Volvo B5252S Specifications
| Engine Model: Volvo B5252S |
| Engine Type: 4-cycle inline 5-cylinder SOHC 10-valve liquid-cooled gasoline |
| Total Displacement: 148.6 cu.in (2.43 L) |
| Rated Engine Power: 142 hp (106 kW) at 5400 rpm |
| Fuel System Type: Multi-point fuel injection |
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The Volvo B5252S is a 2.4-liter, naturally aspirated
five-cylinder gasoline engine from the modular Whiteblock family, produced
during the mid-to-late 1990s. This engine represents the single overhead
camshaft, ten-valve configuration of Volvo’s modular architecture, prioritizing
durability, mechanical simplicity, and low-end torque delivery over high-rpm
power output.
Developed during Volvo’s transition to front-wheel-drive platforms, the B5252S
served as a reliable, tractable powerplant for the 850 series and its
successors. Its all-aluminum construction - comprising both block and cylinder
head - provided significant weight savings compared to earlier Redblock engines
while maintaining the smoothness characteristics inherent to five-cylinder
configurations.
The engine employs a belt-driven single camshaft operating two valves per
cylinder, a design that reduces valvetrain complexity and manufacturing costs
while delivering a broad torque curve well-suited to daily driving applications.
Type: Inline 5-cylinder, gasoline, SOHC, transversely mounted.
Displacement: 2435 cc (148.6 cu.in).
Bore x Stroke: 83.0 mm (3.27 in) x 90.0 mm (3.54 in).
Compression Ratio: 10.0:1.
Valvetrain: Single overhead camshaft driven by a toothed rubber timing belt.
Ten valves total, two per cylinder.
Firing Order: 1-2-4-5-3.
Maximum Power: 144 PS (142 hp / 106 kW) at 5400 rpm.
Maximum Torque: 206 Nm (152 lb-ft) at 3600 rpm.
Aspiration: Naturally aspirated.
Fuel System: Siemens Fenix 5.2 multi-point electronic fuel injection with
sequential injection timing. Ignition System: Distributor-based electronic
ignition with a single ignition coil. The distributor, driven by the exhaust
camshaft position on the cylinder head, routes high-tension voltage to
individual spark plugs through ignition wires. A crankshaft position sensor
provides engine speed and position data to the engine control module. Emission
Standard: Euro 2 compliance with later production variants achieving Euro 3
certification.
The cylinder block is manufactured from aluminum alloy
with cast-in-place iron cylinder liners, a defining characteristic of the
Whiteblock modular engine family. This construction allows the five-cylinder
engine to share manufacturing tooling with four-cylinder and six-cylinder
variants while providing the durability of iron bore surfaces. The block
features a closed-deck design at the cylinder head interface, enhancing
structural rigidity and head gasket sealing.
The crankshaft rotates in five main bearings with a structural bedplate - a
separate aluminum casting bolted to the lower block surface - that adds
stiffness to the bottom end and manages the inherent vibration characteristics
of the five-cylinder configuration. The bedplate incorporates the main bearing
caps as an integral component, ensuring precise alignment of the crankshaft
journals. This modular architecture also includes provisions for balance shafts
in certain applications, though the B5252S operates without them due to the
engine’s inherent smoothness and the naturally aspirated power level.
The cylinder head is cast from aluminum alloy and
houses a single overhead camshaft operating ten valves through hydraulic lash
adjusters and roller finger followers. This valvetrain design eliminates the
need for periodic valve clearance adjustments while reducing friction compared
to direct-acting bucket tappets. The camshaft is supported by five bearings
machined directly into the cylinder head casting. Valve diameters are 40.0 mm
(1.57 in) for intake valves and 34.0 mm (1.34 in) for exhaust valves.
