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Dave12

Well Known Member
Took wifey up tonight for her first flight in the 12 and noticed very erratic oil temp readings. OAT 22C and oil temps from 213 degrees to 247. These readings were not hopping all over the place, but in my opinion were changing quicker than the oil could heat or cool. 20 hours on the hobbs and this is the first time I have seen this behavior. Any thoughts?
 
Hey Dave - -

First things I would do ( and I think I did this myself ) Check crimp on wire end at sender. Also just take connection off and put it back on a couple times to be sure connections is good. If I recall, one of those helped me.

John Bender
 
Thanks John, first chance I have to remove the top cowling I will check that. Did you actually see these erratic numbers at some point?
 
Hey Dave - -

Yes. It seems I remember moving the connection at the sender around, and it seemed to make a difference. Can't remember if that was a connection I re-crimped or not. I had one that was an issue, maybe more. Those tiny wires are more difficult to crimp well. A good place to start anyway. Most of my issues happened during the first 100 hours, so seems logical to me.

John Bender
 
I had a simillar event. Except it was my oil pressure sender. Little gal came on and said "Check Oil Pressure, Check Oil pressure". I had 7 hours on the air frame. Then, it went back to normal. A few minutes later, "Check oil pressure, Check oil pressure."
Needless to say, I was looking for a place to land.
It was a loose wire to the sender. I could move the ring terminal under the nut. I put some loctite on the nut and tightened it up. No more issues.

Do secure your sender wires so they cannot flop around in the breeze under the cowling.
 
I'm having a similar problem

with the right CHT readings. Sometimes just a few degrees less than the left, sometimes moves up and down, and sometimes drops (for a few seconds) to ambient temp. Squeezing the "finger" that slides onto the sender helped for a while-- will check the whole thing carefully at the annual-- err, condition inspection" in a couple of weeks. That's not a crimp I made.

Wayne 120241
 
I removed the top cowling and and made sure the connection on the oil temp. probe is secure. Yesterday I flew about 150 miles and the temp did not vary as much as before. The oat was 70 degress F and the oil temp. was in and out of the yellow with power set at 5300 +or-. Would the rest of you guys agree that these little birds tend to run a little on the hot side? As per Lockwoods advice, my prop is pitched at 4900. Even with this pitch the 12 jumps off the ground. I am just wondering if some are accepting the oil temp running slightly in the yellow since the temps are acceptable to Rotax?
 
In my CTSW, I had the prop set for 5400 WOT in level flight. That improved my oil temps from the previous, coarser, prop setting but I was still running warmer than I wanted. About mid-summer I set it to 5550 WOT and it runs cooler. Now I can go from near SL to 10,000' just barely getting into the yellow on fairly warm days. This prop setting equates to about 5100 in an 80K climb.

So, my experience, and that of other CT owners, is that a little higher WOT RPM in level flight nets cooler oil temps. Try it. You can always put it back if you don't like it.

My Rotax experience is with the CT so I can't speak to the -12 installation but, yes, these engines can run a little warm on hot days. I would not be concerned about running in the mid yellow in a climb but if you are staying in the yellow in a 5200 RPM cruise I would be looking to change something. You say you are cruising at 5300 and that will give higher oil temp than 5200 but at 70 degrees that does seem a little warm.
 
HI oil temps.

If you read SI-912-016 R4 posted here:
http://legacy.rotax-owner.com/si_tb_...912-016-r4.pdf
Go to page 12 which is the last page of the Document and read
General engine operation requirements and operating tips, it would seem acceptable to operate the 912 up to 250F most of the operating period. So unless you are above this temp I would not be to worried about it. Check out Note 5 which recommends running the oil temp at 212F to ensure getting the water out of your oil.

rotax5017.jpg
 
190F

Finally figured out where the 190F recommendation came from. Attended the LSA Expo in Mt Vernon last week and attended a 912 seminar given by Brett from Leading Edge. He says the 190F is mentioned because at the measurement point, the oil temp is just coming out of the oil cooler and fixin' to get hotter, by 22 degrees. (I still like to see mine at 212 but thought that interesting). Also he mentioned that your oil temp should run approx 20 to 30 degrees above your CHT's. Checked mine on the way home...20 on the dot.
 
Jetguy, you are correct. My thought was that if Dave12 was running in the yellow at cruise on a relatively cool day that doesn't leave him much for a prolonged climb. Otherwise, operating up to 250 should be just fine.
 
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