Have you heard of ‘wet’ timing belts? While many drivers are unfamiliar with this type of engine part, they’re a common component in many cars produced between 2012 and 2021, including some of the most popular makes from top manufacturers like Ford, Peugeot, and many more.
While they were initially introduced to help cut emissions and ensure a smoother ride, they’ve led to serious headaches for many drivers — including total engine failure and eye-watering repair bills.
Photograph and all words from My Motor World; they tell us…
What is a wet timing belt?
A wet timing belt has exactly the same purpose as a dry one: it synchronises the rotation of the crankshaft and camshaft, which in turn ensures the valves open and close at the right time. This keeps the engine running smoothly and efficiently.
The difference comes down to where the belt is housed. A standard timing belt is located outside the engine housing, while a wet belt sits inside it. Another major difference with this type of belt is that it is also constantly lubricated by an oil bath at the bottom of the engine system — hence the name.
Why do some cars have wet timing belts?
The idea is that the oil keeps the belt lubricated, allowing the belt and the engine to run more smoothly. In theory, this reduces noise and improves fuel efficiency. Engineers also hoped that the lubrication would help the belts to last longer than their dry counterparts, reducing the change interval — and associated costs — for the owner. That was the plan, at least!
Why are they controversial?
Wet timing belts are fine when they’re in good condition and working correctly. But once they start to show wear and tear, things can start to go downhill — fast.
Because the rubber belt is in constant contact with the oil, it can cause the belt to degrade more quickly, especially if the wrong type of oil is used. As a result, it may not last as long as the manufacturer’s handbook states it should. This means the belt may fail before the owner of the car even realises there’s an issue.
Wet timing belts can also cause another form of engine failure; one that is unique to this type of belt. As the wet belt gradually suffers from wear and tear over time, small particles come off the belt and are picked up by the oil. Because the belt and the oil bath are inside the engine, these particles are then circulated throughout the rest of the engine system. This can block or damage crucial engine parts and cause blockages in the system that prevent the engine oil from circulating, both of which will lead to engine failure. This means that owners of cars with wet belts have two major engine failure problems to contend with.
A lack of understanding about wet timing belts may be exacerbating the issue. Despite being quite common, many mechanics are much less familiar with them than other types of belts, meaning issues are harder to spot and fix. The knowledge and skill required to deal with the issue can make repairs more difficult and costly, too.
As a result, wet belts have certainly garnered their fair share of detractors in recent years. If you Google ‘wet timing belts’, you won’t have to scroll for long to find forums full of disgruntled car owners lambasting the feature and comparing repair bills.
What are the symptoms?
There may be a few tell-tale signs that a wet engine belt is starting to fail. Symptoms may include:
- Strange noises from the engine bay, such as squealing, grinding, or rattling noises when the engine is switched on or during acceleration.
- The engine light is on.
- Engine oil leaks. This can be a sign that the condition of the belt is deteriorating.
- Low oil pressure.
- The engine misfiring.
- The engine running poorly when idling.
To further complicate things, there won’t necessarily be any obvious signs that the belt is failing or that the oil has become contaminated until it’s too late. Ultimately, the only way to check is for a qualified mechanic to conduct a thorough visual inspection.
Which makes and models are commonly affected?
Ford: EcoBoost and EcoBlue vehicles, including the Fiesta, Puma, Ecosport, C-Max, Focus, Transit, Connect, and B-Max.
Peugeot: 208, 2008, 308, 3008, 5008, Partner.
Citroën: Berlingo, C3, C4, C5 Aircross.
Toyota: Aygo and Proace.
Vauxhall: PureTech engines, including certain Corsa, Astra, Grandland, Crossland and Combo models
Honda: Civic 1.0 litre Turbo
It’s worth noting that not every model of car listed above will have a wet belt, as only models from certain registration years have them. The best way to establish if your vehicle has a wet belt is to look in the owner’s handbook or ask a qualified mechanic to inspect the engine.
What can drivers do to protect their motors?
The good news? While there’s not exactly an easy fix for the problem, there are ways motorists can protect and preserve their engines if they have a wet timing belt.
Regular inspections: Many motorists have complained that their wet belts failed or needed replacing well before the change interval stated by the manufacturer. So, one thing owners of wet timing belt engines can do is check the condition of the belt well before the replacement is due.
Using the right oil: Using the wrong oil will cause the belt to degrade much faster, so getting the right grade and type of engine oil for your car is crucial to the performance and lifespan of the belt. Check the handbook, or contact the manufacturer to get the most up-to-date advice on this.
Replacing the belt before the change is due: Many motorists have found that their wet belts failed before the stated change interval. You can get ahead of this problem by replacing your belt earlier than the manufacturer’s recommended interval, at the first sign of deterioration.
Quote from My Motor World:
“Without regular inspections and proper maintenance, wet timing belts can be an engine killer. To avoid costly repairs, owners of cars with this type of belt really have to be on it with their maintenance schedule. It might be annoying and expensive to keep checking and replacing the timing belt and changing the oil, but it’s still cheaper than a new engine — or even a new car. It’s a case of spending little and often to avoid spiralling costs further down the line.
If you have a wet timing belt, my advice would be to get regular inspections at a garage that’s familiar with them, replace the belt at the first sign of deterioration, and keep that engine oil as clean as possible. And only ever use the exact type of oil that the manufacturer recommends.
It’s hard to imagine what the engineers were thinking when they introduced this feature, given how unpopular it has become. But, it just goes to show that the rigorous testing cars undergo cannot catch every type of fault.
“Finally, a word of warning to owners of cars with the standard timing belts. You may not have the same issues to contend with as a wet belt, but you still don’t want to get complacent, because they can and do fail. So, stick to the change interval given by the manufacturer. Replacing the timing belt is a fairly big job, but you might consider sourcing your own timing belt kit to help reduce the cost of professional repairs at a garage.” – Mark Barclay, Head of Ecommerce at My Motor World
About the brand
My Motor World, famous for its friendly staff and expertise has been a fixture on the British High Street for over 25 years, supplying drivers with a top-quality range of motoring supplies and car parts. Now online, My Motor World offers a wide range of leading brand parts, engine oils and car care products with a free-to-join membership scheme offering extra discounts and perks.