912 Coolant Pressure Test

Question:

Jim Leon asks: Does anyone know where to purchase a radiator pressure tester that will fit a Rotax radiator? I have 3 kits and not one will fit. Thanks

Answer:

Hi Jim,

The kit we use includes a universal rubber adapter that expands as it's tightened to securely seal against the coolant expansion tank. However, we had to trim the rubber slightly so it would fit properly inside the tank and ensure a secure seal.

The specific kit we purchased is the STANT ST270 (12770) Cooling System Pressure Tester Kit, which includes the rubber adapter mentioned. Please see the attached photos of the kit and adapter for reference.

That said, according to the Rotax Line Maintenance Manual (LMM), the correct procedure for pressure testing the coolant system is not performed through the expansion tank. Instead, the pressure test should be conducted through the coolant hose at the upper outlet elbow on the cylinder head (see attached excerpt from the LMM).

The specified limits for the coolant system pressure test are as follows:

Minimum relief pressure: 1.2 bar (17.4 psi)

Maximum relief pressure: 1.6 bar (23.2 psi)

Here are a few helpful forum discussions that provide additional information related to the coolant system:

• Rotax 914 coolant pressure: https://www.rotax-owner.com/en/912-914-technical-questions/8364-rotax-914-coolant-pressure

• Coolant pressure and temperature: https://www.rotax-owner.com/en/912-914-technical-questions/6263-coolant-pressure-and-temperature?start=5

 Let us know if you have any questions!