Cylinder Block and Cylinder Head: Faults, Installation Guide

Construction machinery engine cylinder blocks and cylinder heads are fundamental structural components, enduring extreme pressure, high temperatures, and heavy loads during operation. Their reliability directly impacts equipment uptime, operational efficiency, and long-term costs.

This guide, grounded in practical industry experience, offers a structured, professional overview for fleet operators, maintenance teams, and distributors—covering common faults, troubleshooting steps, installation best practices, and maintenance strategies.

1. Common Faults & Troubleshooting for Cylinder Blocks

As the "backbone" of the engine, cylinder blocks are prone to specific issues under harsh construction conditions. Below is a detailed breakdown of prevalent faults, their causes, and actionable solutions.

1.1 Cylinder Wall Wear or Scoring

Cylinder wall wear is one of the most frequent issues affecting construction machinery engines, often linked to poor lubrication or harsh working environments.

• Key Symptoms: Noticeably increased engine oil consumption (requiring frequent top-ups); reduced cylinder compression, leading to power loss (e.g., sluggish excavation or loading); abnormal engine knocking; and visible scratches on cylinder walls (detectable via endoscopy).

• Main Causes: Use of low-grade engine oil that fails to form a protective lubricating film; dust ingress from unpaved construction sites (mines, infrastructure projects) through the air intake system; and infrequent oil filter replacement, allowing contaminants to circulate.

• Professional Solutions: Replace the worn cylinder block with an OEM-quality, high-wear-resistance model. Recommended options include the 3939313 (compatible with Cummins 6CT engines) and 150102-00538D (suitable for Doosan DE12 engines). These replacements feature precision-bored cylinders, reinforced walls, and durable cast iron or aluminium alloy materials.

• Preventive Measures: Use engine oil that meets the manufacturer’s specifications ; replace oil filters every 250 operating hours; and clean the air filter weekly in dusty environments to block debris.

Aluminium alloy cylinder block

1.2 Cylinder Block Cracking

Cracking is a serious, irreversible fault that typically stems from improper use or maintenance.

• Key Symptoms: Coolant leakage (visible fluid stains beneath the engine); persistent engine overheating (temperature gauge exceeding the normal range); abnormal mechanical noise (vibrations caused by cracks); and unexplained drops in coolant levels (internal seepage from cracks).

• Main Causes: Severe overheating due to cooling system failures (clogged radiators, faulty water pumps); uneven stress from an unclean or uneven mounting surface during installation; impact damage (collisions during transportation or on-site accidents); and prolonged engine overloading beyond design limits.

• Preventive Measures：Replace aging hoses, radiators, or water pumps promptly; avoid prolonged overloading .

2. Common Faults & Troubleshooting for Cylinder Heads

2.1 Cylinder Head Deformation

Deformation often occurs due to thermal stress or improper installation.

• Key Symptoms: Coolant or oil leakage at the cylinder head gasket interface; uneven engine operation (idle jitter, power fluctuations); and failed compression tests (pressure loss in individual cylinders).

• Main Causes: Rapid cooling of an overheated engine ; uneven bolt torque during installation; and impact damage during maintenance or transportation.

• Professional Solutions: For minor deformation (flatness error ≤0.03mm), perform precision grinding to restore surface flatness. For severe cases, replace with an OEM-compatible cylinder head assembly (e.g., models for Komatsu PC200-8 or Caterpillar 320D engines). Always fit a new, high-temperature-resistant cylinder head gasket to ensure a tight seal.

2.2 Valve Seat Sealing Failure

Valve seat issues directly affect combustion efficiency and engine power.

• Key Symptoms: Excessive exhaust smoke (black or blue); reduced engine power (poor combustion from air leakage); abnormal valve noise (tickling sounds during operation); and increased fuel consumption (incomplete combustion).

• Main Causes: Wear from long-term high-temperature operation; carbon deposits (from low-quality fuel or infrequent maintenance); and incorrect valve clearance adjustment.

• Professional Solutions: Dismantle the cylinder head to clean carbon deposits from valves and seats; grind the valve seat to restore sealing contact; replace severely worn valves or seats with OEM-compatible parts; and re-adjust valve clearance per the engine manual.

Cast iron cylinder block

3. Installation Best Practices for Cylinder Blocks & Cylinder Heads

Proper installation is critical to avoiding premature faults. Follow these structured steps for safe, reliable fitting.

3.1 Pre-Installation Preparation

  Start with thorough preparation to ensure a smooth installation process.

 Clean the mounting surfaces of the cylinder block and head thoroughly, removing rust, debris, or old gasket residues.

 Inspect the cylinder block’s cylinder liner for scratches or wear; replace if damaged.

 Check that valve guide bushings and valve stems move smoothly; apply assembly lubricant to reduce friction during fitting.

3.2 Installation Operation Standards

 Adhere to strict operational guidelines to prevent damage.

 Use new, high-quality gaskets (cylinder head gasket, valve cover gasket) and seals—never reuse old ones.

 Tighten cylinder head bolts in a crisscross pattern (from the centre outwards) to distribute pressure evenly.

 For aluminium alloy cylinder heads, retorque bolts after the first test run (once cooled to room temperature) to compensate for thermal expansion.

 Ensure oil passages and coolant channels are unobstructed to prevent overheating or lubrication failure.

3.3 Post-Installation Inspection

Verify installation success with post-fitment checks.

 Conduct a cylinder compression test (standard pressure: 2.5–3.5 MPa for diesel engines).

 Check for coolant or oil leaks after starting the engine.

 Let the engine idle for 30 minutes, monitoring temperature and oil pressure (normal idle oil pressure: 0.2–0.5 MPa).

4. Key Tips for Selecting Replacement Parts 

Choosing the right replacement parts ensures compatibility and reliability.

 (1) Prioritise OEM-quality or OE-compatible parts, verifying part numbers (e.g., 3939313 for Cummins 6CT, 150102-00538D for Doosan DE12) for a perfect fit.

 (2)Select materials based on application: cast iron cylinder blocks for heavy-duty, high-temperature environments; aluminium alloy cylinder heads for lightweight design and efficient heat dissipation.

 (3)Verify product certifications (ISO 9001, CE) to ensure quality and compliance with international standards.

 (4)Partner with suppliers offering after-sales support to resolve installation or quality issues promptly.