SPA Temp Gauge

[WIL35]

Hi owners of Cerbs with SPA gauges!

My Cerb has a SPA oil pressure and water temperature gauge and I notice that there is a consistent 10 degree difference between the gauge and the ECU temp reading. The gauge reads 10 degrees lower.

The ECU switches one of the fans on at 84 degrees while the gauge is reading much lower. I cleaned the SPA sensor when I changed the coolant recently, but it looked fine.

Can I test the SPA sensor, is it likely needing replacing, could it be an earth problem or can the gauge be re-calibrated? I know it's kind of ok, seeing as I know that it reads low, but I would quite like it to be a little more accurate.

Thanks

[Jhonno]

Have you checked/changed the ECU sensor?

[camel_landy]

You could do with checking the actual temperature with a known-good device. IR thermometer guns are perfect for this.

M

[WIL35]

Jhonno said:

Have you checked/changed the ECU sensor?

Is it possible to check it if the ECU temp reading does actually rise as it gets hotter? It's just is it working 100% properly I suppose.

Might be worth just changing anyway. Presumably it could be swapped 'very quickly', to avoid draining/refilling the system again?

[WIL35]

camel_landy said:

You could do with checking the actual temperature with a known-good device. IR thermometer guns are perfect for this.

M

That's a good point. At least then I would know if either was correct. I'm off to search IR Thermometers. Unless they are more expensive than just changing both sensors.......

[pmessling]

I have checked both my SPA and the ECU temps in the past and there is a different, although max 5 degrees. That's running the Bosch motorsport sensor.

Unless you had both calibrated there is always going to be a difference, but as long as your aware of it then there is no real issue, both are more accurate then the original guage.

[pmessling]

[Adambul]

I have the same issue and after a reasonable amount of testing I have concluded that it’s down to the length of the temperature probe. The original probe is much longer, hence the length of the takeoff branch. On the original gauge the temperature probe is therefore in the water flow. The SPA gauge has a much shorter probe and when installed in the same position is out of the water flow by nearly 2” and this I believe is why it is reading lower. I’ve been considering moving it to one of the water rail air bleeds as I like the SPA gauge and the oil pressure reading is far more accurate, although this may then cause issues bleeding the system.

[gruffalo]

My SPA water temp reads 10 Celsius below the ECU temp reading but is bang on at low temp, eg 25 Celcius day and the car will SPA reads 25 on initial start up.

I have been meaning to see if something can be done about it for about 6 years just never quite get round to it.

One day I may.