The 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 code | H25A |
| Layout | Four stroke, V6 |
| Fuel type | Gasoline (petrol) |
| Production | 1996- |
| Displacement | 2.5 L, 2,495 cm3 (152.25 cu in) |
| Fuel system | Sequential Multiport Fuel Injection |
| Power adder | None |
| Power output | 144 PS (106 kW; 142 HP) at 6,500 rpm |
| Torque output | 203 N·m (20.7 kg·m, 149.6 ft·lb) at 3,500 rpm |
| Firing order | 1-6-5-4-3-2 |
| Dimensions (L x W x H): | – |
| Weight | – |
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 alloy | Aluminum | |
| 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: | Top | 0.030-0.070 mm (0.0012-0.0028 in) |
| Second | 0.020-0.060 mm (0.0008-0.0024 in) | |
| Piston ring end gap: | Top | 0.200-0.350 mm (0.0079-0.0138 in) |
| Second | 0.350-0.500 mm (0.0138-0.0197 in) | |
| Oil | 0.200-0.700 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: | INTAKE | 30.0 mm (1.1811 in) |
| EXHAUST | 28.0 mm (1.1024 in) | |
| Valve length: | INTAKE | – |
| EXHAUST | – | |
| Valve stem diameter: | INTAKE | 5.965-5.980 mm (0.2348-0.2354 in) |
| EXHAUST | 5.940-5.955 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: | INTAKE | 39.445-39.605 mm (1.5529-1.5592 in) |
| EXHAUST | 39.428-39.588 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 | |
| Standard | 16.0-14.0 kg/cm2 / 250 rpm |
| Minimun | 13.0 kg/cm2 / 250 rpm |
| Compression differential limit between cylinders | 1.0 kg/cm2 / 250 rpm |
| Oil system | |
| Recommended engine oil | 5W-30, 10W-30 |
| Oil type API | SG, 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 pressure | 3.9-4.7 kg/cm2 (390-470 kPa, 55.5-66.8 psi) at 4,000 rpm |
| Ignition system | |
| Spark plug | NGK: BKR6E-11; DENSO: K20PR-U11 or SK16PR11 |
| Spark plug gap | 1.0-1.1 mm (0.0394-0.0433 in) |
| Spark plug tightening torque | 25 N·m (2.5 kg·m, 18.4 ft·lb) |
Vehicle applications
| Model | Years Produced |
| Suzuki Escudo / Vitara Wagon / Estate | 1996– |
| Suzuki Grand Vitara | 1998– |
| Chevrolet Tracker | 2001-2004 |
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