142 / 144 / 145

1966-1974 / Sedan / Estate / Sweden

All 142 / 144 / 145 problems All workshop issues

Critical Cooling System

Thermostat Stuck Open or Closed

Symptoms

Stuck open: engine never reaches normal operating temperature (gauge sits low), poor heater output, high fuel consumption. Stuck closed: rapid overheating, gauge in the red, coolant boiling over.

Cause

Corrosion or mineral buildup in the thermostat housing. Old thermostats lose calibration or seize.

Fix

Test the thermostat by boiling it in a pan of water and checking opening temperature with a thermometer (should open around 82°C).

If suspect, replace it, they're cheap.

Use OEM or quality aftermarket (Wahler, Behr).

Always fit a new gasket or O-ring, and bleed the system afterward.

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Other known issues

Common Cooling System

Radiator Core Leaks and Corrosion

Coolant dripping from the radiator core, overheating, low coolant level without obvious external leaks, white crusty deposits on the radiator.

Common Cooling System

Heater Core Blockage or Leaks

No heat from the vents, sweet smell of coolant in the cabin, wet carpets, fogged windows, low coolant level.

Common Engine

Oil Leaks from Front and Rear Crankshaft Seals

Persistent weeping or pooling of oil beneath the engine, especially at the front timing cover or rear main seal area. You'll see oil misting onto the bellhousing or dripping from the sump.

Common Engine

Worn Valve Guides and Oil Consumption

Blue smoke on startup or deceleration, fouled spark plugs, rising oil consumption between changes (more than half a litre per 1,000 km).

Common Engine

Carburettor Issues (SU or Zenith-Stromberg)

Rough idle, hesitation, stalling when cold, flat spots under acceleration, poor fuel economy, black exhaust smoke.

Critical Engine

Worn Timing Chain or Belt Tensioner

Rattling or slapping noise from the front of the engine, especially on startup or idle. Loss of power, poor running, or misfires if timing has jumped.

View all 21 142 / 144 / 145 problems