Oil filter replacement: how to prevent engine damage

Oil filter replacement: how to prevent engine damage

The importance of replacing engine oil filters with aftermarket products of the same OE quality and specification cannot be understated. Use of replica or counterfeit products can easily cause serious damage, and land car owners with an expensive bill that vehicle warranties will not cover.

Pin point

Take the MAHLE Original OX 171/2D oil filter (pictured below), which is fitted to a wide range of European mainstream models from Peugeot, Ford, Volvo and Mazda. In this filter a patented black plastic mandrel with an O-ring seal is mounted at the end plate of the filter element – known throughout the industry as ‘the MAHLE pin’. When installed, the pin fits precisely into the bore in the filter housing and seals it off.

In order not to violate the filter manufacturer’s patents, some suppliers have attached a large plastic blade to the end plate in their efforts to copy the MAHLE filter insert, but this blade can turn into a destructive weapon as it can get caught when screwing the cover into the housing, making it impossible for the filter insert to rotate.

The consequence of this is that the pin cannot slide along the helix, and the mechanic can no longer rely on any guide to line up the pin exactly with the bore, rendering correct installation an extremely difficult task.

Another problem identified in replica product fitment is that the sharp plastic blade can come dangerously close to the by-pass valve in the housing, causing damage, which will render it useless. As a result, the by-pass valve, which should only be opened for short periods in certain situations, is left permanently open. This lets unfiltered oil circulate without detection continuously through the engine, leading to serious engine damage.

With any luck the rogue pin will not seal the drainage bore properly, resulting in noticeable oil pressure problems, bringing the error to the attention of workshop technicians before any engine damage occurs.

This image shows the patented pin moving along the helix to the draining bore in the housing

Automatic oil draining

MAHLE’s patented pin fulfills other important functions of the oil filter assembly. When unscrewing the cover during a filter change, the pin is pulled out of the bore, clearing it in the filter housing. This ensures that any residual oil in the housing can drain into the oil sump. The complete draining procedure is crucial as it prevents any remaining oil from squirting out of the housing when installing the new filter, while ensuring that the used oil is completely replaced with new oil as far as is possible.

The pin and seal incorporated into the new MAHLE Original filter ensures that the return bore is completely closed again during assemble and during operation. All the engine oil is fed through and cleaned by the filter paper, just as it should be. At the bottom of the filter housing there is a helical guide, similar to a marble run. By tightening the cover, the pin slides through this guide into the bore, where it snaps in place and locks.

The patented design and manufacturing quality of the OX 171/2D – and all MAHLE aftermarket filters – therefore provides the workshop with a guarantee of like-for-like, first-time-fit whenever these vital engine components need to be replaced during servicing and repair.

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