Volvo D20, D24 Engine Workshop Manual

A complete service manual for Volvo D20 and D24 diesel engines, including naturally aspirated and turbocharged (D24T) versions. Suitable for use in servicing light commercial vehicles, industrial equipment, generators, and D24-based marine engines.

• Detailed engine structure
• Maintenance regulations
• Step-by-step disassembly and assembly
• Bolt tightening torque and specifications
• Lubrication and cooling system diagrams
• Bosch VE injection pump maintenance
• Adjusting valves and clearances with washers
• Checking and replacing timing belts
• Removing/installing cylinder head, tightening order
• Diagnosing leaks, overheating and loss of compression

• General>>
• Volvo Home Page>>

📌 Installed on cars:

🚘 Passenger cars:

Volvo 240 — modifications D24 and D24T

Volvo 740 / 760 — diesel versions (since 1982)

Volvo 940 (less common) — some markets, in the early 90s

Volvo 260 (in rare diesel versions)

🚐 Commercial vehicles:

Volkswagen LT 28 / LT 31 / LT 35

D24 and D24T were the main diesel engines in these models

Direct cooperation between VW and Volvo

Volkswagen Transporter T3 (Vanagon)

Only in some diesel versions (D24)

⚓ Marine equipment (based on D24):

Volvo Penta MD24 / TAMD40 (partially based on D24T)

Used on yachts, boats and service vessels

1. 🔥 Engine overheating

Symptoms: rapidly rising temperature, boiling, coolant leak

Causes:

• Insufficient cooling efficiency
• Clogged radiator
• Air locks
• Pump wear
• Aluminum cylinder head fatigue

Comment:

These engines are very sensitive to overheating. Even one case of overheating can lead to a breakdown of the cylinder head gasket or cracks in the head.

✅ Solution: install a high-quality pump, timely replacement of antifreeze, temperature control, flush the system.

2. 🧯 Cylinder head gasket failure / cylinder head cracks

Symptoms: white smoke, coolant leak, bubbles in the tank, oily liquid in the expansion tank

Causes:

• Overheating
• Thin cylinder block
• Age and wear of the aluminum head

✅ Solution: grinding the plane, checking for leaks, replacing the gasket with the original, strict adherence to the tightening torque.

3. 🥶 Poor cold start

Symptoms: slow cranking, no catching, smoke

Causes:

• Faulty glow plugs
• Weak compression
• Worn fuel injection pump
• Air leak in the fuel system

✅ Solution: checking the glow plugs, pumping fuel, measuring compression.

4. ⚙️ Unstable operation / loss of power

Symptoms: the engine "troits", does not pull, vibrations

Causes:

• Incorrect fuel injection pump adjustment
• Clogged injectors
• Worn camshaft or tappets
• Air leak

✅ Solution: adjust injection advance, injector ultrasound, check valve clearances.

5. 💨 Heavy smoke (black or white)

Symptoms: black smoke under load, white - during cold start

Causes:

• Rich mixture (incorrect fuel injection pump)
• Faulty injectors
• Problems with compression or turbine (D24T)
• Oil in combustion chamber

✅ Solution: adjust supply, check boost pressure and valve clearances.

6. 🧰 Timing belt / pulley wear

Symptoms: uneven operation, possible breakage

Causes:

• Missed replacements
• Oil on the belt
• Tensioner destruction

✅ Solution: timing belt replacement every 60–80 thousand km, inspection of oil seals.

7. 🛢️ Increased oil consumption / leaks

Symptoms: constant topping up, stains under the car

Causes:

• Worn oil scraper rings
• Oil seal leaks
• Cracks in the cylinder head cover (D24T)
• Breather blows out oil

✅ Solution: compression measurement, crankcase ventilation check, seal inspection.

8. 🔌 Glow plug electrical faults

Symptoms: glow plugs do not heat up, cold start is difficult

Causes:

• Burnt glow relay
• Bad contacts
• Broken wiring

✅ Solution: replace relay, test circuit, install LED control indicator.