My RV7A engine is showing low engine oil temperature in a new Lycoming IO_360-M1B with AFS3500EE. 130F at cruse. The spec sheet for engine oil temperature says the engine left the factory heating to 179F. Spoke to Lycoming, they suspect the probe. They suggested removing the probe and placing it in a beaker with heated engine oil with a standard kitchen thermometer and comparing temperatures. I used a simple electric griddle for the heat source. I recorded temperatures rising to 200 on the kitchen thermometer and temperatures falling back down after turning off the heat. I used, used automotive 10w30 engine oil. Any difference I think would be small. Below is the data I collected.
I spoke to someone at AFS the other day on this issue, they said to check the grounding. The probe is grounded with safety wire to an engine bolt.
Assuming the probe is not faulty and needs calibration, I see an adjustment for oil temperature under the administrative section. The next question is how much? I think setting it for accurate temperatures at 180 would be best. Rising temperatures at 180 were off by 60F on the EFIS, falling temps at 180 were off by 44F. Just guessing...start with an adjustment of 44?
AFS Oil temperature sensor on EFIS 3500 vs. Kitchen thermometer in heated engine oil in degrees F.
Rising temperatures
EFIS/ Thermometer
85 122
88 130
94 140
103 150
110 160
115 170
120 180
124 190
131 200
137 205
141 208
Falling temperatures
143 200
140 190
136 180
132 170
127 160
122 150
117 140
110 130
103 120
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