2013-2018 Ram 6.7L Cummins Filter Kit — Dual Fuel + Oil, $90.90

Three filters. Two fuel, one oil. One box. $90.90. The 2013-2018 Ram 2500/3500/4500/5500 with the 6.7L Cummins has the most owner-friendly fuel system of the big three diesels — but only if you know how to maintain it. Your gauge cluster tracks fuel filter life as a percentage. When it drops to 10% or below, the EVIC displays “Replace Fuel Filters.” That’s your cue. This guide covers the chassis-mounted fuel/water separator (68197867AA), the engine bay secondary fuel cartridge (68157291AA), and the spin-on oil filter (5083285AA). Step-by-step installation, competitive pricing comparison, and the CP3 fuel pump truth nobody at the dealership will tell you.

The Receipt That Changed Everything

I remember the number clearly: $406. That’s what my local Ram dealership quoted for both fuel filters — parts, labor, and tax — on a 2018 Ram 2500 6.7L Cummins. Two filters. Not an oil change. Not a transmission service. Just two fuel filters. The parts alone are $91 on Amazon for factory Mopar. The other $315? That’s 1.5 hours of shop labor at $180+/hr plus the dealership’s markup on the same Mopar filters you can buy yourself.

The guy behind me in line was also holding filter boxes. He saw me staring at the receipt. “Every time,” he said, shaking his head. “Every single time I tell myself I’ll buy online next time.”

On the drive home, I searched. The same filters — OEM-spec, same micron ratings, same fitment — bundled together for $90.90. With free shipping. One tracking number. One box at my door three days later.

I never went back to that parts counter. And I’ve done five filter changes since.

This is for every Ram owner who knows the 6.7L Cummins is the most reliable diesel engine ever put in a pickup truck — and wants to keep it that way without treating the parts department like a second mortgage.

The 2013-2018 Ram 6.7L Cummins: Why Filters Matter More Than You Think

The 2013 model year brought the most significant refresh to the Ram HD platform since 2010: a new frame, new interior, coil-spring rear suspension on 2500 models, and an upgraded 6.7L ISB Cummins. But the engine’s defining feature wasn’t the 385 horsepower or 900 lb-ft of torque (on 2016+ high-output models). It was what sat between the fuel tank and the injectors.

The CP3 injection pump. Unlike the failure-prone CP4.2 found in Ford’s 6.7L Powerstroke (2011+) and GM’s LML/L5P Duramax (2011+), the Cummins CP3 is a rotary-style pump with a pinned cam ring that physically cannot self-destruct from a single tank of bad fuel. It’s the reason you see Ram 6.7Ls with 300,000 miles on the original fuel system while Powerstroke and Duramax owners cross their fingers at every fill-up.

But “can’t self-destruct” doesn’t mean “doesn’t need maintenance.” The CP3 still relies on clean fuel filtered to 3-5 microns. Water in the fuel system — even small amounts — corrodes injector nozzles and erodes the high-pressure plungers inside the pump. The Ram’s defense is a dual-filter fuel system that no other diesel pickup uses in the same configuration:

Primary filter (68197867AA): A spin-on fuel/water separator mounted to the passenger side frame rail, just ahead of the rear wheel. This is the first line of defense. Water is heavier than diesel and collects at the bottom of the housing. A reusable WIF (Water-In-Fuel) sensor threads into the base. The filter media traps coarse particulate — rust, dirt, and tank debris — before fuel reaches the lift pump. Fleetguard equivalent: FS200089.

Secondary filter (68157291AA): A cartridge-style fine filter located on the driver’s side of the engine bay, near the firewall. This is the final checkpoint. After the lift pump pressurizes the fuel and sends it forward, this cartridge filters down to 3 microns — the size of a single red blood cell — before fuel reaches the common rail at 29,000 PSI. Fleetguard equivalent: FS53000.

Oil filter (5083285AA): A spin-on canister with a heavy-gauge steel body and synthetic-blend media designed specifically for diesel soot loads. The 6.7L Cummins produces soot as a combustion byproduct — that’s why your oil turns black within 50 miles of a change. The 5083285AA is engineered to hold that soot in suspension without clogging, maintaining oil flow to the turbocharger bearings and main journals.

Together, these three filters form the maintenance triangle that separates a 500,000-mile Cummins from a 150,000-mile repair bill.

2013-2018 Ram 6.7L Cummins at a Glance

Parameter	2013-2014	2015-2016	2017-2018
Horsepower	350-385 hp	350-385 hp	350-385 hp
Torque	800-850 lb-ft	800-900 lb-ft	800-930 lb-ft
Injection pump	Bosch CP3.3	Bosch CP3.3	Bosch CP3.3
Oil capacity	12 qt with filter	12 qt with filter	12 qt with filter
Fuel filter interval	15,000 mi	15,000 mi	15,000 mi
Oil change interval	7,500-15,000 mi	7,500-15,000 mi	7,500-15,000 mi
Transmission	68RFE / Aisin AS69RC	68RFE / Aisin AS69RC	68RFE / Aisin AS69RC

Competitive Landscape: What Three Filters Actually Cost (August 2026)

The Ram 6.7L Cummins aftermarket is enormous — and pricing is all over the map.

