Quote Originally Posted by Greg Amy View Post
Bob, a couple of points.

- First, "coolant", in most common-usage of the word, refers to the water-based portion of the engine cooling systems. There's no intent here to apply this to anything else.

- Second, the intent of this rule, as I read it, is to ensure that open, blow-off systems, such as what's on most 'Merican cars, have tanks of sufficient size to capture all coolant that may bleed when the engine gets hot. Volkswagens do not have a "catch tank" per se; the V-dub (and Audi and presumably Porsche) system is a fully-enclosed, flow-through system. The plastic tank you see is nothing more than a convenient reservoir/expansion tank, and is actually part of the cooling flow circuit.

I see no application of this rule to either lubrication oils nor to flow-through systems such as the VW/Audi example. At worst there may need to be a simple edit to the proposed rule that this would not apply to fully-enclosed, non-blow-off, flow-through systems.

GA
Greg, you can add certain years of BMW's to that list too:



This the radiator assembly that's in my car now. If I went with an aftermarket aluminum unit, then I could see adding an additional tank, but on the stock system there's no place to add anything, not even a hole in the radiator neck.

Quote Originally Posted by shwah View Post
Huh. Surprising that the 924 has a non-VW style system, when it was conceived and designed as a VW originally. Learn something new every day.
Going back 24 years ago when my dad and I were rebuiling the motor to my Audi 100, we were told by some parts guy that the 924 motor was sourced from Audi, not VW, and so it makes sense that they'd use an Audi type expansion bottle.