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AirbusPilot

Well Known Member
Hi Folks,

I just changed oil and filter for the first time to my Lycoming IO-360-M1B at 10 hours. But oil tempeture has lowered from 180 to 150 degrees. CHT, EGT and outside tempetures are about the same so why the oil tempeture has lowered.

Anyone with the same problem???
 
I have the same engine but did not experince such drastic reduction in oil temp. You are still using the same type oil right?
 
Maybe it is a complete coincidence that this change occurred the same time as you changed the oil. I had one of my CHT probes start reading low, and the cause turned out to be high resistance at a connection. I cleaned and reseated the connector, and that CHT indication came back in line with the others.

How is your oil temperature probe grounded? I'd look for a bad ground there. I'd also reseat any connections in the ground or power wires for the oil temp probe.

As a final check, you could remove the oil temperature probe and put in a pot of boiling water to confirm it is reading correctly.
 
run in

if you are breaking in a new engine,,, did you change the kind/ weight of oil,,, or anything else??
 
Fernando,
I had the same problem with a Dynon oil temp probe. One day, it stopped reading above 150, Dynon sent a new probe and everything was normal again.
I'm betting it's the probe!
Regards,
 
Dynon oil probe failed

I messure temp with two digital termometter and two infrared termommeter and Dynon probe read accurate tempeture below 150 F but do not goes up from there. I am absolutely happy with dynon avionics but aparently they use cheap probes.
 
I have the same issue here with the dynon oil temp sender. It won't read anything higher then 150F.
 
Kevin Horton said:
As a final check, you could remove the oil temperature probe and put in a pot of boiling water to confirm it is reading correctly.
Click to expand...

How do you physically do this? Do you patch in some long wires between the temp probe and the aircraft? And how do you handle the ground? Also, what is the best (i.e. the safest) way to boil the water? Thanks.

-John
 
boomer said:
How do you physically do this? Do you patch in some long wires between the temp probe and the aircraft? And how do you handle the ground? Also, what is the best (i.e. the safest) way to boil the water? Thanks.

-John
Click to expand...

Hey John, I paid $12 at Target for a small plastic water boiling pot. It's electric, so you'll need an outlet and extension cord. But, if you know your airfield elevation and pressure, you can easily figure out what temperature your water boils.

I tested my oil temp probe this way...my calculations for that day said water should boil at 207 degrees (F)...my EFIS showed within 1 degree of that, so I was happy that the probes were good.

Edit: I may not have answered your question. But this may help...I simply sat the electric pot next to the engine, close enough to dip the probes in. No lengthening of probe wires required.
 
boomer said:
How do you physically do this? Do you patch in some long wires between the temp probe and the aircraft? And how do you handle the ground? Also, what is the best (i.e. the safest) way to boil the water?
Click to expand...
You can find a description and picture of how I did it here. I did the test before I secured the oil temp probe wiring, and the wire was long enough to get in a steel coffee can, which I heated with a propane torch. Ground was not an issue with my EIS 4000. It worked properly without the probe being grounded. I'd use a pair of aligator clamps and a piece of wire to do the grounding if I had a probe that required a ground.
 
I just replaced my Dynon oil temp probe AGAIN! Noticed it during aerobatic practice when the temp always climbs to 200 degrees. Looked and saw only around 150. Dynon sent new probe. Installed, normal temps again.
 
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