Mazda GY-DE Specifications
| Engine Model: Mazda GY-DE |
| Engine Type: 4-cycle 6-cylinder V-block DOHC 24-valve liquid-cooled gasoline |
| Total Displacement: 152.3 cu.in (2.49 L) |
| Rated Engine Power: 168 Hp (125 kW) at 6250 rpm |
| Fuel System Type: Multi-point electronic fuel injection |
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The Mazda GY-DE is a 2.5-liter V6 gasoline engine
manufactured by Mazda in Japan under license from Ford, utilizing the Duratec V6
architecture. Produced between 1999 and 2002, the GY-DE was developed
specifically for the second-generation Mazda MPV (LW series) prior to the
vehicle’s first major facelift. The engine represents a collaboration between
Mazda and Ford, sharing its fundamental design with the Ford Duratec 25 (LCBD)
and Jaguar AJ25 V6 engines while carrying Mazda-specific calibration and
ancillary components.
Constructed entirely from aluminum alloy, the GY-DE features a chain-driven dual
overhead camshaft (DOHC) valvetrain with 24 valves and hydraulic lash adjusters.
The engine was positioned to deliver a balance of smoothness, power output, and
packaging efficiency suitable for the MPV’s front-wheel-drive transverse layout.
Engine Type: 60° V6, 4-cycle, water-cooled, gasoline.
Displacement: 2,495 cc (152.3 cu.in).
Bore: 82.4 mm (3.24 in).
Stroke: 79.5 mm (3.13 in).
Compression Ratio: 9.7:1.
Firing Order: 1-4-2-5-3-6 (left bank cylinders 1, 2, 3; right bank cylinders 4,
5, 6).
Maximum Power Output: 168 hp (125 kW) @ 6,250 rpm.
Maximum Torque Output: 207-211 Nm (153-155 lb-ft) @ 5,000 rpm.
Valvetrain Configuration: Dual Overhead Camshaft (DOHC) per cylinder bank,
operating 24 valves (4 valves per cylinder). Each bank features two chain-driven
camshafts. Hydraulic lash adjusters are incorporated into the valvetrain,
eliminating routine manual valve clearance adjustments.
The cylinder block is manufactured from aluminum alloy
with a 60-degree V-angle configuration. Cast iron cylinder liners are integrally
cast into the block to provide wear-resistant bore surfaces. Bore diameter
measures 82.4 mm (3.24 in). The block features a deep-skirt design extending
below the crankshaft centerline with a structural aluminum lower crankcase
(bedplate) that replaces individual main bearing caps, enhancing rigidity while
maintaining lightweight construction.
The crankshaft is forged steel with six counterweights, supported by four main
bearings. The block incorporates integrated oil galleries and mounting points
for transverse engine orientation in front-wheel-drive chassis. Cylinder bores
are machined with a plateau honed finish for optimal piston ring seating and oil
retention.
Each cylinder head is manufactured from aluminum alloy
with pent-roof combustion chambers and cross-flow port architecture. Hydraulic
Lash Adjusters: Direct-acting units mounted in the cylinder head casting,
operating on the cam followers. These adjusters automatically maintain zero
valve clearance throughout engine life using engine oil pressure.
Valve Count: 24 total; 12 intake, 12 exhaust.
Intake Valve Diameter: 31.0 mm (1.22 in).
Exhaust Valve Diameter: 26.0 mm (1.02 in).
Valve Stem Diameter: 6.0 mm (0.24 in) for both intake and exhaust.
Valve Guides: Press-fit sintered iron guides.
Valve Seat Inserts: Powder metal sintered alloy with multi-angle seat geometry
(three-angle intake, two-angle exhaust).
Camshafts: Chilled cast iron camshafts with induction-hardened lobes. Each bank
contains two camshafts (intake and exhaust) driven by a primary timing chain
from the crankshaft. A secondary chain or gear train transmits drive between the
intake and exhaust camshafts on each bank.
Valve Timing: Intake camshaft duration is 248 degrees at 1.0 mm lift; exhaust
camshaft duration is 248 degrees at 1.0 mm lift. No variable valve timing is
incorporated in the GY-DE designation.
