LR
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CoolingHigh severity

Engine overheating in traffic or when towing (viscous fan)

Safety or reliability risk. Fix promptly.

Symptoms

Temperature climbs when stationary, crawling off-road or towing, but drops at road speed.

Likely cause

The viscous fan coupling has lost its fluid and no longer locks up when hot, so the fan freewheels.

Suggested fixes

Listed roughly in the order most owners try them.

  1. 1

    Test the viscous coupling

    With the engine fully hot and switched off, the fan should be stiff to turn by hand (use a rolled newspaper, never fingers with the engine running). If it spins freely the coupling is finished.

    Difficulty:
    Easy DIY
    Cost:
    £ (Under about £50 in parts)
  2. 2

    Replace the viscous coupling

    Fit a quality coupling. The coupling has a left-hand or right-hand thread depending on engine, so check before using force.

    Difficulty:
    Moderate DIY
    Cost:
    ££ (About £50 to £300)
  3. 3

    Check the radiator and fan cowl

    A missing cowl or a radiator packed with mud can cause the same symptoms. Flush the radiator fins from the engine side.

    Difficulty:
    Easy DIY
    Cost:
    £ (Under about £50 in parts)

This is general guidance gathered from owner experience and workshop practice, not a substitute for a workshop manual or a qualified mechanic. Costs are rough parts-only guides. Brakes, steering and suspension work affects safety, so if in doubt have it checked professionally.

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