Oil Temperature during Climb

What airplane are you flying?  For instance... early RV-12 models had oil cooler positioned very close to front of muffler.  Solution was to either buy new exhaust system to relocate muffler further aft, or modify lower cowling and move oil cooler 1" further forward.  I did the later and all is good now.  You might want to consider using Mobil 1Racing 4T Motorcycle 10W-40 Full Synthetic Oil.  This oil is good for engines that share oil between crankcase and gearbox.  Synthetic oil is good for high temperatures Vs. petroleum oil.  I have 800TT on my RV-12 w/ 912ULS using Mobil 1Racing 4T...

There is nothing abnormal about seeing a climb temp of 230F - 245F for many people in the warmer months of the year. Outside air temps can play a big role here. Cold winter months vs hot summer months. Cowl airflow has another impact and each plane is different. I the southwest US during the spring and summer months you see 235F - 245F all the time in climb and then once you level out to cruise it goes down. Mobile One Racing 4T a full synthetic is okay to use if you use 91 oct. auto fuel (no lead). The Aero Shell Sport Plus 4 is a 10-40W semi synthetic and works well with either 100LL or 91 Oct. auto fuel. A full synthetic shouldn't be used if you always use 100LL. Either one works fine and has no issues with higher temps (230F - 250F) that you may have on your 912ULS. 

231F is starting in the yellow arc. The yellow arcs just mean "hey keep an eye on me so I don't go into the red arc settings." You can safely run in the yellow arc during climb. That said your temps should go down when the extra stress on the engine during climb is reduced in cruise which allows the temps to decrease back into a more normal area like around 210F - 225F depending on the aircraft airflow setup and outside air temps. Some aircraft are better at staying cool vs others. Hose routing for oil lines make a difference too. Too sharp a bend reduces the radius of the hose which slows oil flow which causes higher temps. As an example the Flight Design CTSW oil hose from the oil cooler to the oil pump makes a 180 degree bend and squeezes down on the I.D.of the hose. This reduces the oil flow and causes higher temps. I place a spring in the hose at the bend to keep the hose wide open and I can drop temps 15F - 20F.

The planes is a Bristell NG5 SLSA.

Thanks

Alvaro,

My 2016 Bristell NG5 (with 912iS) will run 235-238 F. on climb out in the summer months here in California, even at 80-85 KAIS, but then drops back to 210-220 in level flight.  In the cooler months I never see above 225 in a climb and 210 in level flight.  As Roger points out, it has not been a problem.  A friend’s 914 powered Bristell will run an oil temp of 245 F while climbing during the summer. 

I have noticed that recently Bristell started delivering their iS engine aircraft with the extra large oil radiator. I think they are using the radiator that is stock for the 915, Rotax refers to as “extra large”.  I know of one locally, and it runs 15 F. deg cooler when climbing. They have also changed the air intake on the front of the cowl to accommodate this.  I’m not aware that Bristell has made these changes on the ULS engine models, but the USA Bristell dealer does offer a modification to install the larger oil radiator, which requires modification to the lower cowl section.  

Sorry - crossed conversations