The fuel system employs multi-point electronic fuel
injection with sequential injection timing. Fuel Injection Type: Sequential
multi-port injection with fuel injectors positioned in the intake manifold
runners adjacent to each intake port. Fuel Pressure: Regulated to 2.5-3.0 bar
(36-44 psi) via a vacuum-referenced fuel pressure regulator mounted on the fuel
rail.
Engine Management System: Mazda-engineered ECU utilizing inputs from a mass
airflow sensor (hot-wire type), throttle position sensor, coolant temperature
sensor, intake air temperature sensor, crankshaft position sensor, camshaft
position sensors, and dual oxygen sensors (one per bank). Injector Flow Rate:
Approximately 210-230 cc/min at standard operating pressure.
Fuel Pump: In-tank electric fuel pump with a mesh pre-filter. The pump assembly
includes a non-serviceable filter that requires tank removal and pump
replacement if clogging occurs. Intake Manifold: Aluminum manifold with
individual runners per cylinder. The manifold incorporates a resonance chamber
and is equipped with a throttle body positioned centrally between the cylinder
banks.
The lubrication system is a full-flow, pressurized type
utilizing a rotor-type oil pump driven by the crankshaft. Oil Pump Type:
Internal gear (gerotor) pump mounted to the front of the crankshaft, housed
within the front timing cover assembly. Oil Capacity: 5.2 liters (5.5 qt)
including oil filter replacement. Recommended Oil Viscosity: 5W-30.
Oil Quality Requirement: API SJ, SL, or later classifications. ACEA A3/B3 or
A3/B4 for European market variants. Oil Pressure: At warm idle, pressure ranges
from 1.0-1.8 bar (14-26 psi); at 3,000 rpm, pressure reaches 3.5-4.5 bar (51-65
psi). Oil Filter: Full-flow spin-on canister type mounted to the cylinder block
adjacent to the oil pump housing. Access is positioned for service from the
under-vehicle location.
The cooling system is pressurized and utilizes a
centrifugal water pump driven by the timing chain or accessory belt depending on
the specific front-end accessory drive configuration.
Water Pump Type: Centrifugal pump with a die-cast aluminum housing and stamped
steel impeller. The water pump is recessed into the front of the engine and is
driven by the timing chain on this architecture, requiring timing component
removal for replacement.
Thermostat: Wax-pellet type located in the coolant outlet housing at the front
of the engine. Opening temperature is 82-88 °C (180-190 °F). Coolant Capacity:
7.5-8.5 liters (7.9-9.0 qt) inclusive of engine block, heater core, and
radiator. Coolant Specification: Ethylene glycol-based coolant with corrosion
inhibitors suitable for aluminum engine construction.
Radiator: Cross-flow aluminum core with plastic end tanks sized for the
transverse V6 layout. Cooling fan configuration consists of dual electric fans
controlled by the engine control unit based on coolant temperature and air
conditioning load. System Pressure: Radiator cap rated at 1.1 bar (16 psi).
| Intake and Exhaust Systems |
Exhaust System: Cast iron exhaust manifolds with
individual collectors per bank, merging into a single exhaust pipe downstream. A
dual catalytic converter system (one per bank) is utilized for emissions control
with oxygen sensors positioned before and after each catalyst.
Intake System: Air induction utilizes a large-volume air cleaner housing with a
resonator to reduce induction noise. The throttle body incorporates an
electronically controlled idle air control valve.
Distributorless ignition system with individual
pencil-type ignition coils mounted directly over each spark plug (coil-on-plug).
The system utilizes a crankshaft position sensor and dual camshaft position
sensors for sequential ignition timing. No moving distributor components are
present.
Spark Plug Type: NGK PTR5A-10 or equivalent.
Spark Plug Gap: 1.0-1.1 mm (0.039-0.043 in).
Timing System: Maintenance-free timing chain system. A
primary chain drives the intake camshaft of each bank from the crankshaft. A
secondary chain on each bank transmits drive from the intake camshaft to the
exhaust camshaft. Hydraulic chain tensioners supplied by the engine lubrication
circuit maintain tension. The system is intended for the engine service life,
though tensioner wear is monitored during routine maintenance.
