Follow up after coolant temperature exceeded

Hi Brian,

  assuming you are talking 255 F so only 123 c that is only slightly above the 120 deg max. I very much doubt that that has caused any problems.

I have set my limits as per the Rotax manual and the warnings at 20 deg c below max.

The bigger issue is figuring out why it was hot and what you can do about it, there are a number of discussions on this forum around that.

I thought you guys were in the middle of winter ? peak summer here so hot temps not unusual !

regards

Glenn

Thank you Glenn. Yes 255 degrees F. I'll look at setting mine 20 degrees C below. Yes we are in the middle of winter but have had some close to spring weather the last couple days. I had installed a cover from my plane manufacturer that partially blocks the radiator to provide better cabin heat and let the engine oil get higher than 160 degrees it was getting before to try and boil off any water that may have gotten in. With the Rotax I've gotten spoiled with not having to worry about temperatures while idling but with the cover on that is not the case. It was only around 63 degrees F OAT so not super warm but apparently too warm for an extended idle.

A couple of thoughts...

first undo the last thing changed so remove the cover !

secondly the "idea" that you need the oil up to boiling to get rid of moisture is total BS. Moisture will leave one liquid as soon as the partial pressure of water in one liquid is higher than the atmosphere....so even at 100 f so long as the air is drier than the amount of moisture in the oil it will dry out. So long as at the next preflight there is no creamy sludge under the oil cap then the oil is dry.

I have seen a rotax with a lot of moisture and sludge under the cap after sitting for a couple of years. We took it for a long flight 2hr+ and after that all the moisture was gone.

If you want a faster warm up there are a couple of oil bimetal valves that help

see aircraft spruce..

Down here in NZ in winter we put a little aluminium.....tape over the coolant radiator in winter to get about 90-100 c at "some stage" during the flight and remove in summer when temps are higher.

Thanks for the info. Good to know I don't need to worry about the moisture as much. Yes I'll be removing it unless it is much cooler out.

Brian,

The 912iS MML has specific inspections that are to be carried out if the coolant temperature is exceeded. The procedures are progressive depending on how hot and how long the event was. There is a graph in the 912iS MML, section 05-50-00, page 24, which directs your actions.  In this case you are directed to Table 1 on page 25 of this same section. Essentially you have to inspect the cooling system for leaks and check the torque of all cylinder head securing nuts.  If any nuts are found loose, then you must proceed to additional inspections as per Table 2.

I’m sure everything is fine since you were only 7 deg f over for a short time, but the inspections are easy to do. You should log this inspection in your engine log book.  I have seen overheated engines where all the cylinder head studs were loose as well as having water leaks at the cylinder head water tubes, but these were much hotter and longer events where coolant was lost.