Common Problems with the
2020–2023 Subaru Forester Mk5 (SK)

We've identified 2 known issues that can affect the 2020–2023 Subaru Forester Mk5 (SK). None are considered critical, but they're worth knowing about before you buy.

Known Issues

Serious

Moderate

Minor

The 2020–2023 period has 1 more issue than the Subaru Forester Mk5 (SK) average across all year periods.

All Known Issues

Thermo Control Valve Failure

ModerateCooling System

SK Foresters can trigger multiple warning lights and poor cabin heat when the thermo control valve sticks or fails internally.

Estimated cost: £400–£900Affects: 2019–2023

Typical symptoms

•Engine management warning
•Poor heater performance
•Cooling fan running unexpectedly

What to inspect before you buy

✓Make sure the heater gets hot quickly
✓Scan for stored cooling-system faults
✓Ask whether the valve has already been replaced

Lineartronic CVT Hesitation or Judder

ModerateGearbox & Transmission

Later CVTs are generally better, but neglected fluid changes can still lead to shuddering, hesitation and expensive transmission diagnostics.

Estimated cost: £300–£1,800Affects: 2018–2023Often appears around: 50,000+ miles

Typical symptoms

•Shudder under light throttle
•Delayed response pulling away
•Transmission warning messages

What to inspect before you buy

✓Drive at low speed in traffic-like conditions
✓Check for smooth response on inclines
✓Look for documented CVT servicing rather than verbal assurances

Buying Tips for the 2020 Subaru Forester Mk5 (SK)

✓Check Eyesight warnings clear immediately and ask about any windscreen replacement, as calibration is expensive if done badly.
✓e-Boxer cars should feel smooth in stop-start traffic; any hybrid or charging warning deserves investigation.
✓A quiet CVT and evidence of fluid changes matter more than a glossy dealer stamp book alone.

2019 Subaru Forester Mk5 (SK)