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My oil temperature started overheating (around 233). I don't know what temperature it was before the overheating issue started, but it was definitely not this high.  It turns out I had a radiator leak. One of the thin tubes in the cooling area of the radiator had cracked and was the cause of the leak. I have to admit I flew it several times trying to figure out what was going on. It did not seem to be leaking badly. I replaced the radiator, used coolant Dexcool 50/50 mix, changed the oil, oil filter, gas filters, spark plugs and cleaned out the oil sump.

My engine continues to overheat (233) during level flight, RPM around 4800, outside temp 60 or lower. (Same temperature as before replacing the radiator and oil.)  I am flying in the northeast where temperatures are fairly cool here this time of year (50-60 F). I bought the gyroplane in Florida in March and flew it up north. Never had an overheating issue in the hot Florida weather or the the summer in NJ.  

I am new to Rotax engines. My gyroplane uses a 914 and has around 150 hours on it. Engine is in a pusher configuration. See attached photo. 

Some questions:

How do I tell if I have an coolant system problem or an oil cooling problem. 

What do I do to measure coolant temperature? Is the CHT the appropriate gauge for measuring if the coolant system is working properly. (note that the CHT never indicated high temperatures when the radiator was leaking.)

Do I need to purge the oil system? If so, what are the tricks and where is a good video for learning how to do this. 

The big question is why is my oil overheating in cooler weather with a new radiator. 

Thank you for your help!

 

  • Re: High Oil Temp

    by » 5 years ago


    It seems to me that if your CHT is in the green, then the water cooling system is doing what it is supposed to do. Do you have EGT gauges? If so, what have they been showing?

     


  • Re: High Oil Temp

    by » 5 years ago


    4800 rpm is too low for sustained cruising, which lugs the engine and may be the cause of your overheating. Reduce the prop pitch to get more like 5200 rpm in cruise.


  • Re: High Oil Temp

    by » 5 years ago


    Thanks for the responses. I do have an EGT gauge, I do not know what the temperature has been running, but I know that it has always been in the acceptable range.  I know I am sounding like an idiot, but I don't know what the good and bad temperatures are for these various sensors. I have a digital screen showing the values. The numbers turn from green to yellow if they are not within the correct range. Everything is green but the oil temp. It turns yellow at 230 degrees. 

    I have readouts for oil pressure, fuel pressure, oil temp, CHT and EGT.

    I also have Engine RPM and MAP.

     


  • Re: High Oil Temp

    by » 5 years ago


    I can cruise at 5100 RPM. I have been running the engine slower thinking I was helping the situation. 

     


  • Re: High Oil Temp

    by » 5 years ago


     this is big problem with pusher configure aeroplane. 

    the cool air can not properly cool the ENGINE as well as radiator.

    the quantity of fresh air throw on radiator is mentioned in book. i.e CFM require........

    so change the fresh air cooling duct. hope all will be settle.

    50/50 DEX COOL. is best one.


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