Do filters get the credit they deserve?

Do filters get the credit and attention that they deserve? To find out, MANN+HUMMEL Product and Marketing Manager – Aftermarket, Gary Winslow, gives a candid opinion and takes you through the importance of each filter.

Filtration is often overlooked on a vehicle. To many, filters can be a consumable, throw-away item that is out of sight, out of mind. Subsequently, claims of OE specification are often banded about, irrespective of any actual credentials to back this up. ‘Fit and forget’ is often a very apt opinion of filters by some technicians.

Sure, filters can be relatively inexpensive as part of the whole engine service, but they can be a real deal-breaker – and engine breaker! – if low-cost, low- quality items are used to cut corners.

Once the vehicle, be it a car, lorry or tractor leaves the workshop, it can be hard to justify spending a little more on a proven, OE quality product. But when something goes wrong…the whole vehicle comes to a grinding halt, often with very expensive repercussions and possible loss of reputation to the workshop and technician.

So, is the filter really fit and forget? Imagine selling a filter without the manufacturing expertise from the likes of MANN-FILTER, for example… Oil loss, blown engine? Fuel starvation, stalled car? Low power, error codes? Misted windows, stale, stuffy air in the cabin? Not worth it, or the reputational damage. Filters then: probably the hardest working component of the engine – but not that you can see it!

First, the oil filter. This filters the oil in an average car sump approximately 240 times an hour – for context, on a 200-mile trip, circa 5,000 litres of oil is filtered! At modern service intervals, upwards of 300,000 litres of oil can be cleaned by the filter. That’s a lot of oil for a small filter.

Fuel filters: As fuel is recirculated by modern injection systems, a 50-60L tank of fuel is cleaned around twice per hour. This equates to the fuel filter cleaning approximately 12 times more fuel than the engine is consuming. With injection systems now very fine and increasingly sensitive to water in the fuel, many OE quality fuel filters will also double-up and filter water from the fuel and contaminant. Twice the work for this filter.

Air filters are often the poor relation and not replaced at ‘interim’ services but can ‘breathe’ in around 2,500 litres of air per minute. For context this is around 40 litres of air a second, and over a 200- mile journey around two million litres of air! Coupled with wet winter conditions, and air-flow meters becoming very sensitive to any disruption in airflow, the air filter is critical.

And lastly, cabin filters. Since COVID, many VMs are now seeing this filter as the main, key filter – why? It protects the driver and the passengers, the most important operating part of the whole car, lorry or machine. With a modern, high-specification cabin filter now not just filtering pollen but also harmful gases – nitrogen oxide, sulphur dioxide, ozone – and now stopping allergens and bacteria from entering the cabin, the modern cabin filter is a must-fit.