Oil Temp IO360 RV-7A

[Pat Stewart]

Thanks everyone, thanks for the picture Dan. Alton all is well here, how is Dothan, we really miss all our Dothan friends and the weekly visit to Hunts. Say hello to everyone for us.

Pat

[Pat Stewart]

Looks like the sender is in the correct location. I removed the tape from the oil cooler and flew it again. The OAT was 94f climbed to 3500 with an OAT of 84f. Oil temp climbed to 157f and that was it. I think this is starting to look link a bad Dynon oil temp sender but would still appreciate feedback.

[DanH]

Originally Posted by Pat Stewart

Looks like the sender is in the correct location..

Ok, so unscrew the sender and dip it in boiling water.

[Pat Stewart]

Thanks Dan I will do that next. It is interesting that the oil temp read the same with the oil cooler 25% taped up as it did when tape was removed.

[lr172]

Originally Posted by Pat Stewart

Thanks Dan I will do that next. It is interesting that the oil temp read the same with the oil cooler 25% taped up as it did when tape was removed.

It is not uncommon for a sender to fail/wear at the extended end of the range. They use a bi-metallic spring that can lose it's temper. The fact that you are a few degrees off at ambient would make me suspect the sender. Hot water and a candy thermometer will confirm.

Larry

[Taildrgr]

Here?s a post from the Dynon forum:

Title: Re: Oil Temp Sensor?
Post by Dynon Support on Apr 6th, 2009 at 6:11pm
________________________________________
A simple bad ground on the sensor would make it read low. The temp goes up as the resistance goes down, so extra resistance with a bad ground would lower the temp.

A bad ground between the sensor ground and the EMS (ie between the engine and the battery) can make the sensor read high, since this causes a voltage drop across the wire, which is the same as a lower resistance.

With a voltage drop, the sensor gets much more inaccurate at higher temps. It only takes a few mV at 220F to cause a 10-20 degree error.

The easiest way to test for this is to turn off your alternator. This will stop the ground current and will show you if it's causing an issue.

We don't publish the full characterizations of the sensors - we consider that proprietary data - but here are a few points that should help you along:

49.4F 1540 Ohms
103.5F 390 Ohms
150F 155 Ohms
220F 45 Ohms
280F 22.1 Ohms

[Pat Stewart]

Looks like it's the sensor. With the old sensor I had a 10 degree spread between the oil temp reading and the CHT readings while cold in the hangar. Installed the new sensor last night and both read the same. Just need the weather to clear so I can fly it and see what the real reading is. I talked to the oil sample folks who just finished an oil sample, they said there is no indication in the sample that the oil got too hot. Also CHT readings were always fine so I am pretty sure all is well. More to come after I fly it.

[Pat Stewart]

Weather cleared and we had a chance to fly this evening, everything normal, oil temps exactly as we expected. Thanks for all the input.

Pat