1995 GMC Jimmy Owner's Manual - Page 217

If the coolant inside the coolant recovery tank is boiling, don't do anything else until it cools down. ADD mark. If it isn't, you may have a The coolant level should be at the leak in the radiator hoses, heater hoses, radiator, water pump somewhere or else in thecooling system. I NOTICE: Engine damage from running your engine without coolant isn't covered by your warranty. If there seems to be no leak, start theengine again. See if the fan speed increases when idle speed is doubled by pushing the accelerator pedal down. If it doesn't, your vehicle needsservice. Turn off the engine. 5-15