Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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HOMESERVICE MANUALSGMC1999FORWARD CONTROL 5.7 R, AUTOMATICREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 800 (ENGINE COOLING SYSTEM)REPAIR INSTRUCTIONSDRAINING AND FILLING COOLING SYSTEMDRAINING PROCEDURE
1999 GMC Forward Control 5.7 R, Automatic
Draining Procedure
1999 GMC Forward Control 5.7 R, AutomaticSECTION Draining Procedure
WARNING: This page is about a different car, the 2003 Buick Regal and 2003 Buick Century. However, it is still accessible from the selected car via links, so may be relevant.
CAUTION:
With a pressurized cooling system, the coolant temperature in the radiator can be considerably higher than the boiling point of the solution at atmospheric pressure. Removal of the surge tank cap, while the cooling system is hot and under high pressure, causes the solution to boil instantaneously with explosive force. This will cause the solution to spew out over the engine, the fenders, and the person removing the cap. Serious bodily injury may result.
- Park the vehicle on a level surface.
- Remove the coolant pressure cap.
- Raise and support the vehicle. Refer to LIFTING AND JACKING THE VEHICLE in General Information.
- Place a drain pan under the drain cock.
- Open the radiator drain cock.
- Drain the cooling system.
- If a complete engine block drain is required, remove the engine block drain plug.
- Inspect the coolant.
- Follow the appropriate procedure based on the condition of the coolant.
- Normal in appearance - follow the filling procedure.
- Discolored - follow the flush procedure. Refer to FLUSHING .
RENDER: 1.0x
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.