Radiator Fans switching on at different temperature

[alexcurtis]

Hi all

So the niggles are surfacing now after the rebuild! Its 1999 Griff 500

I drove to wales and back about 260 miles all and 100 of those going there was in heavy rain. I noticed that I could hear what I thought was a relay clicking quite a lot ( the wiring loom on the battery wont sit on top of it and keep falling out…) At the time I did not think much of it except don’t break down!!!

Then on the way home the fans kicked in at 70c ( on the car gauge) and then stayed on the whole way home which was not ideal as they are significant drain when they are running for 3 hours and its getting dark

Got home fine, and then next day started it from cold and watched what happened did exactly the same got to 70c and then the fans stayed on, so replaced the temperature sensor on the radiator, changed it when it was cold and did not loose any water.

Now the fans start up around 85c and click off at 80c. This is better as at least the fans are not running the whole time but the car has always run at 95-90c . The part I fitted is this from TVR parts

http://tvr-parts.com/tvr-parts/part-details/tvr-k0...

And it states it should activate the circuit at 95C.

So is it a faulty or incorrect rated new sensor? Or is there something else potentially faulty? As the in car gauge uses a different sensor is seems unlikely? that it could be that it becomes faulty at the same time….

Thanks in advance

Alex

[bobfather]

The cooling system has various and variable temperatures throughout the system. Yours is a '99 so the otter switch (fan switch) is on the side of the radiator. The gauge sender is in a dead spot near the thermostat. The gauge sender is known for reading artificially low due to its location and the cooling effect of air movement within the engine bay.

Before making any assumptions I would suggest you check the coolant temperature via Rovergage which reads from the ECU input which is a better quality better positioned sender. You should also think about doing the rover sender mod which swaps the gauge to a better positioned much more responsive sender position

Edited by bobfather on Saturday 17th September 18:53

[Steve_D]

There are also different switches.
Have a look at your new one which will have the on/off temperatures stamped on one of the hex flats.
May also be worth doing likewise with your old one.

Steve

[alexcurtis]

Hi problem solved I think Steve your right it was a different rated switch old was 95/90 new is 92/87 and looking at the bible it should have the new switch in all of the time and it's just that the gauge because of where it takes its feed from registers a 10 deg differenece when it's probably less, will get myself an adjustable resistor and do the little mod to get a better gauge reading

Thanks everyone appreciated, I will contact TVR parts and tell them as well their webpage is wrong! But supplying right part....

Cheers Alex