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Extreme High Oil Temp on landing

J

jurik

I'm New Here
I flew my RV7 O-360 today at maximum RPM and reached 2800 at times. Throughout the flight the oil temp remained at around 215 deg F (101 deg C). I kept the speed and RPM up as I approached the field and once I turned down wind, I reduced the power significantly to decrease the speed to 100mph. The moment I did that, the oil temps went to 300 Def F (150 deg C) in seconds. I landed immediately and this temp was not maintained for more than 5 minutes.

I suppose that it was the sudden loss in speed causing this extreme temp increase or could also be the temp probe.

Have you experienced something like this before? DO you think I damaged the engine?
 
If you're breaking in a new engine, oil temp of 215 is pretty reasonable and normal.... But it doesn't jump from that to 300 by slowing in for landing.. that is way beyond normal and you should really check everything before further flight.

Start with the probe.. I do hope it's just a bad probe.. all other options are far worse.

As mentioned, if the probe is OK, I'd change that oil and would then pull the strainer from the back of the sump and check it during the oil change. I'd also check ignition timing and ensure it didn't get advanced (what do you have?)... Just a few thoughts.. but again, I'm really hoping it's just a bad probe..

Did you look at your CHTs? What did they look like?
 
The engine has done 40 hours al ready so its not a brake-in phase. Over this 40 hours, it has never done this. Not even during the first 10 hours.

The CHTs were absolutely normal.
 
I downloaded the flight recording and viewed it. Oil temps perfect right up to the middle of the base leg. Here I notice a 30 deg F increase over a 2 second period. Surely this cant be!!!

I also recall turning on my landing lights someware on base. Maybe this is the issue but I cant see how it is related in any way.
 
If it jumped 30 degrees, then came back down it doesn't sound like a probe problem.

Pure speculation here but if you were running the thing hard prior to this, then the engine was hot and the high flow of the oil pump kept the oil moving through the cooler/system. As soon as you pulled the throttle back, flow slowed dramatically and the heat couldn't be dissipated as fast, thus your spike. It came back down as slower flow of oil slowly dissipated the heat, along with airflow, etc.

Again, I have no idea what set up you have in your plane, just what it sounds like from a basic setup. Personally if this were my airplane, you only have 40 hours on the engine I would have someone pull a plug and look in the cylinder to see if you have any glazing.
 
Seen this before, check your firewall to engine ground. Saw oil temp go to 300 degrees when landing light switched on in the pattern. Discovered the ground cable disconnected from the engine! 99.999% sure this is your problem!
 
I had a similar issue and it was a ground problem, as others have mentioned. In my specific case, I had grounded the engine to a different location on the firewall than the 'battery/alternator" firewall ground. Moving the engine ground to this location fixed the problem.
Bob Cowan
100+ hours on N743RV
 
This is a good thread for many reasons....

...and I had a similar experience in my Air Tractor, except that the fuel gauges went to half tanks when I turned the nav lights on! Not wanting to run out of fuel, I turned them off:D

....but seriously, anytime you see an instant change in a gauge when you take an action, like turning something on, or off, suspect circuitry...usually a not-so-good ground. In my case, I added a ground strap from the upper instrument panel to the airplane frame.

Best,
 
I simulated it yesterday and it is definitely the landing light causing the error on the reading. It only made a 2 deg difference when it was cold but gave a 60 deg error when the oil temp reached 170 deg F.

Thanx for all the responses. I will now go and work on the grounding and see what I find.
 
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