on off switch for automatic fan relay?

There was a Kenlowe electric fan fitted to my 90 on purchase and I have replaced the wire thermostat in the top hose with an X-Eng thermoswitch in the bottom hose, so it comes on automatically when the coolant in the bottom hose is about 90*. It is wired so runs when the engine is off if the temp is still high. It very rarely comes on, mainly in traffic jams, and then cools down to 80* in a few seconds.
I would like to install a switch so it runs automatically but I can switch the fan on in advance i.e. see heavy traffic jam ahead so turn on before the temp rises. The ability to turn it off as well e.g. for wading for instance, would be useful too.
I think that if I put an override switch between the thermoswitch and the relay I could turn it on independently of the thermoswitch but how to turn it off independent of the thermoswitch?
Thank you.

capo said:

have replaced the wire thermostat in the top hose with an X-Eng thermoswitch in the bottom hose, so it comes on automatically when the coolant in the bottom hose is about 90

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Lots of views on if it should be in top hose or bottom. I honestly don’t know the answer. (Prefer top) But personally if it’s out the bottom at 90° it’s getting close to too late, for me.

capo said:

I would like to install a switch so it runs automatically but I can switch the fan on in advance i.e. see heavy traffic jam ahead so turn on before the temp rises. The ability to turn it off as well e.g. for wading for instance, would be useful too.

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Have you a relay in the system? 3way switch would sort that.

J

Would this help

https://www.ebay.co.uk/itm/Revotec-...467910&hash=item5468cf4653:g:hz4AAOSw-L5bxc82

gstuart said:

Would this help

https://www.ebay.co.uk/itm/Revotec-...467910&hash=item5468cf4653:g:hz4AAOSw-L5bxc82

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I was thinking less than a fiver, but yes

J

Hope this also helps

This product must be used with a Revotec electronic fan controller.
So £48 for the switch, another for the controller! I already have an X-Eng one.
Or....... Ritchie-asg1 on LRUK suggested a 3 way switch, mid position off, top connects thermostat to relay, and bottom connects to the relay - so it is switched on the same way as the thermostat would. Supply the relay with a fused live supply, and have the thermostat switch to ground the operate the relay, and then have the switch also connect to the thermostat or ground, or open.

marjon said:

Lots of views on if it should be in top hose or bottom. I honestly don’t know the answer. (Prefer top) But personally if it’s out the bottom at 90° it’s getting close to too late, for me.

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It's a V8 so have the switch set to on @ 88, off @83; the 90-80 mentioned above is the VDO reading from the engine but has the original Disco sender which isn't properly matched to the gauge. Can be set to 92-87 but that is too high for my liking.

Ideally, if I can find a shroud/cowl to fit I'd put a viscous on; problem is the neither the shroud from the Disco nor a Defender V8 would line up on the rad with the fan in the correct place.

Not wanting to start another debate about which is best, but my preference is viscous no matter how well the electric works. I'd rather a V8 is kept cool all the time than allowed to get hot and then be cooled down.

@gstuart

Many thanks, just what I wanted.

capo said:

Ideally, if I can find a shroud/cowl to fit I'd put a viscous on; problem is the neither the shroud from the Disco nor a Defender V8 would line up on the rad with the fan in the correct place

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The 630 runs an electric fan, the shroud which covers the non fan area has hinged flaps (obviously they open with airflow)

capo said:

I'd rather a V8 is kept cool all the time than allowed to get hot and then be cooled down

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Agree not going to debate, preference peace of mind for me.

J