I’m often asked how often a car’s oil filter should be changed and if some filters can go longer than others. But, aren’t all oil filters pretty much the same when it come to how long they last? And what if you are using a synthetic motor oil rated for a longer than factory drain interval? Can the filter go that longer distance?
First let’s explore the basic materials that automotive oil filters are made from so you will understand why some are limited to relatively short change intervals and why better ones can not only filter better but go a lot more miles too.
These days oil filters come in two basic styles, the spin on “can type” filter and the open cartridge type.
The spin on filter has a stamped metal can with a flat base plate crimped onto the bottom of the can. This base plate has a threaded hole in the middle of it for it to be screwed onto the engine and an O-ring or gasket around the parameter of the plate to provide a seal against oil leaking around the plate.
The can holds such components as the filters media which can be made with anything from simple treated paper (cellulose) in the inexpensive oil filters to advanced synthetic NANO fiber media in the best filters. It also contains such things as a pressure relief/anti drain back valve and adhesives or springs to keep it all together.
The cartridge type oil filter is simply the filter media minus the metal can. Instead of screwing onto the side of the engine the filter cartridge is inserted into a well and this well is sealed with a lid or in to a cup that bolts onto the engine.
Regardless of which type of oil filter your car has they both have the same engineering features in common that either restrict or extend the number of miles they can be used without being changed.
Oil filters made from plain pleated paper as a rule should not be used longer than about six months or 7,500 miles. With really inexpensive paper oil filters this might even be pushing it.
Paper simply cannot handle being soaked in hot motor oil for much longer than that without becoming friable and degrading.
Another limiting factor to the life of an oil filter is the pressure relief/anti-drain back valve. This valve is often made from a rubber compound and there is a wide range of qualities where anti-drain back valves are concerned.
Low quality rubber anti-drain back valves have a tendency to harden up when exposed to hot motor oil for a while and become stuck and non-functional meaning your engine could be operating on un-filtered oil or worse, starved for oil under some conditions.
Another major issue that can limit oil filter life is capacity. Simply put how much contaminant the filter media can hold before it loads up, the relief valve is over-run and your engine is operating on un-filtered oil.
Paper filters are also limited in capacity by the very paper that makes them up. Paper tends to load contaminants primarily on the surface of the media and to make matters worse up to 40% of the media in a paper media oil filter has limited flow or is completely blocked and un-flow able reducing its capacity and service life.
To overcome some of the limitations of the paper media any number of filter manufactures have started blending cellulose with glass fiber. This makes the media up to 50% more efficient at removing contaminants from the oil, gives it more capacity and along with a better quality rubber anti-drain back valve, allows these types of oil filters to last as long as six months or about 12,500 miles.
Beyond this though there is now an even better option.
In 2006 Amsoil Inc. introduced a revolutionary new oil filter to the automotive and light truck market.
Since 1972 Amsoil had been making high tech synthetic motor oils capable of up to 25,000 miles or one year drain intervals. Because of the engineering limitations described above though the oil filter still needed to be change at the six month mark, half way through the synthetic oils warranted drain interval.
Because of this Amsoil’s engineers along with industry partners set out to totally re-write the book on oil filters. The result is the Amsoil EAO synthetic NANO fiber oil filter.
The Nano Fiber oil filter eliminates several key limitations found in all earlier filters.
The Nano fiber filter media provides un-believable efficiency being virtually 100% effective at just 15 Microns with unrivaled capacity.
The completely synthetic media is un-effected by long term exposure to hot oil and the rubber anti-drain back valve has been replaced by a high tech silicon compound that stays pliable and working freely without sticking making for an oil filter with a 3 to 5 time longer life span.
When used in conjunction with a long drain full synthetic motor oil the Amsoil synthetic NANO fiber filter has a useful life span of up to 25,000 miles or one year adding a big element of convenience to owning and maintaining your car.
Amsoil Inc. introduced the first full synthetic motor oil in 1972 to meet American petroleum Institute requirements. Today Amsoil is considered the world leader in synthetic lubrication.
By Larry Crider
