Expansion tank fitting

Hi Corey,

Whilst I have not seen anyone use the coolant level viewport to fit a temperature sensor, have seen a number of installs that use a 25mm barb to barb fitting in line with the radiator cooling hoses. You can get these fittings with a pre drilled and threaded port to suit a coolant temp sensor (some even come with a sensor) that way you still retain use of the coolant level viewport.

Quite a few of these on Amazon, eBay or motorcycle parts suppliers.

just a thought, might save you trying to identify thread types etc.

Regards,

Byron

Hi Corey,

I am curious - What information will a temperature sensor, in the expansion tank give you, that the existing head sensors don't ??😈

Thanks for the reply and the information Brian.

Because everything I read says temperature monitoring is required and critical in Rotax. And I fly in the  heat of the US Southwest. I had put a third temperature sensor in the expansion tank of my  912ULS as a back-up and a cross check to the two cylinder head temperatures. It worked out quite well. I can’t see the viewport on the expansion tank with my installation. I have to take the expansion tank cap off to check the fluid anyway ,  or remove the top  half of the cowling to see the viewport. 

When you say "It worked out quite well." In what way??

The reason I ask is ;

From my perspective your modification sounds logical - highest point in the cooling system, likly getting a "blended " coolant temperature representative of the whole system, etc

BUT 

Having gone down this enquiry track before, from memory, the response from the Forum Guru's was something like;

Rotax safe operating temperature limits are based on existing sensor location. Sensor information from other locations, within the cooling system, are not recognised by Rotax ie there is no empirical operational data for you, as pilot, to manage your engine from this additional sensor.

FYI; I fly in NSW, Australia, summer temps can reach 47C (in the shade) and are often 40+C.

😈