Does the coolant go in the radiator cap Isuzu trooper or in the odd shaped bottle to the right of it. how does that system work?

Answer 1

If it is marked coolant the funny bottle gets the coolant.

How it works:As the engine warms the coolant the pressure in the system increases as a normal result of warming.

The pressure is released by the radiator cap by bleeding excess coolant into the bottle.

As the engine cools the reverse happens but the valve works at much lower pressure (vacuum) going back into the system.

It also works this way to keep it topped up with no air in the actual cooling system.

You can see the valve that allows coolant back into the radiator in the centre of the cap id you take it off.