[quote]But this doesnt explain why the engine heats up so much more slowly.[/quote]

Actually, it does.  It'll heat up more slowly, because the volume of water passing through the system is greater without the thermostat restricting it.  Less water volume to soak up the heat allows the water that is in contact with the hottest part of the engine to heat up faster as it's in proximity with the hot parts longer.

[quote]This would explain how an engine would heat up more quickly. I was saying the former, not the later in the statement you were reffering to.[/quote]

Not that it would heat up more quickly, but that it would continue to heat up past a 'safe' point.

[quote]I'm not saying no heat is being absorbed by the coolant. I'm just saying the amount of heat being absorbed is very little in comparison to having a thermostat in there allowing the vehicle to warm up.[/quote]

The heat absorbtion rate of water is a constant, it's just being spread over a larger volume, so initial warm up is slower without a thermostat.

[quote]The radiator can do it's job just fine (even without a thermostat) until it starts to heat up.Then the radiator becomes even less capable of dissipating what heat the coolant brings its way.[/quote]

The heat dissipatory rate of the radiator is also constant (given constant ambient air temperature and flow of air over the fins of the radiator).

[quote]Now technically this is a closed system.[/quote]

It's closed in relation to the coolant itself, not the outside forces acting upon it.  No new water is added or removed.

[quote]And I didnt mean faster as in speed, but faster as in the amount of coolant being moved: volume.[/quote]

Yes, I understood.  Where the coolant volume is constant, the velocity or speed of the coolant as it passes through the system is directly related to the volume.

[quote]If the volume of coolant being cooled is greater than the volume of coolant being heated by enough to make up for the difference in the temperature changes of the two, then the temperature goes down.[/quote]

Correct

[quote]Without a thermostat the coolant is rapidly flowing into the large volume radiator and then rapidly back into the lower volume coolant passages (only those around the cylinders, cause thats where the heat is generated). This causes an unbalance on the side of cooling.[/quote]

Only with relation to the length of time it takes for the full volume of the coolant to be heated.

[quote]Thus, the water is not absorbing enough heat from the engine in comparison to how rapidly it is being cooled.[/quote]

See previous comment.

[quote]If the thermostat is there to restrict it then the volume in the combustion chambers becomes greater than the volume being cooled.[/quote]

I wouldn't call it greater, just not 'being replaced' as quickly with cooler water from the radiator.

[quote]And normally a closed system such as this wouldn't allow such an event to take place. But the fact that the system has a radiator to disipate the heat is what allows the system to act as if it werent a closed system at all. So you cant really treat it like a closed system when looking at it from the laws of thermodynamics point of view.[/quote]

As I mentioned, it's closed in the sense that no water is being added or removed from the system.

[quote]Every time the water leaves the radiator its like fresh water is coming in, just like an open loop system.  So you cant make the comparison that way. [/quote]

Only if the dissipatory capacity of the radiator is equal too or in excess of the heat being generated by the motor.

[quote]If it were a completely closed system then I would agree 100% with you. In terms of physical characterics of the components themselves it is indeed a closed system. But the out side interaction through the radiator means it's not a true closed system. A true closed system does not involve the interaction of anything not within it's system. The air flowing through the radiator means the system is acually open.[/quote]

I see your point and unfortunately, in the physical world, there is no such thing as a completely closed system.  So, it's not unreasonable for you to conclude my use of the term is over stating the reality of the nature of this system.  Although, it is commonly used to describe 'certain characteristics' of a physical system and that was the context I was using.

[quote]Think of it like a computer (for a car). In closed loop the computer relies only on signals from its sensors within the engine and nothing else (such as coolant temp). Switch it to open loop mode and now it relies on signals from variables such as air flow and oxygen content of the exhaust (sensor outside of the engine). It's still only using it's sensors which are wired into the closed system but those sensors are now monitoring parameters outside the engine so it is no longer considered closed loop, it's now open loop.[/quote]

I guess it depends on how much of the 'system' you consider part of the engine.

[quote]When the thermostat is closed it's a closed loop system. Once that thermostat opens (or is removed) it's no longer a closed loop. It's an open loop system.[/quote]

Except for the fact that even when the thermostat is closed, it is still allowing some volume of water pass through the bypass holes just severly restricted.

Ultimately, the system is designed to achieve a balance between the cooling capacity of the radiator, the volume of coolant and the operating temperature of the motor at the maximum (practical) temperature efficiency of the motor within the designed operating parameters.

The key here is, as you originally stated, the volume and flow rate must be matched to the dissipatory capacity of the system or you'll get hosed.

So, in the end, ultimately you were right.  You just came to the conclusion with a few minor mis-conceptions.

This has been one of the most fun conversations I've ever had online! ;)