Quality Auto Repair Services

A wet belt, also known as a belt-in-oil timing belt, is a type of cambelt that runs inside the engine and is lubricated by engine oil. Unlike traditional dry timing belts, wet belts rely heavily on oil quality, oil specification, and service historyto remain reliable.

Wet belts are commonly found in modern engines such as:

• Ford Transit & Transit Custom engines
• Ford 1.0 EcoBoost petrol engines
• PSA / Stellantis 1.2 PureTech petrol engines

A wet belt performs the same job as a traditional timing belt — keeping the engine’s internal components correctly timed — but it runs inside the engine casing and is constantly exposed to oil.

In theory, this design:

• Reduces friction
• Improves fuel efficiency
• Lowers noise

However, in real-world use, wet belts are far more sensitive to incorrect oil, extended service intervals, and poor maintenance.

Over time, the belt material can degrade while running in oil. As this happens, small particles of belt material can contaminate the oil system.

This can lead to:

• Blocked oil pickup
• Reduced oil flow
• Oil pressure warning lights
• Accelerated engine wear
• Complete engine failure in severe cases

In many cases, wet belt failure is not sudden — the damage builds gradually and often goes unnoticed until a serious fault occurs.

Wet belt engines must use the exact oil specification specified by the manufacturer.

Using the wrong oil — even once — can:

• Accelerate belt degradation
• Cause the belt to swell or break down
• Increase the risk of oil system contamination

Manufacturers often quote long replacement intervals, but real-world experience shows that many wet belts can require attention earlier, particularly where:

• Service history is incomplete
• Oil changes were missed or delayed
• Incorrect oil was used
• The vehicle has high mileage

Wet belt engines require:

• Correct timing procedures
• Proper locking tools
• Correct oil and filters
• An understanding of oil system risks

At DR Auto Services, wet belt work is carried out by a Citroën Master Technician with over 10 years’ experience working in a Ford main dealership. This means your engine is worked on by someone who understands these systems in depth — not someone learning on the job.