Crankcase Ventilation: Positive Crankcase Ventilation (PCV) system with a PCV
valve mounted on one cylinder bank and a balance tube connecting both banks to
ensure even crankcase pressure distribution.
Engine Mounting: Designed for transverse orientation in front-wheel-drive
chassis. Three-point mounting system utilizes a front roll restrictor, a
right-hand hydraulic mount, and a left-hand transmission mount.
Overall Length: 660 mm (26.0 in) measured from
accessory drive pulley face to transmission mounting flange.
Overall Width: 680 mm (26.8 in) inclusive of intake manifold, throttle body, and
exhaust manifold heat shields.
Overall Height: 710 mm (28.0 in) from oil pan bottom surface to valve cover top
surface.
Dry Weight: 145-155 kg (320-342 lb) depending on intake manifold configuration
and accessory drive components.
Timing Chain Inspection Interval: Chain, tensioners,
and guides inspection recommended at 120,000 km (75,000 miles). Replacement is
condition-based. Water Pump Replacement: The water pump is driven by the timing
chain and is inaccessible without removing timing components. Replacement is
often performed concurrently with timing chain service.
Spark Plug Replacement Interval: 96,000 km (60,000 miles). Spark Plug Torque:
20-25 Nm (15-18 lb-ft). Drive Belt Tension (Accessory): 8-10 mm (0.31-0.39 in)
deflection under 10 kg (22 lb) of force at the midpoint of the longest span.
Automatic tensioner is used for the serpentine belt.
Coolant Change Interval: 48,000 km (30,000 miles) or 2 years. Engine Oil Change
Interval: 7,500-10,000 km (4,700-6,200 miles) depending on operating conditions.
Idle Speed (warm, neutral): 700-750 rpm. Ignition Timing: Electronically
controlled with no manual adjustment provision.
Cylinder Head Bolts (cold): Step 1: 30 Nm (22 lb-ft).
Crankshaft Damper Pulley Bolt: 180-200 Nm (133-148 lb-ft).
Connecting Rod Cap Bolts: 25 Nm (18 lb-ft).
Main Bearing Cap Bolts (bedplate-to-block), Step 1: 20 Nm (15 lb-ft).
Main Bearing Cap Bolts (bedplate-to-block), Step 2: 50 Nm (37 lb-ft).
Camshaft Bearing Cap Bolts: 10-12 Nm (7-9 lb-ft).
Camshaft Sprocket Bolts: 80-90 Nm (59-66 lb-ft).
Valve Cover Bolts: 8-10 Nm (6-7 lb-ft).
Intake Manifold Bolts: 20-25 Nm (15-18 lb-ft).
Exhaust Manifold Nuts: 30-35 Nm (22-26 lb-ft).
Oil Pan Bolts: 10-12 Nm (7-9 lb-ft).
Oil Pump Mounting Bolts: 10-12 Nm (7-9 lb-ft).
Timing Chain Tensioner Bolts: 25-30 Nm (18-22 lb-ft).
Timing Chain Guide Bolts: 20-25 Nm (15-18 lb-ft).
Water Pump Bolts: 20-25 Nm (15-18 lb-ft).
Flywheel / Drive Plate Bolts: 90-100 Nm (66-74 lb-ft).
Engine Mount Bracket Bolts: 55-65 Nm (41-48 lb-ft).
Mazda MPV (LW series, second generation): 1999-2002
model years. The GY-DE was introduced as the sole gasoline V6 engine for the
LW-chassis MPV prior to the 2002 facelift. This application utilized the engine
in a transverse front-wheel-drive configuration with either a four-speed
automatic transmission (Ford 4F27E or Mazda-derived unit depending on production
date). The MPV represented the exclusive application of the GY-DE designation;
following the 2002 facelift, the MPV transitioned to the larger 3.0-liter Ford
Duratec 30-based AJ engine.
Mazda MPV (LW series) export markets: The engine was supplied in North American,
European, and Asian markets with emissions calibrations adjusted to meet
regional standards. All variants maintained the 170 PS (125 kW) power output
with minor variations in torque delivery based on fuel quality and catalytic
converter configuration.
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