Radiator hoses - when last did you check yours??

[Turbo]

Hey all,

Just thought I would post something specifically for Cheetah owners running the rotax 912xxx engines.
When last did you check your radiator hoses? I decided it was time to delve into my engine bay and have a look around, specifically at the rear of the engine where something could be lurking....

Thank goodness I did, as I revealed yet another short sighted "design error" of the cheetah. Whoever designed the radiator pipe routing should be shot!!!

The number of pipes used first off is ridiculous, 18 clamps later and the same amount of possible failure points!!!! Secondly the hose inside diameter is incorrect for the pipework it is supposed to fit over! Lastly the pipe that routes out of the reservoir can on top of the engine toward the firewall, is a 90degree pipe, and clamps onto two aluminum pipes separated by another small piece of rubber pipe. This small piece of rubber pipe is clamped together in the middle of the engine mount lower point... Firstly you cannot get in there, and even with then engine out, it's tight!

The fact that this runs right next to the starter motor, and the aluminum pipe touches the starters one mounting bolt head, is another "design error" mine was almost worn through!!! Thank goodness I picked this up and rectified the problem. I routed the pipe work slightly differently to make sure nothing will make contact or get hurt during operation, ground ran the engine to temperature, flew 6 hours in the circuit at higher than normal throttle and blocked off some of the radiator to increase temps and water pressure higher than normal to see if there are any problems.

So far none, all is well!! I'm not sure if all the cheetahs are routed the same, but I would suggest you check your radiator pipe work for safety sake. Also replace your coolant - mine was still good, but drained and replaced all with new 96% concentration glycol.

Just my two cents worth hope it helps.

[Boet]

The 912 has a lot of "clutter" around it. I always try to "cut some of the clutter" as I belief it will be more reliable. I never liked that stoopid water pump outlet, that turns 90 deg and dives into tight spots wherever you turn it too. The rubber hoses WILL touch something and chafe....... Rotax does not supply a "straight" water pump, so I decided to make my own. Ahh, the convenience of one`s own lathe. Now no more pipes that chafes against anything, or complicated 90 deg rubber hoses. And as a matter of interest, the 90 deg inlet from Rotax goes for more than R1k. Crazy? Now do I hear the Rotax guys mumbling and grumbling about us making parts........