1995 GMC Sonoma Owner's Manual - Page 241

To Check Coolant When your engineis cold, the coolantlevel should be at ADD, or a little higher. When your engine is warm, the level should be up to FULL HOT, or a little higher. To Add Coolant If you need more coolant, add the proper mix at the coolant recovery tank. A CAUTION: Nrning the radiatorpressure cap when the engine and radiator are hot can allow steam and scalding liquids to blow out and burn you badly.With the coolant recoverytank, you will almost never have to add coolant at the radiator. Never turn the radiator pressure cap - even a little -when the engine and radiator are hot. Add coolant mix at the recovery tank, but be careful not to spill it. A CAUTION: You can be burned if you spill coolant on engine parts. hot Coolant contains ethylene glycol,and it will burn if the engine parts are enough. Don't spill coolant on hot engine. hot a Radiator Pressure Cap NOTICE: Your radiator cap is a 15 psi (105 kPa) pressure-type cap and must be tightly installedto prevent coolant lossand possible engine damage from overheating. Be sure the arrows on the cap line up with the overflow tube on the radiator filler neck. 6-23