You are thinking just like I am, what's different? Here we go.

At first I thought it was the small baffle seal inboard of the cooler,=20= it=20 had flopped out and left a gaping hole. I thought for sure that was=20 it. I posted photos and descriptions on the ES Yahoo group. That= 's=20 been all sealed up with red silicone.

The jump in temps occurred in the middle of an oil change, the first ru= n=20 with regular oil, after the break-in oil was removed. I used the Phill= ips=20 Multigrade break-in oil. I am using Shell 15W-50 Multigrade oil now.

Oil pressure has remained constant at around 45 in cruise.

Nothing in the engine compartment or baffling has changed. I have= =20 made minor changes since the oil temp rise, but they were minor sealing of=20 holes, trimming of baffle seals to get a better fit.

Operation of the heater hasn't shown any changes either. My heat duct i= s on=20 the other side.

I haven't checked mag timing.

Here's the only "thing" that happened at the time the temperatures=20 jumped. I was invaded by birds nests in Huntsville. I had to lea= ve=20 my plane there for a week, waiting for my JPI to be repaired. I pulled= out=20 giant nests on both sides. My first thought was crud in the vanes of t= he=20 oil cooler. I landed in Memphis when I saw the jump in oil temps and=20 reinspected the cowl and the oil cooler. I blew some air through the v= anes=20 and it appeared to be fine. I inspected all the electrical and hoses f= or=20 any signs of chewing, nothing. I have since shined a light through the= =20 cooler, used mirrors, you name it to check for any dirt blocking air flow=20 through the cooler. Nothing. This has been my focus since the ju= mp=20 in oil temps, but I simply can't find anything to tie the birds nests to the= oil=20 temp rise.

So the birds nests must be a coincidence.

I'm going to change the oil this week, new filter, check the accuracy o= f=20 the oil temp probe, check the operation of the vernatherm. I may conta= ct=20 TCM and see about getting a new oil cooler, or at least a new vernatherm.

The more I think about this... the more it seems like a clogged,=20= or=20 partially clogged oil cooler. Almost like something is restricting the= =20 flow of oil, something that worked its way through the system at 30 hours an= d=20 blocked a major portion of the cooler. Since so many ES guys, and a co= uple=20 Legacy IO-550 guys have had high oil temps, it may be more about the engine=20= than=20 the engine installation. The search continues....

So do you consider my CHT's of 365 to 385 to be normal or ideal?

Thanks for all the help Scott,

Mike Easley

Colorado Springs

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