oil temp
 

Back on Fire Patrol here in B.C. as of last week, and have a concern: Rear oil temp was running about 30 degrees cool of red line with an OAT of 10 degrees C at 8500ASL- Way too high I thought, I don't recall seeing that last year. First course of action was to switch Vernatherms front to rear, to see if the problem manifests itself in the front engine, identifying the problem as a faulty valve. Well went out yesterday, and sure enough, the front engine temp is up about 230DegC, but the strange thing is the rear is STILL running about 230 as well. Any Suggestions? What SHOULD the oil temps be running at under those ambient conditions? Running 2300RPM at 19"MAP at 50 degrees rich of peak around 9000ASL
Thanks

Oh, it should be much cooler. I suggest you check the baffles, and change the oil. You may have some crud in the oil lines.

We actually just replaced all the engine hoses last month. Baffles are all in great shape. Oil change due tomorrow, but I'm skeptical that will make much difference. What are the chances the cooler itself is clogged? How often does that happen?
Robin

It's possible that in replacing the hoses, some fod got knocked loose and clogged things up. Did this start happening right after the hose change?

No, I vaguely remember the rear temp being high when I flew it back in April. Back then I thought it might be some FOD in the scoop, but I checked and found nothing. More recently, I initially thought it might be the cooler was clogged (happened in one of our 172s) but a local engine guy suggested a more likely scenario was the vernatherm. What are the chances it was a) the rear oil cooler, and we screwed something up with the vernatherm when we switched it causing the front engine to develop the symptoms, or b) it was BOTH the rear cooler AND the rear vernatherm. Flown it over 40 hours since fist posting this, and the temperatures front and rear are consistently close to 230 degF. Also, the temps both come up to about 200 VERY quickly after the start. Ambient temp on the ground has been about 75 deg F.