Sinister Diesel 13-20 Ram 2500/3500 6.7L Cummins Bypass Oil Filter System
A 6.7L Cummins that tows, idles a lot or runs long oil intervals makes soot, and the factory full-flow filter is built to pass oil fast, not to catch the finest particles. The Sinister Diesel SD-EOF-6.7C-13 adds a second, much finer filter that cleans a small stream of oil all the time the engine runs. It bolts onto 2013-2020 Ram 2500 and 3500 trucks with the 6.7L Cummins and is aimed at owners who want cleaner oil, longer engine life and oil analysis results that back up longer change intervals.
The factory filter sees all of the oil flow, so its media has to stay fairly open. Sinister rates the stock filter at about 20 microns. A bypass system works alongside it: a line taps pressurized oil at the factory oil filter housing, sends a small portion through a dense secondary filter, and returns it to the engine. On this kit the return goes through a billet oil fill cap with a fitting, so the cleaned oil drains straight back into the valve cover. Sinister specifies the AMSOIL EaBP90 bypass filter, rated to catch particles down to 2 microns. Because only a fraction of the oil goes through it, the bypass does not restrict flow to the bearings, and the stock filter stays in place.
A bypass filter will not fix low oil pressure, coolant in the oil or fuel dilution. If you see any of those, find the cause first.
Pull an oil sample at your next change and send it to a lab so you have a baseline for soot, wear metals and viscosity. Check your oil pressure with a gauge, such as our OTC 5610 engine and transmission pressure tester kit, so you know the engine is healthy before adding parts. Then look under the hood for the clearance limits below.
This listing fits 2013-2020 Ram 2500 and 3500 pickups with the 6.7L Cummins. Sinister's own page lists the same part for later trucks too, but our fitment covers 2013-2020. Sinister states the kit will not work on trucks with dual alternators or a dual radiator setup, and some aftermarket grid heater kits need a small trim on one corner of the mounting bracket. If your truck has a second alternator or a work package, send us the year and VIN before you order.
Sinister's guide calls for an oil change at install, so do not refill until the job is done. Remove the dipstick and plastic engine cover, then swap the L-shaped bracket that holds the upper radiator hose to the head for the new filter bracket. Remove the intake box and tube for access, then replace the 1/8 inch NPT plug in the factory filter housing with the supplied 45 degree fitting; a coolant line may need to come off for clearance. Use Teflon tape on the block fittings, route the long line over the head, and connect the short line from the filter block to the new fill cap. Pre-fill the bypass filter with about a quart of oil, top the engine to the factory level, start it, check for leaks and recheck the dipstick. Sinister recommends changing the bypass filter every 15,000 miles or once a year. Note that Sinister has shipped some kits with a WIX SL11042 filter while the AMSOIL filter was short, so check which filter is in your box.
While you are under the hood, two common 6.7 Cummins add-ons are a Fleece PowerFlo in-tank lift pump to keep steady fuel supply to the injection pump and, on 68RFE trucks, a 2013-2018 68RFE thermal bypass valve for the transmission cooler. If the transmission is due for service too, our 68RFE service kit has the fluid and filters, and our 68RFE Ram 2500 fluid change guide covers the procedure.
| Brand | Sinister Diesel |
| Part number | SD-EOF-6.7C-13 |
| Fits | Sinister Diesel 13-20 Ram 2500/3500 6.7L Cummins Bypass Oil Filter System |
| Vehicle fitment | RAM 2500/3500 (2013-2020) |
| Type | Oil Filter Other |
| Condition | New |
| Ships | Same business day (in stock), from the USA |
| Warranty | 1-year |
Yes. The bypass system works alongside the stock full-flow filter. Keep changing the factory filter at every oil change.
Sinister recommends every 15,000 miles or once a year, whichever comes first. If your kit came with the WIX SL11042 filter, Sinister also says about 15,000 miles.
It can, but only with oil analysis to prove the oil is still in spec. Sinister says to follow the engine maker's guidance or your oil supplier's advice.
No. Sinister states the kit does not fit trucks with dual alternators or a dual radiator setup.
No. It taps a factory plug in the oil filter housing, replaces an existing bracket and returns oil through a new fill cap. No cutting or drilling is needed.
Sinister's guide says to pre-fill the bypass filter with about one quart, then top the engine to the factory level and recheck after running it.
