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Comment by Calvin Penner on September 29, 2014 at 9:03am

Thanks guys for your replies. My oil temp has gotten up to 245 f but it was still going up while flying level so i didnt want to heat it more than that and landed it after 20 min flight. The water temp is staying on the cooler side i dont remember the exact number. Sounds like i need a bigger radiator and thats what i needed to hear since i was not sure wether it was not getting enough air through or the rad is to small.

Comment by Jerry Latimer on September 28, 2014 at 1:15pm

I had overheating problems with my 912 powered HDS also.  On my second flight oil temps climbed to 260.  This is the redline for the Rotax.  I kept making the cutout in the cowl larger but could not fully resolve.  My temps would be around 215 in level flight on 100 degree days.  If I climbed, the temp would rise to 230 which is the top of the green on the Rotax after about 1000ft.  I would level off.  Cool the oil down and climb another 1000ft.  I finally had to install the largest oil cooler that Rotax makes.  On the original FWF kits Zenith supplied the middle size cooler which is not large enough.  To install larger cooler required modifying the cowling the accept it.

The FWF kits have a much better set up and use the larger oil cooler.

Comment by Christopher Jon Brown on September 25, 2014 at 11:30pm

How hot is it getting?  Mine has got as hot as 239 degrees on a 102 degree day.  So cut my bottom cowl opening a little bigger and put a 2 inch lip on it and goes to around 233 degrees on a 100 degree day now.  I saw some forums on RV-12's that go to 250 degree oil temps, so how hot are you going. Also my plane is a 750 which is quite a bit slower, 100 mph max.  Also what is your CHT?  Are you full of oil? There are no sharp bends in the oil lines?