Note: The crankshaft can only be removed after the engine has been removed from the vehicle. Remove the flywheel first (or leading disk), tensioner pulley, chain, sump, oil receiver, oil pump (on V6), front cover and connecting rods with pistons.
1. Preliminarily check the axial play of the crankshaft (photo). To do this, move the crankshaft towards the rear of the engine, applying maximum force, and in this position set the indicator scale to zero. Then push the crankshaft towards the front of the engine and read the indicator readings. The value of the axial play is equal to the distance the shaft has moved. If the axial play exceeds the standard value, check the wear of the thrust surfaces of the crankshaft cheeks. If the wear is insignificant, the play should be compensated by installing new main bearings. The play can be measured with feeler gauges, laying them between the end of the 3rd main bearing (or 4th on V6 engines) and the crankshaft cheek.
12.1a Checking the crankshaft axial play with an indicator...
12.1b...or with a feeler gauge
2. Check the covers for orientation arrows and cylinder number markings. Covers are usually numbered starting from the front of the engine. If there is no marking, make marks with a punch. Loosen the cover bolts by 1/4 turn at a time in the reverse order shown (photo), until the bolts can be unscrewed by hand.
12.2a Marking of main bearing caps
12.2b Sequence for loosening the cover bolts on 4-cylinder engines...
[Material borrowed from the website: NISSANBOOK.ru]
12.2v...and on V6 engines
3. Carefully move the main bearing caps and remove them together with the liner. On 4-cylinder engines, the rear and middle bearing caps are removed with a device (photo). On V6 engines, the caps are cast into a single frame.
12.3 Removing covers on 4-cylinder engines
4. Carefully remove the crankshaft. Install the covers with liners in the same order and tighten the bolts by hand.