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Oil Coolers, '101' - Page 2

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Step Number One; Identify the type of oil cooler that's currently bolted to your TCM engine (don't rely on parts-manual information). You can try looking for a part number on the oil cooler - but chances are that you won't be able to find one (or if you do see a part number, you may not be able to read it).

If there's no part number visible, here's how to put a positive I.D. on the unit: First determine weather it's an 8-bolt, or a 12-bolt oil cooler:

12-Bolt Continental oil coolers have 5 mounting bolts along each side, vertically - and 3 bolts along the top and bottom sides (yes, it does add up to twelve). 8-Bolt units have 3 bolts along each side.

If it turns out that you've got an 8-Bolt oil cooler, then you can stop right here because that's about all you need to know. 12-Bolt oil coolers (on the other hand) are the ones that require you to gather more information to ensure that you will get the correct replacement unit (read on):

12-Bolt Oil Cooler I.D. Checklist:

Determine weather you've got a Congealing, or a Non-Congealing oil cooler. The easiest way to determine which type you've got, without unbolting the cooler from the engine, is to ascertain the thickness of the cooler's base-plate (this is the part that's welded to the cooler, not to be confused with the oil cooler adaptor plate located between the oil cooler and the engine). Here's the key: Congealing oil coolers have a base plate thickness of roughly 1/4". Non-Congealing oil coolers have a base plate thickness of about 3/4". Another clue has to do with the location of the Vernatherm (a fancy word for the thermostatic oil control valve). Non-Congealing oil coolers use an adaptor plate that's got a Vernatherm threaded into it. If there's no Vernatherm screwed into your oil cooler's adaptor plate - and there should also be no place to screw one in - then it (the Vernatherm) is located elsewhere on the engine (and you've definitely got a Congealing type of oil cooler).


Engine oil thickens at cold temperatures, this thickening is commonly referred to as congealing. Even though it may be bolted right up to a nice, toasty-warm engine, it's possible for a Congealing type oil cooler to remain cold enough to cause the engine oil inside it to remain cold and thick (congealed). Only when your engine's oil temperature gets up to about 160 - 180F does the vernatherm direct any oil to the oil cooler. The two quarts of congealed oil inside the oil cooler will be in no great hurry to go anywhere, despite the sudden request for cooling place by the vernatherm. Eventually the warmer oil will have its way and oil flow through the cooler will occur, but this can take considerable time.

To avoid this situation, Non-Congealing oil coolers were designed to have a small - but continuous - amount of engine oil flowing through them at all times - even when the vernatherm is in full oil cooler by-pass mode at low oil temps. Non-Congealing oil coolers feature what is (non-technically) referred to as a "Wee-Wee Hole" (as in the picture above, right). This "Wee-Wee Hole" is a passageway running through the center of the oil cooler, through which a constant supply warm engine oil is pumped. This keeps the oil cooler - and the roughly two quarts of oil it contains, at (or near) the temperature of the engine. This way, engine oil can easily flow through the oil cooler the very instant that its flow is directed there via the vernatherm.

At this point, you've got enough information to determine weather your TCM engine has an 8-Bolt oil cooler, or a 12-Bolt oil cooler. If yours is a 12-Bolt cooler, then you will have also determined if it is of the Congealing, or the Non-Congealing variety. The next question is:

Do You Need A 7th Stud, Or A Non-7th Stud Oil Cooler?

TCM's 7th cylinder hold-down stud modification affects both types of 12-Bolt oil coolers; Congealing, and Non-Congealing (in the above examples, a Congealing type oil cooler is shown). All 12-Bolt oil coolers have a single half-moon cut-out in the base plate's bottom edge. If there's a second such cut-out along one of the vertical edges of the cooler's base plate, then you've got a 7th Stud type of oil cooler. This added notch in the cooler - along with a re-located oil cooler attachment bolt-hole, provides clearance for the added 7th cylinder hold-down stud. 7th Stud type coolers also require the appropriate 7th Stud adaptor plate and gasket.


12-Bolt, Non-Congealing Continental oil coolers are available in three different lengths: 10", 11", and 11.5" - as measured from the gasket surface of the cooler's base plate, to the furthest reaching part of the tank on the opposite end of the oil cooler.

That about covers everything you will need to know so that you will have the best possible chance of getting the correct replacement oil cooler for your Continental engine.


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Pacific  Oil  Cooler Service, Inc.
1677 Curtiss Court, La Verne, CA 91750

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