940 / 960

1990-1998 / Sedan / Estate / Sweden

All 940 / 960 problems All workshop issues

Common Engine

Flame trap and PCV system clogged

Symptoms

Engine bogs down, idles rough, struggles to rev, or won't start when hot. You might get excessive crankcase pressure, blowing out seals and pushing oil into the intake.

Cause

The flame trap (a small oil separator box under the intake manifold) clogs with sludge over time. Volvo intended it to be serviced, but most owners forget it exists. Blocked PCV hoses compound the problem.

Fix

Remove the flame trap, disassemble it, and clean thoroughly with carb cleaner and a wire brush.

Replace all PCV hoses, they're cheap and perish quickly.

Check the breather box at the rear of the head while you're at it.

Consider fitting an external oil catch can if you run the car hard.

Do this every 60,000-80,000 km.

Know something we don't?

Owned a Volvo 940 / 960? Share your experience with this issue. What worked, what didn't, costs, tips. Help the community.

Submit an update

// More 940 / 960 problems

Other known issues

Critical Engine

Oil leaks everywhere

You'll find oil pooling under the car, dripping from the valve cover, front and rear main seals, cam seals, or oil cooler lines. The B230 engines (940) and B6304 (960) both weep oil as they age, it's not if, it's when.

Critical Engine

Rough idle, hesitation, or won't start (fuel system issues)

Stumbling acceleration, poor fuel economy, hard starting, or stalling. Sometimes it runs fine cold but misfires when warm. Check engine light may be on or flashing.

Critical Engine

Timing belt and waterpump failures

Catastrophic engine damage if the belt snaps. You'll hear grinding, the engine stops instantly, and you're looking at bent valves or worse. Waterpump failure shows as overheating or coolant leaks from the front of the engine.

Critical Engine

B6304 (960) head gasket and overheating

White smoke from the exhaust, coolant disappearing with no visible leaks, overheating, or rough running. Sometimes you'll see oil in the coolant expansion tank.

Common Cooling System

Radiator, hoses, and expansion tank cracking

Coolant leaks, overheating, or sudden loss of coolant. The plastic expansion tank often cracks at the seams or where hoses attach. Radiator end tanks can split.

Minor Cooling System

Heater core and HVAC issues

No heat, weak heat, or coolant smell in the cabin. Sometimes the blower motor stops working or only runs on certain speeds.

View all 24 940 / 960 problems