Oil Temp in Red

[Brett Kallish]

Hi folks, I was flying my new to me 1967 Mooney C yesterday and after about 30 minutes I saw that my oil temp was close to the red mark so I turned back to the airport and tried a few things to cool the oil down. The temp went above the red before I landed. Shut her down and went home. Today I went back to the airport and checked the oil level and it was about 6 quarts which is the same as yesterday, then I turned on the Master and the oil temp gauge, which was at the left or 0 degrees went right up to 160 degrees without the engine on and it was about 50 degrees outside. In about 5 minutes it went up to about 180 then wobbled a little bit and held there. It seems to me that it was not the oil heating up to cause this problem so I am going to start looking at the wiring to see if there is a short or something is loose. Do you folks have any thoughts on where to look and would you still fly without a working oil temp gauge until it is fixed.

Brett

 

[Hank]

Check the oil filter safety wire. Mine wraps around the oil temp sensor; if I'm not careful while wrapping it there (a loop at the beginning to anchor before going down to the filter), the wire will come loose and ground out the Oil Temp and peg the gauge.

[Bob_Belville]

CAR part 3: 3.655 lists an oil temperature indicator as required basic equipment. I suppose the plane is not airworthy if it is inop. But I am just an old PP.

[Brett Kallish]

Hank, thanks for the suggestion, I will try it tomorrow.

Bob, I was not planning to fly it and I am an old PP, too.

Brett

[ArtVandelay]

Do you have an engine monitor?

[Yetti]

The gauges and such will be pegged high if they short to ground.

[Guest]

After confirming the electrical wiring and connector to the temperature probe, you could remove the probe from the oil filter adapter, re connect the wiring then drop the probe in boiling water to see what the gauge reads. It should be around 212 F.

Clarence

[Brandontwalker]

After confirming the electrical wiring and connector to the temperature probe, you could remove the probe from the oil filter adapter, re connect the wiring then drop the probe in boiling water to see what the gauge reads. It should be around 212 F.

Clarence

I did a similar experiment not too long ago when questioning the accuracy of my gauge. I used a fry daddy so I could adjust the temperature. One thing to note is that you will need to connect a ground wire from the airplane to the probe base. I used some cheap wire I had laying around for the ground and to temporarily extend the existing wire beyond the cowl.

Best of luck.

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[N201MKTurbo]

I believe the C has an AN temperature probe and doesn't need a ground. The J has an automotive temperature sensor that does need a ground.

[Brandontwalker]

I believe the C has an AN temperature probe and doesn't need a ground. The J has an automotive temperature sensor that does need a ground.

Good to know. That would have made the job much easier.

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[cliffy]

Unfortunately it needs to be fixed before you fly again; Required equipment. Check and clean each connection, Look for corrosion at any crimp connectors, Open and close any "knife" connectors, my guess is a bad connection. Test the system in hot water as noted. Your A&P may have some more ideas also.

Although chances would be slim, if you were caught flying it they could file at least  4 violations on you

flying without required equipment

flying with inoperative equipment

91.13  Careless and reckless operation

91.3 Pilots always responsible  

It's just not worth the risk

Lots of new to me airplanes develope a problem or 2 initially. Learn from it, and move on to enjoy your airplane. 

[bonal]

My question is as long as you have your functional Garwin cluster and your stock EGT can you install a non certified monitor as long as you keep your original operational gauges since there are lots available for experimental at a much lower cost.

[rbridges]

That's kinda what most people do. My ubg16 runs around 1500 new but isn't primary. Can you get an experimental engine monitor for much less?

[Brett Kallish]

Well folks it turns out that it was the plug in back of the gauge. I couldn't figure it out myself so I took it to the local mechanic and he fixed it. Went flying today and everything went well. Thank all of you for all your suggestions. 

Brett

[FloridaMan]

I was going to suggest that you take your thumb and firmly press against the gauge, but it looks like your mechanic figured it out. I had the same issue prior to having my engine monitor installed. Oil pressure was fine (you should see it drop if temperature was high) and I verified the temperature at the filter with a thermometer upon landing. 

I discovered it was the gauge when I noticed that the gauge did not drop to zero when I turned off the master, which to me indicated that the coil was still energized (bad ground). 

[Guitarmaster]

On December 12, 2015 at 7:27 PM, cliffy said:

 

Lots of new to me airplanes develope a problem or 2 initially. Learn from it, and move on to enjoy your airplane. 

AMEN to that!!  ^^^