but where there is, the fan fitted between the block and rad is the way to go IMHO !!

Best wishes.

Richard.
1968 Daimler V8-250 Saloon
DLOC East Sussex Branch Secretary
DLOC 2.5L V8 & V8-250 Registrar - https://www.dloc.org.uk/v8-250
DLOC 2024 International Rally - https://www.dloc.org.uk/rally-2024

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John-B
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Re: V8-250 Saloon: Radiator Fan Temperature Switch

Post by John-B »

Electric fans and sensor position are two of the subjects that cause a lot of disagreement :D

I disagree with the above on both points :o

If the fan is a push fan in front of the rad it will have most effect as a fan behind will be trying to pull with the airflow but that's not quite as efficient as pushing. If the fan in front of the rad disrupts the natural airflow, and the coolant temperature is still normal, then it doesn't matter that the fan is slowing the natural airflow and the fan won't come on. If the coolant temperature rises because of the front fan slowing the natural airflow, then the electric fan comes on, so no problem!

If the temperature sensor is in the bottom hose it will sense the temperature AFTER the rad has tried to cool the coolant as much as it can, as the coolant goes back into the block, and therefore is in the best position to add top-up cooling by switching the fan on.

If the sensor is in the top hose, it will switch the fan on before coolant enters the radiator, which means it probably works harder than necessary as the rad isn't needed so much as the fan does most of the work and leaves the rad less to do!

However, a lot of people including my engine restorer put the sensor in the top hose as it's more convenient and I don't think it makes any real difference. It just means the switch cut on and off will be slightly different for each sensor position.

My electric fan is in front of the radiator in my Dart and I like it there because it's hidden.

classiclife
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Re: V8-250 Saloon: Radiator Fan Temperature Switch

Post by classiclife »

Hello John,

Thanks for your reply - as you say, it is a subject with many different views and preferences.

I guess my overall view is this: if the electric fan and coolant system do as is required, then the goal is achieved in full - nobody likes to see a temperature needle heading to the red !!

Best wishes.

Richard.
1968 Daimler V8-250 Saloon
DLOC East Sussex Branch Secretary
DLOC 2.5L V8 & V8-250 Registrar - https://www.dloc.org.uk/v8-250
DLOC 2024 International Rally - https://www.dloc.org.uk/rally-2024

Warsash 2
Posts: 332
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Re: V8-250 Saloon: Radiator Fan Temperature Switch

Post by Warsash 2 »

Hi
What is not always appreciated is that the prime coolant is the engine oil which needs to be clean and topped up. The other coolant is the airflow through the radiator and around the engine. The fluid which I think is misnamed as the coolant is just a transfer medium. So in the end the airflow is the most important secondary cooling. On both my V8 and Margarets SP the electrics fans are infront of the radiator. In the case of the SP as it has R&P steering which means the original fan is removed. The Sensor for both fans is in the top hose and set at normal as I prefer the fan to come in little and often rather than fight an already overheating engine.
Just a thought!
Colin

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