With filter change 4.1 L (4-3/8 US qt, 3-5/8 Imp qt) Maintenance data Valve clearance (HOT)Ĭompression differential limit between cylinders The MR18DE motor life expectancy is 200,000 miles of mileage (300,000 km) or more. The valve clearance needs to be adjusted every 60,000 miles of mileage (90,000 km). The engine has a timing chain, their service life is about 150,000 miles of mileage (200,000-250,000 km). It needs to tighten or replace the old belt by a new one. This engine sometimes has a problem with alternator belt (whistle noise). Head tightening procedure and torque specs:
This system returns a portion of the exhaust gas to the intake side to reduce fuel consumption and minimize emission. The MR18DE is equipped with EGR (Exhaust Gas Recirculation) system. The engine has a plastic intake manifold with an integrated tumble control valve. The MR18DE motor does not have hydraulic lifters, so special valve lifters are used to adjust the valve clearance. Intake valves are 34 mm in diameter, intake duration is 224°, and the exhaust valves are 27.6 mm, exhaust duration is 212°. Enhanced control and reduced system friction improve response and optimize torque characteristics. C-VTC enables variable valve timing in response to engine rpm and throttle opening. The MR18DE has continuous variable valve timing system (C-VTC) on the intake camshaft. Each camshaft is supported by five bearings. The cylinder head is made of strong, light aluminum alloy which gives it good cooling efficiency. Number of piston rings (compression / oil): The Nissan MR18DE motor has two compression and one oil control rings. The cylinder bore is 84.0 mm (3.3 in) and the piston stroke is 81.1 mm (3.19 in) and compression ratio rating is 9.9:1. The result is a thorough reduction in friction on these bearing surfaces of key engine components. The crankshaft and camshaft journals are finished with a polishing tape to produce a mirror-like finish. This permits more efficient use of combustion energy and effectively improves thermal efficiency. Also, the structure is designed so that the piston remains in the upper part of the cylinder longer than in a conventional engine (piston velocity slows down).
The resulting smoother reciprocating motion of the pistons contributes to high power output and high torque as well as fuel economy. Cylinders in the Nissan MR18DE engines are fitted at an offset to minimize friction arising from the angle of the connecting rod as a piston descends into the cylinder. The MR18DE has an aluminum cylinder block with a five-bearings crankshaft supported system. The MR-family engines use the same technology as in the HR-series.
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