What do aircraft owners need to know about oil coolers? The folks at Pacific Oil Cooler Service Inc. share a lot of information on the company’s website, including “An Inside Look at Oil Coolers,” “Common Oil Cooler Woes,” and “How to Spot a Bogus Oil Cooler.”
The latest is a simple primer on how to describe your oil cooler. They share it with us:
Have a Continental engine with a congealing cooler? When looking at the cooler, you will notice all of the oil pass rows passing under the crossbar are even and equal. If the cooler is off the aircraft, looking down inside is a solid bar.
Think you might have a non-congealing cooler? When looking at the cooler, 
you will notice that the middle oil pass is larger than the others. When looking down inside the cooler when it is off the aircraft, the divider bar will have a small hole, which allows the constant flow of warm oil through the cooler.
7th Stud Modification: If your TCM engine had the 7th cylinder hold-down stud modified, you will need to order a cooler that has been modified to accommodate this extra stud. There will be two notches in the mounting base — one cut out on the side and another on the top or bottom.
The Non-7th Stud Cooler only has one notch on the top or bottom and no notches on the sides.
The folks at Pacific Oil Cooler Service, Inc. say they have solved the problem with 7th-stud or Non-7th stud by offering new universal coolers that fit both applications.
Where is the Vernatherm?
On a Continental engine, if you have a non-congealing oil cooler, the vernatherm is in the adaptor plate or just below and behind the cooler. If you have a congealing oil cooler, the vernatherm is mounted in the accessory case. On Lycoming engines, if you have an oil filter, they should be in the same location with the vernatherm mounted on the filter adapter. Check Lycoming Service Instructions.
Important questions to remember about Lycoming hose-mountedcoolers: What is the width and what is height? Have a rear mounted cooler? Remember, to order gasket kits when ordering this cooler, company officials say.
For more information: 909-593-8400 or OilCoolers.com
