Hmmm,,, okay here goes my 2 cents: The “spring loaded” cap is referring to a very small, very light pressure spring that just barely keeps the “coolant recovery check valve” closed. (that is, the little circular valve on the bottom, in the center of the pressure-sealing gasket.) -not the large pressure-regulating spring.
That little check valve (fluid equivalent of a diode in electricity) is sealed tight under normal operating pressures. When everything cools down, -especially overnight, the negative pressure in the system then draws coolant back out of the bottle, into the radiator by slightly opening that little check valve.
I’ve used both types on my old Astro Van, and I can say for sure that the spring-loaded cap ensures that the cooling system comes up to operating pressure much faster. Upon inspecting both types for my ’99 Bonneville, I decided that the spring loaded was probably better.
So, why did they go to that design?? -Don’t really know, but I’m wondering if maybe they figure it offers a little more insurance of keeping air out of the system ?? Anybody else have any ideas ??
Oh yeah, and about the discrepancy in the torque values: I used the higher settings on mine, and now wish I hadn't. From my experience, the higher setting distorts the plastic enough to cause the inner edges of the tuned air runner tubes to distort slightly, and not seal properly against the inner gasket. -can't see that it will cause any harm, but it does cause a loss of seal on the tuned runners inside. Everthing is still vacuum sealed by the outer perimeter gasket.
A couple of days after I had mine all back together, I noticed a slip of paper that had come with the gaskets, and said to use the lower settings. Oh well,, all is still fine.