1998 Nissan Frontier Owner's Manual - Page 151

ENGINE COOLING SYSTEM The engine cooling system is filled at the factory with a high-quality, year-round, antifreeze coolant solution. The anti-freeze solution contains rust and corrosion inhibitors, therefore additional engine cooling system additives are not necessary. CAUTION When adding or replacing coolant, be sure to use only an ethylene glycol anti-freeze with the proper mixture ratio of 50% anti-freeze and 50% distilled water. The use of other types of coolant solutions may damage the engine cooling system. Outside temperature down to °C −35 °F −30 50% 50% burns could be caused by high pressure fluid escaping from the radiator. See precautions in ''If your vehicle overheats'' found in the ''In case of emergency'' section of this manual. ● The radiator is equipped with a pressure cap. Use only a genuine NISSAN cap as it's replacement. ADI1026 CHECKING ENGINE COOLANT LEVEL Check the coolant level in the reservoir tank when the engine is cold. If the coolant level is below the MIN level, add coolant to the MAX level. If the reservoir tank is empty, check the coolant level in the radiator when the engine is cold. If there is insufficient coolant in the radiator, fill the radiator with coolant up to the filler opening and also add it to the reservoir tank up to the MAX level. Antifreeze Distilled water WARNING ● Never remove the radiator cap when the engine is hot. Wait until the engine and radiator cool down. Serious 8-4 Do-it-yourself