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How to Bleed the Coolant System in a 1999 Oldsmobile Silhouette

by Tim Petruccio

The Oldsmobile Silhouette was introduced in 1990. The 1999 Silhouette came equipped with a 185-horsepower 3.4-liter V6 engine. The cooling system on the 1999 Silhouette can obtain air in the system through a variety of malfunctions. Air pockets are formed in the cooling system when engine coolant flows out of the vehicle for any reason. The 1999 Silhouette uses standard or universal coolant, which can be obtained at auto parts stores. The amount of coolant needed depends on if the van is equipped with a rear heater as well as a standard.

Allow the engine to cool for no less than 2 hours if you have recently driven the van. Raise the hood on the Silhouette and set the hood prop, after the engine has cooled. Visually inspect the top of the radiator to locate the radiator cap.

Place a drain pan under the car, directly beneath the radiator cap area. Open the radiator cap if it is cool to the touch. If the radiator cap is hot or very warm, allow the van to cool for at least 1 more hour. Remove the cap only when the cap is lukewarm or cool to the touch.

Install a pair of locking pliers or a radiator hose-hand clamp onto the upper radiator hose, on the driver's side of the engine. Squeeze the hose completely shut. Add engine coolant to the radiator until it is nearly full. Leave the radiator cap off at this time.

Turn the engine on and let the engine run for no less than 15 to 20 minutes. Turn the heater control switches to full heat, defrost mode and full fan speed. Turn the rear heater on at full fan speed and full heat, if equipped.

Check the coolant level frequently, and add coolant when you can begin to see the silver fins inside the radiator. Continue adding coolant until the radiator stays full, and there are no more signs of air pockets. Assuming your van engine is running at a smooth idle, the coolant level in the radiator should stay steady. A rough idle will cause the level to go up and down with the speed of the water pump. Allow the engine to run for 5 minutes beyond the point where you see the last air bubble.

Remove the upper pliers or clamp from the upper radiator hose, with the engine still running. Fill the radiator until it is completely full. Allow the engine to run for approximately 5 more minutes after your final radiator filling.

Shut the engine off, then install the radiator cap. Make sure the cap is tightened to the second notch or rotation. The first 90 degrees a radiator cap is turned is a vent release position. The second 90-degrees locks the cap down completely. Add coolant to the radiator overflow reservoir. Read the reservoir caps carefully so as not to add coolant to your wiper fluid reservoir.

Warning

  • Engine coolant contains Ethylene Glycol, which is extremely poisonous to humans and animals. Ethylene Glycol poisoning can cause symptoms of instant nausea. If you feel nauseous at all during this project, stop the project and seek immediate medical attention. Wash any skin that comes in contact with engine coolant, in warm soapy water, for no less than 5 minutes. Rinse any spill out of your work area by saturating the area in water.

Items you will need

About the Author

Tim Petruccio is a professional writer and automotive mechanic. His writing combines more than 20 years of mechanical experience in automotive service, service management, automotive education and business ownership. He assisted in the automotive beta, which launched March 2011.

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