Coolant is an important regulator of engine temperatures. Coolant is a mixture of glycol and water. The chemical solution is able to withstand temperatures that would boil pure water, cooling an engine when its running; yet it also resists freezing, remaining a liquid when the engine is off overnight in severely freezing weather. You can purchase automotive coolant at any auto parts shop and most general retailers. Replacing the coolant in a 2005 Mini Cooper is a simple process. Check your Mini's coolant levels regularly, and add when necessary.
Park the Mini Cooper on a level surface and turn off the engine. Pull the hood latch inside the cabin, then get out an open the Mini Cooper's bonnet. Let the engine cool before continuing.
Loosen the coolant tank's cap slightly. The coolant tank is located behind the radiator. Do not remove the cap, just loosen it so excess pressure can escape. Wait a couple of minutes, then remove the cap completely.
Check the coolant level by seeing where the liquid fills the tank. If the liquid is below the MIN line, you'll need to add coolant.
Add coolant to the coolant tank until the coolant level reaches the MAX line. Do not go fill the tank with coolant past the MAX line.
Place the cap back onto the coolant tank and tighten it firmly. Close the bonnet of the vehicle.
Do not add coolant when the engine is hot, as escaping coolant can cause burns.