Washing Air Filters – The Facts

Washing air filters is a common practice in Australia and around the world, but there are some myths surrounding the practice that we would like to dispel.

Note – We are discussing normal paper air filters in this blog post and not ‘K&N’ / BMC style washable filters. We will have another blog post about these kinds of filters soon.

1. I get more use out of my filter when I wash it – This is true to a certain extent; you will get to use the filter for a longer period of time. But with every wash, you lose around 20% – 60% efficiency and holding capacity, so the filter will block up quicker than if it was brand new. This means there is a tipping point where washing becomes impractical due to the loss in efficiency and holding capacity.

2. I’m covered by the filter’s warranty – You are covered by the filter manufacturer’s warranty for any damage that a faulty filter may cause unless you wash it. Once a Filter has been washed, you are no longer covered under any filter manufacturer’s warranty terms. This will also void any OEM warranty that is applicable at the time. Some filter-washing companies claim to offer a warranty, but we strongly recommend investigating if their policy will cover you in the event of a failure and the destruction of an engine before proceeding with any washing of your air filters.

3. But filters are designed to be washed – Yes & no, In recent years some filter manufacturers have taken washing into account during their design phase and are using more durable paper that can withstand washing but it still voids their warranty terms and they don’t apply this technique to all filters. Finding out if a filter’s media is washable is also problematic, as manufacturers are not normally willing to answer these questions when posed.

4. Are there any filters I can wash? – Yes, Some performance or race filters use a medical gauze as a filter media which is designed to be washed and used as a lifetime filter. These are race-style filters that allow more airflow and, hence, more dust & dirt into your engine even when oiled as per the manufacturer’s instructions. We recommend to always use an OEM or OEM aftermarket filter to ensure no damage occurs to your engine, especially in dusty environments or off-road applications.

5. But I’m saving money when I wash filters – In the short term, possibly, but all it takes is a small cut or hole in the media at some point in the washing process, and you’re going to have big problems on your hands. Even a small amount of dust getting past the filter is enough to ‘dust’ an engine and cause catastrophic failure.  In the grand scheme of things, the costs of new filters are vastly cheaper than having to pay for a new engine.

If you have any other questions relating to washing air filters, drop us an email, and one of our highly trained staff members will get back to you with an answer.