The combustion chambers are of the pent-roof design, optimizing flame
propagation with the centrally positioned spark plug despite the
two-valve-per-cylinder configuration. The intake ports are designed to generate
swirl motion within the cylinders, improving combustion efficiency and low-speed
torque delivery. The single camshaft operates both intake and exhaust valves
through a combination of direct actuation for one set of valves and a short
rocker arm arrangement for the other, depending on the specific valve
arrangement of this SOHC design.
The fuel system utilizes Siemens Fenix 5.2 engine
management, integrating fuel delivery and ignition control within a single
control module. Multi-point fuel injectors are positioned in the intake ports,
delivering fuel sequentially in synchronization with each cylinder’s intake
stroke. The system operates with a returnless fuel line configuration, where a
single line delivers fuel from the tank and a pressure regulator integrated with
the fuel pump module maintains system pressure at 3.0 bar (43.5 psi).
The intake manifold is constructed from composite plastic, reducing weight and
thermal mass while providing smooth airflow passages to each cylinder. A mass
airflow sensor positioned upstream of the throttle body measures incoming air
volume, providing the primary load input for fuel calculation.
The lubrication system employs a gear-type oil pump
driven by the crankshaft and mounted within the timing cover. Oil is drawn
through a pickup tube into the pump, then passed through a full-flow oil filter
before distribution to the main bearings, connecting rods, and camshaft
bearings. The system incorporates an oil pressure relief valve calibrated to
maintain consistent pressure under varying engine speeds and oil temperatures.
Engine Oil Capacity: 5.8 liters (6.1 qt) with filter change. Recommended Oil
Grade: SAE 10W-30 or 5W-30 meeting ACEA A3/B3 or A3/B4 specification.
Semi-synthetic or fully synthetic oils are recommended for extended service
life.
The oil cooler is integrated with the oil filter housing on some vehicle
applications, using engine coolant to stabilize oil temperature. A windage tray
formed into the bedplate separates oil mist from the rotating assembly, reducing
parasitic drag. The oil pan is constructed from stamped steel with a baffled
sump to maintain oil pickup during cornering and braking.
The cooling system utilizes a cross-flow aluminum
radiator with an electric cooling fan controlled by the engine control module. A
belt-driven water pump with a composite impeller circulates coolant through the
engine block, cylinder head, heater core, and radiator. The water pump is driven
by the timing belt, a critical design consideration that links water pump
service to timing belt replacement intervals.
Coolant Capacity: 7.2 liters (7.6 qt) inclusive of the engine, radiator, and
heater circuit. The thermostat is housed in a plastic assembly mounted to the
cylinder head and opens at 87°C (189°F). The cooling system is designed for
long-life coolant conforming to Volvo specification. An expansion tank with a
pressure relief cap accommodates coolant volume changes during thermal cycling.
Timing Drive: The camshaft is driven by a toothed
rubber timing belt with an automatic tensioner maintained by a spring-loaded
mechanism. The belt also drives the water pump, a configuration requiring water
pump replacement during timing belt service. The engine is an interference
design; belt failure results in piston-to-valve contact, causing bent valves and
requiring cylinder head overhaul or replacement.
Crankcase Ventilation: The positive crankcase ventilation system incorporates an
external oil trap - often referred to as the flame trap - mounted on the side of
the engine block. This component separates oil mist from blow-by gases before
they are drawn into the intake manifold. The oil trap contains a series of
passages that allow condensed oil to drain back to the sump. Clogging of this
system is a known maintenance concern, as restricted ventilation leads to
elevated crankcase pressure, causing camshaft seals, crankshaft seals, or the
rear main seal to leak or become displaced.
Exhaust System: A cast iron exhaust manifold with individual runners collects
gases from the five cylinders. The system incorporates a single heated oxygen
sensor positioned upstream of the catalytic converter for closed-loop fuel
control. A three-way catalytic converter reduces hydrocarbon, carbon monoxide,
and nitrogen oxide emissions.
Ignition System: The distributor-based ignition system uses a single coil and
high-tension wires. The distributor cap and rotor require periodic inspection
and replacement due to wear of the contact points and rotor electrode. A
camshaft position sensor integrated with the distributor housing provides
cylinder identification to the engine control module.
