Discolored Coolant in cooling System & Contamination of Reservoir TSB # 00-06-02-005
2000 Buick LeSabre & Pontiac Bonneville with 3.8L Engine (VIN'* K, 1 -- RPO'* L36, L67)
Some customers may comment about discolored coolant (usually dark & rust colored in appearance) and a ring of contamination material around the inside of the coolant recovery reservoir.
This condition may be caused by excess seal pellet (stop leak) residue material from sealler pellets installed at the assembly plant. Sealer pellet installation has since been discontinued on the above vehicles.
This condition is almost always confined to the coolant revery reservoir, so it is not necessary to change the coolant. Clean the coolant recovery reservoir & test the radiator cap for proper function. Keeping the cooling system full at all times & performing the following proceedure should eliminate future recurrence.
1) Remove the coolant recovery reservoir.
2) Clean inside of the coolant recovery reservoir using soap & water. Thoroughly rinse the reservoir with clean water & drain.
3) Install the coolant recovery reservoir.
4) Test the radiator cap.
5) Refill the coolant recovery reservoir with a 50/50 mixture of DEX-COOL and clean drinkable or distilled water to the FULL HOT mark. Fill to the FULL HOT mark to compensate for any air that may be in the cooling system.
6) Top off the radiator, if necessary.
7) Instruct the customer of the importance of maintaining the proper coolant level in the radiator & cooling recovery reservoir.