1994 Buick LeSabre Owner's Manual - Page 198
1994 Buick LeSabre Manual
Page 198 highlights
How to Add Coolant to the Coolant Recovery Tank If you haven't found a problem yet, but the coolant level isn't at or above the "FULL COLD" mark, add a 50/50 mixture of clean water (preferably distilled) and a proper antifreeze at the coolant recovery tank. (See "Engine Coolant" in the Index for more information about the proper coolant mix.) I NOTICE: In cold weather, water can freeze and crack the engine, radiator, heatercore and other parts. Use the recommended coolant. 196