Mechanic’s Blog – Bypass Filters

November 24, 2015

Bypass filters: What are they? And why do I need one?

These are questions I hear frequently from customers who see bypass oil filters on the market. Let’s look at what a bypass filter does to get a better idea of why it might benefit the everyday pickup driver.

The stock (OEM) oil filter on any truck will catch damaging particles anywhere from 15-20 microns, which are actually pretty small. For a size reference, the average human hair is about 72 microns in diameter, so 20 microns equals roughly .0008 inches. Pretty small right? But we can do better. Engine bearings and cylinder walls will still be adversely affected by particles as small as 2-5 microns. This isn’t large enough debris that will spin a bearing, or anything like that; but over the course of a couple hundred thousand miles, they make a difference. Why don’t engine manufacturers make stock filters that catch these nearly microscopic particles? Because they want your engine to fail just outside of the warranty! Well not really… Another reason an OEM filter cannot get down to this fine of filtration is because it wouldn’t have enough flow to feed the engine. This is why a Frantz Filter redirects about 4-6% of the oil at a time into the filter itself. It will take some time to filter all of the oil, but within 500 miles of driving we can have the oil cleaner than it came out of the jug.

Extended engine life isn’t the only benefit to a bypass filter, you will also extend the time between oil changes. This is really where a $400 filter system puts money back into your wallet. Modern synthetic oils really don’t break down like their outdated, conventional counterparts. We are able to blend in detergent packages that can withstand thousands and thousands of miles of use. With lab analysis, you can get 50,000 miles out of oil with no problems; remember, we are keeping the oil cleaner than when it was new.

Our media not only takes out particulate contamination, but also things like water and coolant. Even if your head gaskets and oil coolers are in presumably good shape, you can still get trace amounts in the oil from an oil cooler with a slight leak. Maybe not enough for you to notice, but enough to be abrasive inside the engine. Beyond removal of contamination, a bypass filter has cooling properties that help further prevent breakdown of your oil. If you want to protect your engine, extend your oil drain intervals, all while saving money, then you should seriously consider getting a Frantz Filter System.