1993 Buick Riviera Owner's Manual - Page 201

I A CAUTION: Heater and radiator hoses, and other engine parts, can be very hot. Don't touch them. If you do, you can be burned. Don't run the engine if there is a leak. If you run the engine, it could lose all coolant. That could cause an engine fire, and you could be burned. Get anyleak fixed before you drivethe vehicle. ' ~ - - # I 1 .': ..~ /I I_ '1 , A CAUTION: Adding only plain water to your cooling system can be dangerous. Plain water, or some other liquid likealcohol, can boil before the proper coolant mix will. Your vehicle's coolant warning system is set for the proper coolant mix. With plain water or the wrong mix, your engine could get too hot but you wouldn't get the overheat warning. Your engine could catch fire and you or others could be burned. Use a 5060 mix of clean water and a proper antifreeze.