1997 GMC Savana Van Owner's Manual - Page 246

Among those acts presumed to constitute tampering are the acts listed below. Engine Oil (Gasoline Engine) If your vehicle hasa diesel engine, see "Engine Oil (Diesel Engine)" in the Diesel Engine Supplement. It's a good idea to check your engine oil every timeyou get fuel. In order to get anaccurate reading, the oil must be warm and the vehicle must be on level ground. Turn off the engine and give the oil a few minutes to drain back into the oil pan. If you don't, the oil dipstick might not show the actual level. Insulation: Removal of the noise shields or underhood insulation. Engine: Removal or rendering engine speed governor (if equipped) inoperative so as to allow engine speed to exceed manufacturer specifications. Fan and Drive: Removal of fan clutch (if equipped) or rendering clutch inoperative. Removal of the fan snroud (if equipped). Air Intake: Removal of the air cleaner silencer. Reversing the air cleaner cover. Exhaust: Removal of the muffler and/or resonator. Removal of the exhaust pipes and exhaust pipe clamps. 6-12