G6 Coolant Flow Diagram

1. Radiator
2. Cooling Fan
3. Water Pump
4. Thermostat
5. Coolant Reservoir

Coolant capacity:
With Heater: 7.9 Quarts
Without Heater: 7.3 Quarts

Thermostat Temp:
180-190 Deg F

Water Pump

Shown above is the water pump for the 87-88 B2600. This should be the same water pump as on the Mitsubishi Montero 4 cylinder from 1983 through 1989 and Chrysler Conquest Turbo 2.6L from 1984 through 11/1986.

Lucas part number is: WP4354.

Overheating Issues

• Coolant level.
  This one is obvious not enough coolant engine overheats. Never try to check the coolant level with the engine warm, when the engine starts to warm up the coolant system pressurises. Opening the cap will cause a sort of explosion and WILL SEVERLY BURN YOU.

• Wrong coolant mix.
  Despite what some believe pure antifreeze does not cool as well as a 50/50 mix of water and antifreeze, nor does pure water. Antifreeze conditions the water to increase the boiling point, protect parts from corrosion or rusting, and to prevent the water from freezing. You can get testers from your auto store for a couple of bucks that will tell you how much water or antifreeze to add.

• Stuck thermostat.
  This is also an obvious one. If it is stuck closed coolant can't flow through the radiator to cool back down.

• Bad radiator cap.
  The radiator cap doesn't just seal the radiator. It is rated for a pressure. The pressure in the system increases the boiling point in the system. If the spring in the cap is bad the system will not build pressure. Low pressure = low boiling point. When the coolant begins to boil it turns to steam and as you can guess steam does not cool very well.

• Missing thermostat
  Wait if the thermostat was missing wouldn't there be nothing to slow down the flow to let it get warm? Actually no, since the thermostat is missing there is no restriction to build pressure inside the engine, again without the pressure the boiling point goes down and you start getting steam inside the engine which causes it to overheat.