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Oil Filters

























Oil Filters

Who gives a crap about oil filters? What's an oil filter ever done for me?

Oil filters perform a very important function. Bits of metal chip off of various engine parts during the engine's operation. If these bits of metal re-circulate through the oil, these bits will break off other bits of metal. It's erosion. And the erosion occurs under significant pressure. Any erosion that does occur will occur quickly and can compound at exponential rates.

A good oil filter helps prevent this. Poor oil filters shorten a car's life cycle and can even lead to things like a broken bearings (as in bearings that were once circular are now bits and pieces and the piston or crankshaft wobbles uncontrollably), damaged oil pumps and damaged cylinders (replace or re-bore the engine block) to name a few. These sort of problems usually show up in stressed motors sooner than later.

Photos of a camshaft lobe and main bearing from a Chrysler 2.0L sohc.

Photo Top Left: A chip on the top of the crankshaft lobe is clearly visible. This chip was probably caused by natural oil. The natural oil clogged the lash adjusters that resulted in a greater force being applied to the camshaft lobe. The natural oil cannot deal with such forces since it is limited to a compressional strength of about 300psi. The hardened surface of the camshaft is what gave way.

Photo Top Right: The oil filter passed bits of metal through the bypass. These metal pieces went through the oil system and to the frictional surfaces such as the main bearing shown here. A metal flake was ejected from the crankshaft oil line to the main bearing. A deep score was marked on the bearing and to a lesser extent, the crankshaft.

Photo Below: Poor lubrication results in friction and heat that stresses parts to failure. The photo below shows one of the pistons broken between the piston ring grooves. The piston rings also failed and broke.

The owner did not notice any difference in engine behavior as these parts were failing. The "low oil pressure" light came on every once in a while on the instrument cluster. The engine was replaced before it completely failed.


Magnets can help out a good oil filter. Magnets collect ferrous metals (metals that contain iron). Ferrous metal are usually the hardest metals in a motor and can do the most damage left unchecked. Some cars are manufactured with a magnetic drain plug already installed in the oil pan. If the car doesn't already have one, a magnetic drain plug can be purchased an auto parts store such as Pep Boys, Autozone, Napa, O'Reilly's, etc.

An even better option is to use rare earth magnets. The magnetic force of these magnets can cause bodily injury. If that's not a selling point then I don't know what is! FilterMag sells a rare earth magnet that snaps right onto the side of the oil filter. The magnet is so strong that it doesn't need a fastening device to hold it to the car. It's difficult to remove. It's a sure way to collect all the ferrous metals floating around in the engine oil. And all the ferrous metal particles go in the trash with the oil filter when its done.

. .

The only problem with a product like FilterMag is making sure a lube shop gives it back. The oil filter in most cars can be difficult to see or find. If the shop doesn't put the FilterMag on the new oil filter you might not ever know. Or they might not know what it is and break it with an oil filter wrench. It's a bad way to lose $60.

Read more about filter magnets on my Inside an Oil Filter page.


How can an oil filter make a car more efficient?

The answer is pretty straight forward. Get a big one. Get the biggest oil filter that will fit. A bigger oil filter increases the volume of oil available to the engine and increases the filtration surface area. More oil can be filtered at a lower pressure so less oil will go through the bypass unfiltered.

How to find a bigger oil filter

The guy at the parts counter can only tell you what filter is referenced in his database. So you can't trust him to help you get a bigger filter for your car. Get on a web forum focused on your car model and find out if anyone else has put a larger oil filter on their car. Find out what the filter number is. Still no luck? Go to the parts store and plan on spending 20 minutes there examining oil filters. The employees are usually really good at ignoring customers so you can plan on having all that time to yourself, which is what you'll need.


Photo Left: The left filter is referenced in the catalog for a Chrysler/Dodge 2.0L SOHC. The filter on the right is about the same size as what came on the car from the factory in 1995. The filter on the right fits without any modifications. I recommend using the Purolator L14670 filter for all Chrysler/Dodge 2.0L SOHC and DOHC engines.

Photo Right: The two filters from the top. notice the gasket is the same size.

Start by picking out the oil filter referenced by the guy at the desk. Then pick out a bunch of other oil filters in larger boxes. Look at the O-ring gasket. Find a few oil filters that match the O-ring gasket diameter and appear to have a similar threading. Buy all of the ones that potentially fit. When you're under the car later that day, dry-fit the various filters. Keep the largest one that fits. Take back the rest that don't. If they all fail, you'll still have the oil filter the parts guy referenced so the trip won't be a complete loss. Then get on that web forum and submit your findings to your fellow enthusiasts. Let others know how to do what you just did. The larger oil filter helps prevent oil pump grinding in the Chrysler/Dodge 2.4L turbo motors.

