I am confident in saying that most of us have had some sort of coolant leak. These trucks have a pressurized coolant system that can drive us nuts when you are repairing them, seems like when you make a repair the next weakest link is sure to spring a leak. I understand that it is best to find all the problems at once but for us doing our own repairs a these systems can leave us chasing leaks. So is there an advantage to these type of systems?

 

All cars have a pressurized cooling system, if you didnt the engine would overheat within 15 min of driving.
Pressurizing the cooling system increases the boiling point of the coolant, and considering that a engine runs at 200*F that only leaves you 12 degrees to play with, so the first time you stop in traffic, turn on the a/c or climb a hill you will be pulling over.
Granted engine coolant naturally has a higher boiling point than plain water but it will still boil quick if not under pressure.
If you live on a mountain then the less the air pressure the lower the boiling point still.
So remember grade school, at sea level water boils at 212*F.
The higher you go the faster it boils.
If you have a small leak and need to get it home you can leave the radiator cap off and drive at slow speeds and short distance in a emergency only though.

Does that help?

 

I think he means we have a pressurizsed overflow tank. Some vehicles have non pressurized reservoirs.