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Subaru Legacy At Filter O-ring

Culprits behind a Bad Subaru Legacy AT Filter O-Ring

A filter O-ring is a very important part of your Subaru Legacy AT because it allows proper sealing between the filter tube and the transmission body. It maintains the integrity of the fluid and transmission interior. But although the Subaru Legacy AT filter O-ring is made of durable, flexible material, its operation with petroleum products, heat, and pressure variations can take its toll. Take a look at the following symptoms of a bad filter O-ring and the culprits behind them:

Low fuel pressure

The most common cause of low fuel pressure is having a bad O-ring because it allows fuel to leak past itself. As you remove the O-ring from its seat, you may see signs of swelling, extrusion, discoloration, and cracks. The primary reason for such failure is the oxidation of the carbon black or some aggressive chemical attacked its polymer structure.

Fuel spray

Fuel sprays from fuel rails when the O-rings have been poorly installed or the injectors have been poorly seated. Bad installation may result in a flattened out or split O-ring, which loses its ability to properly seal the filter tube and the transmission body. Fuel sprays can cause damages to the engine, so an immediate replacement needs to be done. Keep in mind that utmost care as well as proper lubrication are crucial when installing a new Subaru Legacy AT filter O-ring onto your car.

Exhaust leaks

The contents of the combustion chamber are compressed as the fuel ignites. This is immediately followed by a rapid outward expansion of gases. When there are cracks in the filter O-rings, they allow gas to escape from the engine cylinder, creating noises of leaking gas. The cracks may have been brought about by the high pressure that surrounds the O-rings.

Fuel smell

When the O-rings are improperly seated or damaged, you will be able to smell the strong odor of leaking fuel in the engine compartment. The fuel vapors can even get into the cabin of your car. And when it comes to fuel leaks, you should investigate your car right away because of the hazard it brings. Ignited fuel can cause fires and even explosions in the engine compartment.

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  • Care Tips for Subaru Legacy AT Filter O-Ring 27 February 2013

    The Subaru Legacy AT filter o-ring is a crucial component because it provides a high-pressure seal between the fuel injector and fuel rail and the engine. Abrupt temperature and pressure changes can cause o-rings to shrink, crack, harden, flatten, and generally wear out, even though they are made from highly-durable material. To prolong an o-ring's useful life, you can perform the following maintenance tips to get the most out of them.


    Clean o-ring seat.

    Before placing a new o-ring onto the o-ring seat or groove on the injector, make sure you clean it really well. Put some brake parts cleaner on a soft cloth and wipe away any particle that might be present. Clear away all buildup and oil residue as well. Doing this will allow the o-ring to seat properly, allowing excellent sealing.


    Do not use sharp tools when removing o-rings.

    The use of sharp tools when removing the old o-rings from the o-ring seat may cause damage to the groove itself. When there are nicks or scratches on the groove, leaks may likely result.


    Lubricate the filter o-rings.

    Every time you want to replace the old o-rings, you need to lubricate the new ones to prolong their useful life. Coating them with clean motor oil gives you assurance that the o-ring will not crack, tear, or catch while you install it. Also, lubricating the Subaru Legacy AT filter o-ring before installation will definitely minimize engine damage. Simply dip your finger in motor oil and spread it all over the surface of the o-ring.


    Work clean.

    When working with o-rings, keep in mind that you have to work on a clean workspace with clean hands. This is because even the smallest contaminant like hair, fiber, or grit that might stick to the o-ring or the groove has a high potential to cause tragic leaks.


    Use new o-rings.

    Every time you remove the fuel injectors from the fuel rail or the engine, make sure that you do not reuse the old o-rings. The old ones may no longer sit properly in the o-ring seat and may cause you a number of problems ranging from fuel smells to fuel sprays and low fuel pressure.