Practical Automotive Maintenance: Air and Fuel Filters

Back to course

Watch This Course

$99 USD

-OR-

Or 8 easy payments of only $12.38 USD Instant access. Easy checkout. No fees. Learn more

Enroll Now
8 easy payments of only $12.38 USD

Course Access for Life

60 day money back guarantee

Air and Fuel Filters

07.35

00:00	Two of the most overlooked service items for your average driver are the air and fuel filters.
00:05	Although as performance enthusiasts we're generally much more aware of their importance, that doesn't mean we all have a good understanding of the required maintenance or replacement schedules and are often running around with very dirty filters which is a problem.
00:19	They may be small and inexpensive parts, but their role in protecting our engine is absolutely critical.
00:25	Let's start by looking at the air filter which has a simple, but vital job.
00:30	Whenever the engine is running it draws in air and without filtration it'll be pulling in dust, dirt, pollen and all sorts of debris that can cause premature wear if not outright damage.
00:41	The filter element captures all that debris which is great, but after a while it builds up and can affect the performance of the filter, increasing the restriction and resulting in a pressure drop across the filter element which can decrease performance.
00:54	When it comes time to choose a we're faced with two main options.
00:59	OEM filters or aftermarket performance filters.
01:02	OEM filters are built to factory standards and designed specifically for each make and model.
01:07	They strike a balance between efficiency, durability and affordability and they keep our vehicle within warranty requirements if that's a factor.
01:15	Aftermarket filters on the other hand are often marketed towards enthusiasts who want more flow.
01:21	They can be longer lasting, but they usually require cleaning and re-oiling and if not maintained properly they might let more particles through.
01:29	So, how do we know when it's time to replace or clean and re-oil these filters? For an air filter this varies hugely depending on usage.
01:37	For example, if the filter is fitted to an off -road race truck we really need to be replacing or servicing it after only a couple of hundred kilometers of hard use.
01:46	Whereas under normal driving conditions an OEM or aftermarket filter can be fine for over 80 , 000 kilometers.
01:53	With, so much variation in service intervals it's best to inspect a filter for peace of mind.
01:58	Though if it's really bad we might be able to tell that there's an issue without popping the bonnet in the form of engine hesitation and a drop in fuel economy.
02:07	Physically inspecting the filter, whether it's a factory paper filter, drop in panel style or a cone filter, we want to look out for visible dirt between the pleats as well as general darking discoloration.
02:19	If it's a foam filter we should carefully inspect the media for degradation and brittleness.
02:24	Once the foam starts to fall apart it's going to be much worse than having no filter at all as it starts to make its way into the engine.
02:31	While paper filters will simply need to be replaced, aftermarket filters of all kinds are generally, designed to be washed and re-oiled.
02:38	How this is done depends heavily on the manufacturer's recommendations, so it pays to follow the instructions carefully, but the general idea involves removing the filter from the intake system, then clearing out as much of the debris as possible by knocking, lightly brushing and blowing.
02:54	We'll then apply a cleaner, usually a spray foam as recommended by the manufacturer and let it soak for 10 minutes ensuring that it doesn't dry out.
03:03	We can then rinse with low pressure cold water from the inside out.
03:06	We now need to let the filter dry out naturally and we should avoid any temptation to use any type of heat or compressed air as it can warp and damage the material.
03:16	We can then apply the oil which should again be the recommended type as per the manufacturer's instructions.
03:22	We do need to be careful to coat the entire filter, but not overdo it though as too much oil can cause issues if the engine is equipped with a mass airflow sensor.
03:31	Let's now take a look at fuel filters.
03:33	These work on the other side of the equation, screening out rust, dirt and contaminants from the fuel before it reaches delicate components like injectors that can easily become blocked if something foreign makes its way into the system.
03:45	Fuel filters generally last longer than air filters before requiring attention, but should still be periodically checked and replaced as necessary.
03:54	In most vehicles there will be a filter sock located in the tank itself as part of the pump assembly as well as an inline filter meaning it's inserted into the fuel line itself on the way from the tank to the engine.
04:06	Both are fairly easy to access.
04:08	Signs of a failing or clogged fuel filter will generally first show up under high load and include surging, misfires, hesitation or rough running.
04:16	As the problem gets worse we might also notice hard starts, stalling or a warning light and fault code indicating fuel delivery problems.
04:24	Unless the filter uses a see-through housing it can be difficult to know if there's a problem in sight.
04:30	With that said, for the price of a replacement it's worth swapping it out regardless especially as we've already done half the job.
04:36	So, exactly what does that job entail? For the most part replacing a fuel filter is a little more complicated than performing the same job on an air filter.
04:45	Let's start by discussing an inline filter.
04:47	Assuming we're working on an EFI vehicle, the fuel system will be pressurized and that means that we need to relieve the pressure safely before we can remove the filter.
04:56	The easiest way to do this is to locate the fuel pump fuse and pull it.
05:00	The service manual should have that information otherwise a quick google should give us what we're looking for.
05:05	We can then run the car until the fuel system empties itself and the engine shuts down.
05:10	After lifting the car either on a hoist or through a jack and axle stands, we can get underneath and locate the filter.
05:16	It could be anywhere along the fuel line from right next to the fuel tank all the way forward into the engine bay.
05:22	Once it's been found it's a simple case of loosening off the clamps that secure each side of the line, pulling the filter and installing the replacement, ensuring that it's fitted in the correct orientation which is usually signified by an arrow on the filter body indicating the direction of the flow from the pump to the engine.
05:39	Once everything is secure, the fuel pump fuse has been reinstalled and the car is back on the ground, there's no harm in emptying fuel from the inlet side of the filter onto a clean white rag to see any signs of debris which could at least indicate whether the filter was causing an issue.
05:55	If there is one or we could continue investigating once the replacement is fitted.
06:00	As we touched on earlier, most systems also utilize a simple sock filter as part of the fuel pump assembly.
06:06	Generally, it would be unusual to clean or replace this filter unless we're replacing the fuel pump.
06:12	So, this is more of a situation where we'd be diagnosing a fuel delivery issue and had exhausted the more obvious culprits.
06:19	Gaining access to the pump assembly is usually fairly simple and involves removing the rear seats or boot lining and removing the access panel to get to the top of the pump cradle and assembly.
06:29	Again if there's any uncertainty after having a look around, a quick google or a peek at the service manual will point us in the right direction.
06:36	Once that's done, it always pays to replace the sealing rings for the pump assembly if we have them on hand before bolting everything back together and firing up the car for a test drive.
06:46	With that covered, let's summarize.
06:47	Air and fuel filters are small, inexpensive parts, but they play a critical role in protecting an engine by ensuring only clean air and fuel enter the combustion process.
06:58	Air filters should be inspected regularly with service intervals depending on the condition that it's exposed to.
07:03	Paper filters are replaced outright while aftermarket filters are cleaned and re-oiled carefully following the manufacturer's instructions.
07:11	Fuel filters last longer, but can clog over time with symptoms including hard starts, stalling and poor acceleration.
07:18	Older cars often use inline filters that are simple to replace once fuel pressure is relieved.
07:24	Given their importance and relatively low cost, timely inspection and replacement of both air and fuel filters is an essential part of vehicle maintenance.