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Rocker Covers: An Integral Engine Component

By autotech-nic on October 12, 2021

A rocker cover (or valve cover) has always been an integral part of the internal combustion engine; protecting the inner moving components of the engine and preventing any debris from entering within. It also ensures the lubricating oil is kept within the engine, which is vital for its operation.

Originally, all rocker covers were made from cast alloy or pressed steel, however – as with all other materials – a lighter and far more adaptable product material was introduced.

As a result, many rocker covers are now manufactured from a reinforced plastic which incorporates additional functions, such as sound insulation, fixing points for additional pipes, hoses and wiring.

In many cases, it also incorporates the engine positive crankcase ventilation valve (PCV). This valve is an essential function of the vehicle’s emission control strategy to direct hydrocarbons from the engine into the induction system.

What leads to failure and replacement?

The originally used polyamide material ages under the influence of constant engine heating, cooling cycles and vibration. As a result, the rocker cover can distort or crack – leading to oil leaks.

This ageing process can lead to cracks in areas of the cover which are often located at positions in the engine compartment that are very difficult to diagnose. A common failure area is around the spark plug or injector locating points, which leads to combustion failure due to the part being saturated in engine oil.

Excess exhaust emissions and the incorrect running of the engine are other reasons why the rocker cover might have to be replaced. This occurs where the PCV is an essential part of the cover itself. Typically, the valve diaphragm fails due to poor oil quality, fuel ingress, short distance driving cycles or cracks in the housing. Consequently, the diaphragm cannot be replaced separately.

Easy installation and increased durability

febi’s rocker covers are made from high quality reinforced polyamide plastic, which are ready to install and come complete with a gasket and fixing screws (where necessary). If the cover has a PCV fitted, the diaphragm is made from fluorosilicone rubber, which is resistant to oil and fuel and can operate over a vast temperature range.

When replacing a rocker cover, you should always ensure that the mating surfaces are clean before fitting the new component. Any vehicle manufacturer fitment recommendations should also be followed.

Note: some rocker cover gaskets require a small amount of sealant applied to the cover at certain points before final installation.

Always tighten any fixings to the recommended tightening torque settings to avoid distorting the rocker cover during replacement.

Benefits at a glance

Leading Offer
• Fast to Market – febi is the first brand to make rocker covers available in the automotive aftermarket!
• An improved range of over 450 rocker covers, suitable for a wide selection of popular vehicle applications in Europe
• Associated products, such as Breather Hoses, are also part of our offer; advisable to replace during every repair.

Premium quality
• All of our rocker covers are of OE-matching quality
• Maximum stability – manufactured using high-quality plastic and fibreglass; following the exact OE specification
• Diaphragms are made of oil and water-resistant Fluorosilicone rubber (FVMQ).

All in one box
• Offering a complete and cost-effective professional repair solution
• Gaskets and screws included, where necessary
• Ventilation valves are included and pre-installed where specified by the vehicle manufacturer.


You can find the complete overview of febi components at:




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Autotechnician is a magazine published nine times a year, delivering essential information to independent garage owners and technicians in the UK. Delivered both digitally and in print, autotechnician provides readers with technical, training, business advice, product and news, allowing our readers to keep up to date with information they need to run and work within a modern workshop.
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