1993 Buick Skylark Owner's Manual - Page 201

How to Add Coolant to the Coolant Surge Tank If you haven't found a problem but the coolant level yet, "FULL COLD," add a50/50 mixture of isn't at or above clean water (preferably distilled) and the proper antifreeze at the coolant surge tank, but be sure the cooling system, including the coolant surge tank pressure cap, is cool before you it. (See "Engine do Coolant" in the Index more information about the for proper coolant mix.) /I\ CAUTION: Steam and scalding liquids froma hot cooling system can blow out and burn you badly. They are under pressure, and if you turnthe coolant surge tank pressure cap -- even alittle they can come out at high speed. Never turn the cap when lhe cooling system, including the coolant surge tank pressure cap, is hot. Wait for the coolinsystem and coolant surge tank pressure cap 1 3 cool if you ever have to turnthe pressure cap. -- t