I am once again changing rubber engine components after 5 years -I bought the engine too early in my build.


My question: The two radiator hoses and two cylinder hoses I have removed show no signs, as far as I can tell, of any deterioration at all.


Is it possible to put the hoses "on condition' and monitor them rather than replace them at five years? That would only work if the deterioration was:


(a)  Visible to the naked eye if it occurs.


(b) The decay is gradual enough to be picked up by annual maintenance and give plenty of warning.


I've got the rest of the kit, so maybe I'm just lazy.

  • Re: Rubber Hoses - On Condition?

    by » one year ago

    The condition of these hoses is critical to the safe and reliable operation of the engine.

    The Rotax maintenance manual specifies the inspection intervals for these hoses and recommends replacing them at specific intervals or if there is any sign of damage or wear. The manual also specifies the type of hose material and the maximum lifespan of the hoses.

    Time limit The following components and systems must be replaced every 5 years:

    • All rubber hoses of the cooling system (except GENUINE ROTAX® silicon hoses), which need to be checked by "on-condition" maintenance according to the instructions of continued airworthiness.

    • All rubber hoses of the fuel system

    • All rubber hoses of the lubrication system which are part of the engine supply volume and if they are not in the maintenance schedule of aircraft manufacturer

    • Connecting hose of the air intake system • V-belt

    In general, rubber hoses should not be placed on condition. They should be replaced at the recommended intervals or if there is any sign of damage or wear. Rubber hoses can deteriorate over time due to exposure to heat, oil, and other chemicals. They can also develop cracks, splits, or other damage that may not be visible from the outside. Replacing hoses on a regular schedule helps ensure the safety and reliability of the engine. If a hose fails during operation, it can lead to loss of power, fuel leaks, or other problems that can result in a forced landing or engine damage. Therefore, it is recommended that Rotax 912iS rubber hoses be replaced at specified intervals or when there is any sign of damage or wear.

    It is not recommended to place Rubber hoses on condition, however, if you have the GENUINE ROTAX® silicon hoses (Red in color) they can be placed on condition and replaced when required. 

  • Re: Rubber Hoses - On Condition?

    by » one year ago

    OK, I continue with replacement this morning....

  • Re: Rubber Hoses - On Condition?

    by » one year ago

    Are there official ROTAX Silicon hoses for every hose that's rubber?  Do new engines come with rubber or silicon?


  • Re: Rubber Hoses - On Condition?

    by » one year ago

    Currently, the coolant silicone hoses (Rotax) are exclusively available for the 912iS and 915iS engines. On the other hand, silicone fuel lines are available for the 912UL and 912ULS engines.


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