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Wet Belt

Wet Belt Replacement
(In-Oil Timing Belt)

Wet belts, also known as in-oil timing belts, are fitted to many modern petrol and diesel engines. Unlike traditional cambelts, a wet belt runs inside the engine and through the engine oil.

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While designed to reduce friction and improve efficiency, wet belts are now widely associated with premature wear, oil contamination, and low oil pressure faults if servicing hasn’t been perfect.

What is a wet belt?

A wet belt is a rubber timing belt that operates inside the engine rather than behind an external cover. It performs the same role as a cambelt — controlling engine timing — but relies heavily on clean, correct-specification engine oil to prevent deterioration.

Wet belts are commonly found in engines such as:

  • Ford EcoBoost

  • PSA PureTech petrol engines

  • Some Vauxhall and VW Group models

Common wet belt problems

As wet belts age, the belt material can begin to break down. This can lead to:

  • Rubber particles contaminating the engine oil

  • Blocked oil pickup pipes

  • Low oil pressure warnings

  • Engine management lights

  • Serious internal engine damage

Many wet belt failures occur without warning and are not detected during routine servicing or an MOT.

Symptoms of a worn wet belt

In some cases, symptoms develop gradually. These may include:

  • Oil pressure warning light

  • Engine running noisily or roughly

  • Loss of power

  • Poor engine performance

However, some vehicles experience no obvious symptoms before a wet belt issue becomes serious.

Are wet belts checked during a service or MOT?

Wet belts are not checked during an MOT and are not visible during a routine service. Because the belt runs inside the engine, inspection requires significant dismantling and cannot be carried out as part of a standard check.​​

Wet belt replacement intervals

Official replacement intervals can be long, but real-world experience shows wet belts can fail much earlier, particularly where oil changes have been lax. Vehicles used mainly for short journeys are also especially vulnerable to in-oil timing belt deterioration.

Ready to arrange a booking?

You can book an MOT and/or Service online. If you require anything else, like a wet belt replacement or diagnostic, or if you aren't exactly sure what your vehicle needs, feel free to contact our friendly team and we will advise you.

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