Nissan QG18DE Specifications
| Engine Model: Nissan QG18DE |
| Engine Type: 4-cycle inline 4-cylinder DOHC 16-valve liquid-cooled gasoline |
| Total Displacement: 108 cu.in (1.77 L) |
| Rated Engine Power: 115-125 Hp (85-93 kW) at 6000 rpm |
| Fuel System Type: Multi-point electronic fuel injection (MPFI) |
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The Nissan QG18DE engine is a 1.8-liter,
inline-four, four-stroke, water-cooled gasoline engine introduced as
part of Nissan’s QG-series in the late 1990s and early 2000s. It powered
numerous compact and mid-size Nissan models around the world, including
the Nissan Sentra, Almera, Pulsar, Primera (entry-level variants),
Wingroad, and several regional vehicles.
The engine combines fuel economy, stability, and long-term durability
with modern engineering such as multi-point electronic fuel injection,
coil-on-plug ignition, and a chain-driven DOHC valvetrain. The QG18DE
provides robust low- and mid-range torque suitable for daily commuter
driving.
It was engineered for low emissions, long service intervals, and the
ability to operate in demanding climates. Balanced power delivery, a
conservative RPM limit, and a reliable internal architecture make the
QG18DE one of Nissan’s most service-friendly small displacement engines.
The QG18DE displaces approx. 1,769 cc (108.0 cu in). Bore is approx.
80.0 mm (3.15 inches) and stroke is approx. 88.0 mm (3.46 inches). This
long-stroke configuration emphasizes torque over high-RPM output.
Compression ratio is 9.5:1. Maximum power output is 115-125 hp at
5,600-6,000 rpm depending on model and region. Maximum torque is 118-125
lb-ft (160-170 Nm) at approx. 2,800-4,000 rpm. Idle speed is 700-750
rpm. The firing order is 1-3-4-2. Redline is around 6,500 rpm.
The cast-iron block offers durability and low noise transmission. The
crankshaft is forged steel with five main bearings, providing excellent
stability. Pistons are aluminum alloy with low-friction coatings and
three-ring packs.
Connecting rods are forged steel with floating wrist pins. The rotating
assembly is balanced for smoothness, supporting low maintenance
requirements. Oil passages and crankcase ventilation are optimized for
clean operation and long service life.
The aluminum DOHC cylinder head features four valves per cylinder.
The valvetrain incorporates:
- Chain-driven camshafts
- Roller rocker arms
- Hydraulic lash adjusters
- Camshaft timing optimized for efficiency and torque
The combustion chamber is compact and engineered to produce effective
swirl and tumble for efficient combustion. The timing chain uses a
hydraulic tensioner that is self-adjusting, requiring no replacement
under standard maintenance intervals. The intake and exhaust port
geometry is designed to balance torque and economy.
The QG18DE uses a multi-point electronic fuel-injection (MPFI) system.
Fuel system components include:
- Electric fuel pump (in-tank)
- High-pressure fuel rail
- Multi-hole injectors
- Mass-airflow (MAF) sensor
- Engine Control Module (ECM)
- Electronic throttle body (varies by region)
Fuel pressure is 43-50 psi.
The ECM coordinates injection timing using
signals from:
- O2 sensors
- Crankshaft position sensor
- Camshaft position sensor
- Coolant temperature sensor
- Throttle-position sensor
- Knock sensor
This system delivers consistent economy, emissions compliance, and
strong mid-range response.
The lubrication system is a full-pressure, wet-sump configuration using
a crankshaft-driven oil pump.
Specifications:
- Oil capacity: 3.5-3.8 liters (3.7-4.0 US qt)
- Operating oil pressure: approx. 45-65 psi at 3,000 rpm; approx. 15-20
psi at idle
- Recommended oil: 5W-30 or 10W-30 synthetic or semi-synthetic
Oil is distributed to crankshaft journals, rod bearings, camshafts,
timing components, and hydraulic lifters. The engine uses a full-flow
spin-on filter. Proper oil maintenance ensures long timing-chain life.
The QG18DE cooling system uses a belt-driven centrifugal water pump.
System components include:
- Aluminum-core radiator
- Thermostat
- Electric cooling fans
- Coolant passages in block and head
Specifications:
- Thermostat begins opening at approx. 82°C (180°F)
- Fully open at approx. 95°C (203°F)
- Cooling-system capacity: 6.0-6.5 liters (6.3-6.8 US qt)
The system is designed to maintain stable temperature even in high
ambient conditions.
| Intake and Exhaust Systems |
The induction system includes:
- Air-filter housing
- Replaceable paper filter
- Intake snorkel
- MAF sensor
- Plastic long-runner intake manifold
- Throttle body
Runner geometry enhances mid-range torque. The MAF sensor provides
precise measurement of airflow.
The exhaust system features:
- Cast or stainless-steel exhaust manifold
- Close-coupled catalytic converter
- Underbody catalytic converter (market dependent)
- Oxygen sensors (pre- and post-cat)
- Exhaust piping and muffler
The system supports emissions compliance while maintaining torque
characteristics.
The ignition system is fully electronic, utilizing coil-on-plug (COP)
technology.
Components include:
- Four individual ignition coils
- Platinum or iridium spark plugs
- Crankshaft angle sensor
- Camshaft angle sensor
- ECM-controlled spark advance
Spark-plug gap ranges 0.9-1.1 mm (0.035-0.043 inches). The ECM adjusts
ignition timing for knock control and efficiency.
- Length: 650-700 mm (25.6-27.6 in)
- Width: 600-630 mm (23.6-24.8 in)
- Height: 650-700 mm (25.6-27.6 in)
Dry weight: 120-135 kg (265-298 lb) depending on accessories
Recommended service intervals:
- Oil and filter: every 5,000-10,000 km (3,000-6,000 mi)
- Air filter: every 20,000 km (12,000 mi)
- Spark plugs: every 40,000-60,000 km
- Coolant: every 2-3 years
- Drive belts: inspect every 20,000-30,000 km
- Fuel filter: non-serviceable (in-tank)
Compression pressure:
- Approx. 160-190 psi
- Variation: less than 10 percent
Idle should remain stable at approx. 700-750 rpm.
- Cylinder-head bolts: approx. 75-85 lb-ft (102-115 Nm)
- Main-bearing-cap bolts: approx. 55-65 lb-ft (75-88 Nm)
- Connecting-rod bolts: approx. 30-35 lb-ft (40-48 Nm)
- Flywheel bolts: approx. 70-80 lb-ft (95-108 Nm)
- Intake-manifold bolts: approx. 18-22 lb-ft (24-30 Nm)
- Exhaust-manifold nuts: approx. 25-30 lb-ft (34-40 Nm)
- Spark plugs: approx. 15-20 lb-ft (20-27 Nm)
- Oil-drain plug: approx. 25-30 lb-ft (34-40 Nm)
The QG18DE engine appeared in:
- Nissan Sentra / Sunny / Pulsar
- Nissan Almera and Almera Tino
- Nissan Wingroad
- Nissan Primera (entry-level models)
- Regional Nissan sedans and MPVs
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