Oil temp probes

Has anybody had problems with GRT oil temp probes?
On the way to Sun n Fun shortly after takeoff, I noticed my oil temp on my GRT EIS was showing 59 degree's.
After consulting with the GRT gang they said that 59 indicated an open circuit on the temp probe, and 303 degrees indicated a short to ground.
They had a spare probe with them, so I installed it and guess what, the EIS now reads ambient temp (75 degree's). Problem solved right?
Wrong! Soon after takeoff from Lakeland, I get the flashing red light and acknowledge 303 degree's oil temp. It stays that way all the way to within a half an hour from home(Cincinnati), then reads normal (180 degree's).
Since I had some other spurious indications on the EIS the GRT folks sent me another box. Flew the plane before swapping boxes, oil temp normal for about 10 minutes then right to 303 degree's. Okay come back, swap boxes, uh oh 303 on the new box. Now I start digging into the harnesses to look for chafed or cut wires. Everything looks good, so time to check the new probe from Sun n Fun. Disconnect the probe, 59 degree's which means open circuit.
Connect the probe, 303 degree's which means shorted to ground.
OHM meter across the probe reads no resistance.
So it looks to me like another probe failure, or am I missing something.
I'll call GRT in the morning, I really hope it's the probe, but 2 failures lead me to think somethings causing me to eat up probes.

Wow, it is nice to know I'm not the only one.
I'm doing this dance with the GRT probes (both oil temp and carb temp). My clear test is that I can connect an ohm meter directly to the sensor leads and slightly wiggle the wires where they enter the sensor. The resistance is all over the scale from fully shorted to fully open. GRT has sent replacements that have the same behavior. Totally useless on a vibrating engine. They are in the process of sending me a third set, we'll see.

As an update the new probe (#2) from GRT has worked flawlessly now for 3 months.
On the other hand my hangar mate Sam Marlow experienced the same bad probe on his RV10 last month, GRT sent a new one and it's fine now too.

Thanks for the update. I was wondering.
I'm looking forward to my third set of probes...

scard said:

My clear test is that I can connect an ohm meter directly to the sensor leads and slightly wiggle the wires where they enter the sensor. The resistance is all over the scale from fully shorted to fully open.

Click to expand...

You might try putting a blob of "Shoe Goo" where the wires go into the sensor, build it up at the sender, and taper it up and out the wires for a half inch or so.

Also, make sure you dont have a bunch of wire flopping around there. Bring the wire back to a solid support within as short (3 or 4") of a distance as is practical.

The idea is to prevent/minimize the flexing at the sensor.

Good luck.

59 degrees

On my way to CLW to pickup my grandson I had the oil temp drop to 59the degrees....
Nothing new in this world that 10 min @ VAF won't set you off in a proper vector
Thanks.
Call into GRT to order new probe & developing a plan to confirm circuit continuity.
N358JR