Suzuki H25A

Suzuki H25AThe Suzuki H25A is a 2.5 L (2,495 cc, 152.25 cu·in) V6 4-stroke natural aspirated gasoline engine from the Suzuki H-family. The H25A engine was manufactured by Suzuki Motor Corporation from 1996.

The Suzuki H25A engine features an aluminum cylinder block and aluminum cylinder head with two overhead camshafts (DOHC) and four valves per cylinder (24 in total). The cylinder bore is 84.0 mm (3.31 in) and the piston stroke is 75.0 mm (2.95 in). Compression ratio rating is 9.5:1.

The H25A engine is equipped with Sequential Multiport Fuel Injection and electronic ignition system with individual ignition coil for each spark plug.

This engine produced 144 PS (106 kW; 142 HP) at 6,500 rpm of maximum horsepower and 203 N·m (20.7 kg·m, 149.6 ft·lb) at 3,500 rpm of maximum torque.

The breakdown of the engine code is as follows:

  • H – Engine family
  • 25 – 2.5 Liter Displacement

General information

Engine Specifications
Engine codeH25A
LayoutFour stroke, V6
Fuel typeGasoline (petrol)
Displacement2.5 L, 2,495 cm3 (152.25 cu in)
Fuel systemSequential Multiport Fuel Injection
Power adderNone
Power output144 PS (106 kW; 142 HP) at 6,500 rpm
Torque output203 N·m (20.7 kg·m, 149.6 ft·lb) at 3,500 rpm
Firing order1-6-5-4-3-2
Dimensions (L x W x H):

Cylinder block

The Suzuki J20 has an aluminum cylinder block with four bearing support system. It has an 84.0 mm (3.31 in) cylinder bore and 75.0 mm (2.95 in) piston stroke. The engine has two compression and single oil control ring. Compression ratio rating is 9.5:1.

Cylinder block (Suzuki Grang Vitara specs)
Cylinder block alloyAluminum
Compression ratio:9.5:1
Cylinder bore:84.0 mm (3.31 in)
Piston stroke:75.0 mm (2.95 in)
Number of piston rings (compression / oil):2 / 1
Number of main bearings:4
Cylinder inner diameter (standard):84.000-84.050 mm (3.3071-3.309 in)
Piston skirt diameter (standard):83.970-83.990 mm (3.3059-3.3067 in)
Piston pin outer diameter:20.997-21.000 mm (0.8267-0.8268 in)
Piston ring side clearance:Top0.030-0.070 mm (0.0012-0.0028 in)
Second0.020-0.060 mm (0.0008-0.0024 in)
Piston ring end gap:Top0.200-0.350 mm (0.0079-0.0138 in)
Second0.350-0.500 mm (0.0138-0.0197 in)
Oil0.200-0.700 mm (0.0079-0.0276 in)
Crankshaft journal diameter:65.000 mm (2.5591 in)
Crankpin diameter:50.000 mm (1.9685 in)

Cylinder head

The cylinder head is made of aluminum alloy which gives it good cooling efficiency. The engine has dual overhead camshaft design with four valves per cylinder. Intake valves are 30.0 mm (1.1811 in) in diameter, and the exhaust valves are 28.0 mm (1.1024 in). The H25A has self-adjusting hydraulic lifters.

Cylinder head
Valve Arrangement:DOHC, chain drive
Valves:24 (4 valves per cylinder)
Valve head diameter:INTAKE30.0 mm (1.1811 in)
EXHAUST28.0 mm (1.1024 in)
Valve length:INTAKE
Valve stem diameter:INTAKE5.965-5.980 mm (0.2348-0.2354 in)
EXHAUST5.940-5.955 mm (0.2339-0.2344 in)
Valve spring free length: Inner: 36.08 mm (1.4205 in)
Outer: 40.44 mm (1.5921 in)
Camshaft cam height:INTAKE39.445-39.605 mm (1.5529-1.5592 in)
EXHAUST39.428-39.588 mm (1.5523-1.5586 in)
Camshaft journal diameter:25.934-25.955 mm (1.021-1.0218 in)

Head tightening procedure and torque specs:

  • Step 1: 53 Nm; 5.3 kg·m; 38.5 ft·lb
  • Step 2: 84 Nm; 8.4 kg·m; 61.0 ft·lb
  • Step 3: Loosen all bolts to 0 Nm; 0 kg·m; 0 ft·lb
  • Step 4: 53 Nm; 5.3 kg·m; 38.5 ft·lb
  • Step 5: 105 Nm; 10.5 kg·m; 76.0 ft·lb

Maintenance data

Compression pressure
Standard16.0-14.0 kg/cm2 / 250 rpm
Minimun13.0 kg/cm2 / 250 rpm
Compression differential limit between cylinders1.0 kg/cm2 / 250 rpm
Oil system
Recommended engine oil5W-30, 10W-30
Oil type APISG, SH, SJ, SL or SM
Engine oil capacity (Refill capacity)~ 5.5-6.2 L
Oil change interval, km (miles)5,000-10,000 (3,000-6,000)
Oil pressure3.9-4.7 kg/cm2 (390-470 kPa, 55.5-66.8 psi) at 4,000 rpm
Ignition system
Spark plugNGK: BKR6E-11; DENSO: K20PR-U11 or SK16PR11
Spark plug gap1.0-1.1 mm (0.0394-0.0433 in)
Spark plug tightening torque25 N·m (2.5 kg·m, 18.4 ft·lb)

Vehicle applications

ModelYears Produced
Suzuki Escudo / Vitara Wagon / Estate1996–
Suzuki Grand Vitara1998–
Chevrolet Tracker2001-2004
Author: Sergei Wers
About: Co-founder and CEO of a multi-brand auto repair shop (engine repair, chassis repair, body repair and painting) for over 15 years. I have been developing internet sites with technical specifications for more than seven years.

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