Low Oil Temp

[Rolly9]

RV-9. Sensenich FP. Lyc O-320-D1A. I have a Vans Oil Temp Gauge. I have the oil cooler about 75% blocked by 1/2 cover over the inlet and the outlet is completely closed except for 1/4 inch hole. At P.A. 3K feet, OAT=40F, 2500 RPM, IAS=185. After about 3 minutes the Oil temp rises to 140 and then will suddenly drop to 110 and start climbiing again. But it never goes above 130??!! Oil pressure is 78. CHT is 280. .. Bad gauge? Bad thermister? Thx. Rolly

[BobTurner]

Sounds like the probe to me. The oil cannot "suddenly" drop 30 degrees.

[Roy Thoma]

Rolly,

Make sure your sensor has a good ground. It's not uncommon for a right angle oil filter adapter to cause a poor ground with resulting low readings. A hose clamp on the sensor securing a wire with a known good ground may solve your problem.

Regards,

[flyboy1963]

Originally Posted by BobTurner

Sounds like the probe to me. The oil cannot "suddenly" drop 30 degrees.

I am always trying to learn how these things work....could the drop not be from the vernatherm 'opening' and the flow surging into the cold oil cooler? ( or is it the reverse that happens, I don't have the flow diagram handy).
I know I was shocked to see how my oil pressure dropped -at idle - when I banked left onto base! ( and yes, I should be keeping my eyes outside instead, just caught it in my scan!)

[Walt]

I've personally seen the Van's OT gauge read 20d low as compared to an Electronics International gauge. I think its due to the adapter that the probe sits in because on the bench it "tests" good.