I asked the same thing about my Seneca III and I was put in touch with David McKenna by Steve Ells from Piper Flyers. Here is what David said:
James,
Here you go. Pics of the factory Oil Cooler Restrictor Plate for our Cont. TSIO360 oil coolers.
Engine experts I have listened to at AOPA events, as well as on-line articles, tell you that oil temp must reach 180F to boil the moisture off. In our case, we never achieved temp until I added the second ‘home made’ Restrictor Plate and kept both on year round, adding the tape to the third section from Sept.- June.
The plate measures 4.25” x 2.5” and 2.5” on the high side, .75” on the low side. There are screws already in place to fasten…very easy to make and secure.
David
I have purchased my PA-34 5 months ago and dealing with growing pains. I do not have winter plates in the plane and was going to try to manufacture them. Until then I am putting aluminum tape on the cooler to get by in MN weather.
He also gave me pics of them if you want send me your email and will forward them to you.
David has been a wealth of knowledge for Seneca III’s.
