Winter Oil Temps

[bakerde36]

Hi all,
I was wondering how you all keep your winter oil temps above 180 degrees. I have blocked of my bottom oil cooler but it is a guess how much to block, the other day I obviously block off too much as my oil temp got to around 230 before I could get back down. Is there a rule of thumb or a mechanical way of controlling the opening?
I do have the bottom oil cooler. Thanks Densil

[XenosN42]

The winter oil temps on my AeroVee/OneX are usually around 160F with OAT in the mid to high 30s. Rarely have I seen temps in the 180s.

I remove my oil cooler in late fall and reinstall it late spring.

[GraemeSmith]

I made a sliding baffle to partially close off the vent "smile". A little experimenting and i know the ampunt to slide shut for different temps.

[mike.smith]

On really cold days 140 is all I get with everything blocked off. Average is 160 on cold days. Oil pressure still remains about 49-50 psi. Never had any issues flying through 5 winters. 25 deg OAT is about my lower limit in my VW Sonex. Summer time my highest oil temps are about 190, with 180 being more average.

[mike.smith]

22 deg on the ground and the teens in the air today (colder than I usually fly). 140 deg oil temps in flight. 49-50 psi OP.

[Direct C51]

22 deg on the ground and the teens in the air today (colder than I usually fly). 140 deg oil temps in flight. 49-50 psi OP.

Mike, your oil pressure seems to be within limits with your cool oil, but have you considered that your oil is too cool to evaporate any moisture from the crankcase? I would be very concerned if my oil temperature never reached 200 degrees. You might have significant condensed water vapor that is not being evaporated. Additionally, motor oil is a much better lubricant at 200 degrees than it is as 140 degrees. It is just my opinion, but I would not continue flying your airplane with such low oil temperatures. It is customary, and easy, to block off a portion of your oil cooler to allow the oil temperature to stabilize at a normal operating range. If you have everything blocked off and it is still only 140 degrees, perhaps your oil temp sender is bad, or you need to completely remove the oil cooler as some Sonex guys do.

Does Sonex publish a normal oil temperature range for the Aerovee? Min ? Max?

[GraemeSmith]

I'm flying in the same conditions (and 55NM away) as Mike. It's tough to get the oil temp up and stay up. If I remember correctly - Mike has his "smile" on the front of the cowl closed off.

Me - I've made a variable closure for my smile. If I close it off completely - them my bottom mounted oil cooler gets too hot. Leave it open a tad and I can get the oil to more or less stay in the range - on a climb - no problem. On a descent - the oil gets too cool - so I have to resort to powered descents to keep things warm. I do wonder if my front mounted temp sender is a bit too much in the cold air stream and giving a false low. Might make a small baffle to shield it from direct airflow.

I'm getting good pressure - but if I see it start to pulse high/correct - I know the oil is cool and thick in the pressure regulator and do whatever it takes to warm it up again.

[mike.smith]

22 deg on the ground and the teens in the air today (colder than I usually fly). 140 deg oil temps in flight. 49-50 psi OP.

Mike, your oil pressure seems to be within limits with your cool oil, but have you considered that your oil is too cool to evaporate any moisture from the crankcase? I would be very concerned if my oil temperature never reached 200 degrees. You might have significant condensed water vapor that is not being evaporated. Additionally, motor oil is a much better lubricant at 200 degrees than it is as 140 degrees. It is just my opinion, but I would not continue flying your airplane with such low oil temperatures. It is customary, and easy, to block off a portion of your oil cooler to allow the oil temperature to stabilize at a normal operating range. If you have everything blocked off and it is still only 140 degrees, perhaps your oil temp sender is bad, or you need to completely remove the oil cooler as some Sonex guys do.

Does Sonex publish a normal oil temperature range for the Aerovee? Min ? Max?

160F is the published minimum (80F for takeoff, but I look for 100F). I have every bit of my oil cooler blocked off (top mounted) and the bottom "smily" fully closed off in the winter. I can't remove the oil cooler or the engine would cook in minutes in the warm weather. I've never seen any sign or indication of water in my oil. Not ever. I do oil analysis at every oil change (25 hrs) and I bore scope the cylinders and valves at every annual. Again, no signs of abnormal wear, moisture or rust; in 500 hours and 6 years. So as long as nothing presents itself I'll just keep on keeping on. :-) When the weather gets warmer the temps will naturally come up.