Overall Engine Length: 680 mm (26.8 in) from timing
belt cover to flywheel.
Overall Engine Width: 580 mm (22.8 in) measured at the intake manifold.
Overall Engine Height: 710 mm (28.0 in) from oil pan to valve cover.
Dry Weight: 140 kg (309 lb) without ancillary components.
Engine Oil Change Interval: 10,000 km (6,200 mi) or 12
months under normal operating conditions. Severe duty operation requires 5,000
km (3,100 mi) intervals. Oil Filter: Spin-on canister type mounted to the engine
block. Replacement at every oil change. Coolant Replacement: Every 48,000 km
(30,000 mi) or 24 months. Air Filter: Replacement interval of 60,000 km (37,500
mi) under normal conditions.
Timing Belt Replacement Interval: 112,000 km (70,000 mi) or 5 years, whichever
occurs first. Water pump replacement is recommended concurrently with the timing
belt due to its position within the belt drive system and the labor required for
access. Adherence to this interval is critical as the engine is an interference
design. Fuel Filter: In-line replaceable canister type mounted under the
vehicle. Replacement interval of 60,000 km (37,500 mi).
Spark Plugs: Copper-core or platinum-tipped electrodes with a gap of 0.70 to
0.80 mm (0.028 to 0.031 in). Replacement interval of 30,000 km (18,600 mi) for
copper plugs; 60,000 km (37,300 mi) for platinum plugs. Distributor Cap and
Rotor: Inspection interval of 30,000 km (18,600 mi). Replacement is recommended
if carbon tracking, corrosion, or electrode wear is observed.
Ignition Wires: Replacement interval of 60,000 km (37,500 mi) or when signs of
insulation breakdown or high resistance are detected. PCV System Service: The
oil trap and associated hoses require cleaning or replacement at 80,000 km
(50,000 mi) intervals. Symptoms of clogged ventilation include oil leaks from
seals, elevated crankcase pressure, and oil consumption.
Cylinder Head Bolts: Stage one: 30 Nm (22.1 lb-ft).
Cylinder Head Bolts: Stage two: 60 Nm (44.3 lb-ft).
Main Bearing Cap Bolts (M8): 20 Nm (14.8 lb-ft).
Main Bearing Cap Bolts (M10): 40 Nm (29.5 lb-ft).
Connecting Rod Cap Bolts: 25 Nm (18.4 lb-ft).
Camshaft Bearing Cap Bolts: 12 Nm (8.9 lb-ft) for M6 bolts.
Camshaft Bearing Cap Bolts: 21 Nm (15.5 lb-ft) for M8 bolts.
Flywheel Bolts: 70 Nm (51.6 lb-ft).
Intake Manifold Bolts: 20 Nm (14.8 lb-ft).
Exhaust Manifold Nuts: 25 Nm (18.4 lb-ft).
Spark Plugs: 25 Nm (18.4 lb-ft).
Oil Drain Plug: 35 Nm (25.8 lb-ft).
Oil Filter: 20 Nm (14.8 lb-ft).
Water Pump Mounting: 12 Nm (8.9 lb-ft).
Timing Belt Tensioner: 20 Nm (14.8 lb-ft).
Volvo 850: 1993 to 1997 model years. The B5252S was
offered in the 850 2.5 10V designation across European markets, available in
sedan (850 GLT) and estate (850 GLT) body styles. This engine represented the
entry-level five-cylinder option positioned below the 20-valve 2.0-liter and
2.5-liter variants.
Volvo S70: 1997 to 1999. The B5252S powered the S70 2.5 10V sedan in European
and selected export markets, serving as the naturally aspirated alternative to
the turbocharged S70 T5.
Volvo V70 Phase 1: 1997 to 1999. The engine was installed in the V70 2.5 10V
estate variant, offering a balance of torque, fuel efficiency, and load-carrying
capability suited to the wagon’s versatile character.
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