Oil is escaping past the seal in the damper. A light film or misting is often only recorded as an advisory; wording about a serious leak means there's enough oil escaping that the damper can no longer be relied on to control the spring.
Wording as it commonly appears on an MOT certificate: “Shock absorber has a serious fluid leak”.
What does it mean?
Oil is escaping past the seal in the damper. A light film or misting is often only recorded as an advisory; wording about a serious leak means there's enough oil escaping that the damper can no longer be relied on to control the spring.
How serious is it?
Usually recorded as: Major. The tester assesses the actual vehicle on the day, so your certificate is what counts.
What normally causes it?
- Age — the seal hardens and the rod picks up pitting that then cuts the seal
- Corrosion or stone chipping on the damper rod
- A failed top mount letting the strut work at a slight angle
What a mechanic would check
Look at how far the oil has run down the body and whether it's wet or just dusty-damp. Then a bounce test on that corner and a comparison with the other side, plus a look at the tyre for the scalloped wear pattern that goes with a damper that's stopped damping.
What might need replacing
- Dampers replaced in pairs across the axle — never one on its own, or the car's handling goes lopsided
- Top mounts and bump stops while it's apart, since they're usually tired by the same age
- Alignment afterwards on a front strut
Can you still drive it?
Failure item. Beyond the certificate, worn dampers noticeably lengthen stopping distances and make the car unsettled over bumps mid-corner — it's one of those faults you only appreciate once it's fixed.
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This is general guidance from a UK mechanic, not a substitute for a physical inspection. Only the tester who inspected your vehicle can confirm what was recorded and why.