Nissan Sentra Service Manual: Precautions For Engine Service

DISCONNECTING FUEL PIPING

• Before starting work, check no fire or spark producing items are in the work area.
• Release fuel pressure before disconnecting and disassembly.
• After disconnecting pipes, plug openings to stop fuel leakage.

DRAINING ENGINE COOLANT

Drain engine coolant and engine oil when the engine is cooled.

INSPECTION, REPAIR AND REPLACEMENT

Before repairing or replacing, thoroughly inspect parts. Inspect new replacement parts in the same way, and replace if necessary.

REMOVAL AND DISASSEMBLY

• When instructed to use SST, use specified tools. Always be careful to work safely, avoid forceful or uninstructed operations.
• Exercise maximum care to avoid damage to mating or sliding surfaces.
• Dowel pins are used for several parts alignment. When replacing and reassembling parts with dowel pins, check that dowel pins are installed in the original position.
• Must cover openings of engine system with a tape or equivalent, to seal out foreign materials.
• Mark and arrange disassembly parts in an organized way for easy troubleshooting and reassembly.
• When loosening nuts and bolts, as a basic rule, start with the one furthest outside, then the one diagonally opposite, and so on. If the order of loosening is specified, do exactly as specified. Power tools may be used in the step.

ASSEMBLY AND INSTALLATION

• Use torque wrench to tighten bolts or nuts to specification.
• When tightening nuts and bolts, as a basic rule, equally tighten in several different steps starting with the ones in center, then ones on inside and outside diagonally in this order. If the order of tightening is specified, do exactly as specified.
• Replace with new gasket, packing, oil seal or O-ring.
• Thoroughly wash, clean, and air-blow each part. Carefully check engine oil or engine coolant passages for any restriction and blockage.
• Avoid damaging sliding or mating surfaces. Completely remove foreign materials such as cloth lint or dust.

  Before assembly, oil sliding surfaces well.

• After disassembling, or exposing any internal engine parts, change engine oil and replace oil filter with a new one.
• Release air within route when refilling after draining engine coolant.
• After repairing, start the engine and increase engine speed to check engine coolant, fuel, engine oil, and exhaust gases for leakage.