How to Drain the Radiator on a 2002 Buick LeSabre

by Richard Rowe

    Some might say that the Buick LeSabre's apple fell a long way from its original tree as America's most important concept car. Among the 1951 concept's many ahead-of-their-time features was a power hard-top activated by a rain sensor between the front seats. By the car's eighth and final generation, the Buick might have been little more than a rebadged Pontiac Bonneville -- however, the LeSabre's many luxury amenities were still enough to retain its crown as America's best selling full-sized car until the Lucerne replaced it in 2006. Never mind historical ideals -- that's the kind of fruit you can take to the bank.

    Items you will need

    • Wheel chocks
    • Floor jack
    • Jack stands
    • Pliers
    • Drain pan
    • Clean rag
    • Ratchet
    • Socket set
    • Soap and water
    • Torque wrench
    • 10 quarts 50/50 mix of distilled water and Dex-Cool coolant
    • Radiator flush (optional)
    • Wrench set
    Step 1

    Set the car's parking brake, chock its rear wheels and allow the engine to cool. Lift the front of the car with a floor jack and secure it on jack stands. Remove the radiator cap and slide a drain pan under the driver side of the radiator.

    Step 2

    Crawl under the car and look up at the engine side of the driver-side radiator tank. You'll see the radiator petcock plug; it's a black, plastic, circular plug with a fin sticking out of the top. Use a pair of pliers to grasp the fin and turn the petcock counterclockwise to open it. The fluid will begin to drain out though the valve.

    Step 3

    Wait for all the fluid to drain out, then close the petcock valve. Turn your attention to the plastic coolant recovery tank. Remove the three nuts and bolts that hold it to the car with a ratchet and socket, and disconnect the recovery tank's hose clamp with the pliers. Use some soap and water to thoroughly clean the tank out. If there's rust built up on the inside, you may wish to clean it with a bit of commercial calcium-lime-rust remover.

    Step 4

    Rinse the tank out thoroughly and reinstall it. Tighten the mounting bolts to 53 inch-pounds with a torque wrench. Clean the radiator cap and the inside of the radiator filler neck with clean water. If your coolant came out rusty and nasty, or full of dirt and debris, then this is the time to run some radiator flush through the system. Buy some cooling system flush and follow the manufacturer's recommended flushing procedure before proceeding.

    Step 5

    Fill the radiator and the overflow reservoir to the "Cold" line with the recommended coolant. Wait two minutes and recheck the level -- it should be at the base of the radiator filler neck. Install the radiator cap, and twist it down tightly to seal it.

    Step 6

    Put the heater's temperature control on its maximum setting, and put the fan speed on "Low." If you have automatic temperature control, that means temperature at the highest setting and the climate control in any setting except for "A/C Max."

    Step 7

    Start the engine and allow it to idle until the lower radiator hose gets hot. Cycle the engine speed up to 3,000 rpm and back down to idle five times. Follow the upper radiator hose to the thermostat housing on the engine, and note the hexagonal bleed valve you see on the housing.

    Step 8

    With the engine running, use a wrench to very slowly open the bleed valve; be extrelemy careful, as it will likely vent scalding steam. Allow the vent to remain open for approximately 15 seconds to vent trapped air from the cooling system. Close the bleed valve snug, but do not overtighten it.

    Step 9

    Allow the engine to cool, then check the coolant level in the overflow tank. It should be sitting at the "Cold Full" line. Top up with coolant mix as necessary.


    • ProDemand; 2002 Buick LeSabre; Service Manual; Engine Cooling System; Draining and Filling the Cooling System