Above Photo: The filter on the left is the referenced filter in the catalog for the Chrysler/Dodge 2.4L turbo engine (Neon SRT-4 and PT Cruiser GT). The center filter, L30001 is the preferred filter. Use two filter adapter gaskets to allow the larger filter to thread on (Chrysler part number: 1-04884000AA $4.77 ea). The filter on the right is a Purolator filter made in India. The other two are made in the US. The filter made in India has thicker walls, is built differently, and the paint kept falling off in my hand. It's not going on my car.

Keep clearances in mind. If an oil filter dangles below the oil pan then a speed bump could tear it off causing a complete loss of oil within a few seconds. If the filter rubs on a moving part like an axle, then it's too big. In the case of the test car, a second filter adapter gasket required to push the oil filter adapter out about one eighth of an inch to make room for the larger filter.


Choose an Oil Filter by brand

Purolator, Mobil1, Motorcraft, Mann, and Amsoil.
(and Supertech which is the Walmart brand if you're really on a tight budget)

That's it. It's a short list. That makes it easy to remember.

Purolator Pure One and K&N oil filters are decent. However the media seems dense enough to impede the passage of oil. Those filters are built well.

MANN+HUMMEL & Bosch own Purolator as of 2006. Purolator was previously an ArvinMeritor product and considered to be one of the finest oil filters in the business. MANN+HUMMEL also make oil filters for the German car manufacturers, BMW, Audi, and Porsche. I'm impressed by the construction of the Mann filter. Bosch outsources their oil filters to Champion Labs. And the Bosch filters are awful.

Hastings manufactures Amsoil, Baldwin, and Hastings oil filters. All good stuff.

Champion Labs produces oil filters under a variety of names. Those include Fram, STP, SuperTech, Delphi, Bosch, Mobil1, K&N, AC Delco, and a few others too insignificant to mention. There's a lot of Good, Bad, and Ugly in there.

Cruelty in a Can

Some brands should be avoided like poisonous frogs. Fram, Bosch and WIX make the worst oil filters. Bosch oil filters let everything go through unfiltered. The Delphi and STP filters are identical to the Walmart SuperTech brand for double the price. The Delphi, STP and Walmart oil filters have no bypass valve so everything gets filtered. I don't know if the thing will come apart under severe stress.

Fram oil filters are notoriously awful in construction quality. The end caps are cardboard for crying out loud! Bits of cardboard flake off and bind up in engine parts causing damage. Fram also advertises that their filters are impregnated with PTFE (Teflon). Teflon is a solid plastic that melts together in the oil passages and forms a clot. PTFE is discusses in more detail on the engine oil web page. Fram oil filters are a proven way to ruin Chrysler 2.0L engines.

The WIX oil filters I've seen use undersized filtration media. If the WIX oil filter is cut open, about half of it will be filled by filter material. The rest of the space may be occupied by a plastic insert or who knows what. However, if the filter can is full of media it may be okay.


Oil Filter Tips:

Fill a new oil filter with oil before putting it on. Watch the oil in the filter for 10 seconds. It will start to disappear. The filter media is absorbing the oil. Keep filling the oil filter till it stays full. This will prevent a dry start. If the oil filter is mounted sideways, fill it halfway and expect some oil to pour out as you thread it on.

Run a few drops of oil over the oil filter gasket. This will ease installation and removal.

Always clean off the mounting surfaces before installing the new filter.

Oil drain pans that are completely open at the top are the easiest to use to collect the dripping oil under the car. Then pour the oil into a 5 gallon gas can or equivalent. When the 5 gallon can gets full, take that to a service station to get recycled. The same thing can be done with engine coolant.


Let's review:

Oil filters ensure an engine's longevity.

Shop oil filters by brand: Purolator, Mobil1, Motorcraft, Mann, and Amsoil.

Get the largest oil filter that can fit.


Read more about oil filters on "Inside an Oil Filter."
Oil filters are cut open and examined up close!


Improved Maintenance Topics:
Engine Oil
Oil Filters
Engine Coolant
Ceramic Additive
Air Filters
Spark Plugs
Tire Selection
Wiper Arm Adjustment


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