The consequences of using sub-standard oil filters are many and varied and, failure can be catastrophic.

Oil filters appear simple because all of their secrets are hidden inside a plain-looking case. It’s easy to think of oil filters as nothing more than a piece of pleated paper glued inside a metal cylinder, with a rubber sealing ring thrown in for good measure. But oil filters are far more complex than that, and oil filter malfunction or failure can cause, at the least, premature engine wear and oil consumption and, at worst, catastrophic engine failure.

There are a few ways oil filters can malfunction, along with the likely results of such failures. A common problem, especially with poorly-designed oil filters, is clogging of the media. This can result from not changing the oil and filter regularly, but a quality oil filter should have enough capacity to capture and safely hold a substantial amount of contaminants. The consequence of a clogged oil filter is typically the routing of unfiltered oil to critical engine components or, in extreme cases, total oil starvation. In either case, the result is damage to engine bearings and other precision engine parts, greatly shortening engine life.

Quality oil filters incorporate a bypass valve. The role of this valve, is to direct unfiltered oil to engine parts, rather than no oil at all if the filter becomes clogged or if, in particularly cold weather, the oil is too thick to pass through the filtering media until it warms up and thins out. The ‘what if’ here is, ‘what if’ the bypass valve is poorly designed and fails to operate properly? The likely consequence is, as described earlier, oil starvation and serious engine damage.

Even the oil filter housing itself can fail under certain circumstances. Cold start-up with thick oil can produce extraordinary spikes in oil pressure in the filter, and can actually cause the housing to burst – in extreme cases. In such instances, all of the engine oil can be pumped out in as little as a minute. And by the time the driver notices, or perhaps doesn’t even notice, a warning light on the dash, the damage is already done and the engine quite possibly seized and destroyed.

So how does one choose a quality oil filter and avoid all of these “what ifs?”

Choose a filter from a reputable manufacturer and do a little homework on the factors that matter most. The three most important factors to consider are:

  1. Efficiency
  2. Capacity
  3. Reliability

Efficiency is the measure of a filter’s ability to remove small particles from the oil. For instance, Donaldson oil filters have an efficiency of 97.5%, which means they will remove 97.5% of all particles measured microns. A micron is a millionth of a meter, or about one-thousandths of an inch. And our top-of-the-line Donaldson oil filters are 99.9% efficient. The greater the efficiency, the more particles the filter will capture.

Capacity tells you how many contaminants a filter can hold before becoming clogged. Donaldson oil filters have high capacity in grams, which means they can capture and hold significant more contaminants as inferior, standard-size paper. By using the Donaldson oil filter you don’t have to worry about ‘what if’ the filter becomes clogged.

Reliability comes with respected brands. Since most equipment user and professional technicians don’t normally cut open filters to examine their materials and construction, you’ve got to rely on manufacturers who stake their decades of reputation on the design, construction, and performance of components, materials, and engineering that, for the most part, go unseen once they’re assembled. Therefore, motorists, do-it-yourselfers (DIYers), and professional technicians should trust engines to filters made by those who have pioneered innovations.

What happens when choosing to save on an oil filter – Proof by test:

 All tests conducted in ISO certified Lab facilities and conditions

  • Multi-pass test according ISO 4548-12
  • Bubble point test according ISO 2942

Performance tests

Donaldson Original Part: P502458

Chinese Manufacturer: 32A40-00100 (Copy)


Inconsistency in filter design shown in variation of pleats depending on the element. This results automatically in less overall filter capacity.

  • Donaldson sample has a consistent 69 pleats
  • Copy sample has variation between 56 and 62 pleats

Up to 18.5% less pleats in the copy part


 important in the overall filtration of the oil. The lower the efficiency, the more contaminates pass through the filter. These contaminants affect the engine and engine parts in general.

  • Donaldson sample has an average efficiency of 97,39%
  • Copy sample has an average efficiency of 47,35%

+50% of all contaminates go through the copy filter.

>> Imagine your oil has 200 grams of contaminants

With the Donaldson filter, only 5,2 grams passes the filter. Only the smallest particles will pass the media.

With the copy part, 105,3 grams to pass the filter.

20 x more contaminants pass the copy filter


Test with both samples showed the difference in performance clearly. Due to the poor efficiency of the copy filter, the capacity tests failed. Meaning the test bench weren’t able to build up enough pressure to reach final restriction.

Overall the Donaldson elements performed at 99% capacity

 A bubble point test confirmed the poor quality of the copy filter. Bubble point tests are executed to investigate weak spots of the filter. The test confirmed poor quality connection between the media and end cap.

Bypass Valve test

Pressure tests on both elements show a serious issue with the copy filter where the bypass valve opened already under very low pressure. This results in unfiltered oil going back into the engine.

Copy Bypass valve setting performed at only 30% of Donaldson element

Bypass opens much sooner as Donaldson element Filtration efficiency = 0% when bypass is open



Saving on your oil filter during maintenance puts your expensive equipment in serious harm. All engine parts such as injectors, bearings and gears can be affected by the lack of filtration. Filter leakage can occur which put the whole engine at risk and can cause full engine breakdown.

Saving a few euros or dollars can result in massive repair costs afterwards. Don’t cut back on a vital part of healthy engine filtration.