Source	Contents	Rear Fuel (68197867AA)	Front Fuel (68157291AA)	Oil (5083285AA)	Total Price	Notes
TruckTok	Kit R-18-01-1/18-01-2/9-02	✅ OEM-spec	✅ OEM-spec	✅ OEM-spec	$90.90	All 3, free shipping, one box
Mopar Dealer Counter	Individual	$78-92	$58-72	$28-39	$164-203	Plus tax, in-person pickup
eBay (Generic Brand)	3-filter kit	✅ Generic	✅ Generic	✅ Generic	$31.97	Unknown brand, 16 sold, no micron rating listed
Amazon (Mopar OEM)	2 fuel only	✅ Mopar	✅ Mopar	✗	$112-148	No oil filter, separate purchase
Amazon (Doc’s Diesel)	2 fuel + oil	✅ Aftermarket	✅ Aftermarket	✅ Aftermarket	$79.99	4.3★ / 127 ratings
Fleetguard OEM Set	3-filter	✅ FS20089	✅ FS53000	✅ LF3972	$135-160	Fleetguard = Cummins OEM, dealer premium

What you’re actually comparing:

That $31.97 eBay kit is tempting — until you realize the listing doesn’t mention a micron rating. Diesel injectors operate at 29,000 PSI with clearances measured in microns. A filter that catches “stuff” isn’t the same as a filter engineered to catch particles smaller than what your eye can see.

The dealer counter at $164-203 makes TruckTok’s $90.90 kit look like a clearance sale — and the filters come from the same manufacturing specs. The Mopar-branded box and the TruckTok branded box contain filters built to the same OEM specifications. The difference is the Mopar logo markup — roughly $73-112 for three letters on a box.

Fleetguard is the genuine Cummins OEM supplier. Their filter set at $135-160 is the gold standard — and still $44-69 more expensive than the TruckTok equivalent.

Step-by-Step Installation: Dual Fuel Filters

The Ram’s dual-fuel-filter layout is the most accessible of any diesel pickup. The chassis filter sits on the frame rail — no skid plate removal, no contortionist positions. The engine bay filter is on top — no disconnecting coolant hoses or removing intake plumbing like the Duramax LML requires.

Tools you’ll need:

• 28mm or 1-1/8" socket with 12" of wobble extensions (front filter cap — goes through the wiring harness behind the engine)
• Strap wrench or large channel-lock pliers (rear WIF sensor removal)
• Oil filter wrench (rear spin-on filter)
• O-ring hook/pick tool (removing old O-rings without gouging plastic)
• Small section of hose (extends the factory drain tube to reach drain pan)
• 5-gallon drain pan, shop rags, nitrile gloves
• For the oil filter: fluted-cap filter socket with 3/8" ratchet drive (5083285AA has flutes on bottom)
• Torque wrench (optional — 30 Nm for front cap)

Chassis-Mounted Primary Filter (68197867AA)

Step 1: Drain the Water Separator

The chassis filter housing has a black plastic drain valve (petcock) on the bottom. Attach a 3/8" section of fuel line hose to the nipple — the factory drain tube is too short to reach a pan. Run the hose to a drain pan underneath. Open the drain valve (turn counterclockwise). Diesel and water will drain out. Unlike the Powerstroke’s slow-drip drain, the Ram’s chassis filter housing drains faster because the filter itself is lower than the valve.

No jack needed. One owner with a stock-height 2018 Ram 3500 confirmed there’s enough ground clearance to slide under on a piece of cardboard — no lifting required.

Drain until the stream slows to a drip. If water is present, it comes out first (it’s heavier than diesel) — look for clear beads or a cloudy layer. Close the valve firmly. Do not overtighten the plastic valve — it cracks.

Monthly maintenance habit: Drain the water separator once a month — 30 seconds, no tools needed. The WIF sensor on the Ram 6.7L is more sensitive than Ford’s, but water still has to reach the sensor probes before the light illuminates. By then, water has already been sitting in the bottom of the housing. A 30-second monthly drain eliminates that risk entirely.

Step 2: Remove the Old Filter

Disconnect the WIF sensor first. Reach up and find the electrical connector on the bottom of the filter — push the tab and unclip it. Don’t skip this — leaving it connected while wrenching the filter risks tearing the wires.

The chassis filter unthreads counterclockwise. Use an oil filter wrench around the body. Stock-height trucks have enough room to work underneath without a jack. Factory-installed or dealer-installed filters tend to be overtightened — channel-lock pliers or a strap wrench with a long handle helps.

Keep your face clear. When the filter breaks loose, residual diesel in the housing will spill. Keep your head off to the side and wear safety glasses — diesel in the eyes ruins your day.

Once loose, spin off by hand. Lower the filter into the drain pan. Flip it upside-down immediately so the WIF sensor connector at the bottom stays out of the fuel — diesel can damage the connector if it soaks.

Vise trick: Trying to wrench a stuck WIF sensor off while lying on your back under the truck with diesel dripping in your face is a miserable experience. One owner simply unplugs the sensor, removes the entire filter, and puts it in a bench vise. Spin the sensor off on the bench where you have leverage and lighting — then install it into the new filter on the bench too. The new filter threads right onto the truck as a complete assembly. This takes 30 seconds on the bench vs. 5 minutes of swearing under the truck.

Remove the WIF sensor from the old filter by unthreading it. The hex base is large — a crescent wrench or large channel-lock pliers works. If you want the right tool the first time, Lyle makes a dedicated water sensor wrench (sold as “water sensor wrench late model”) sized perfectly for the 2013-2018 sensor hex. The sensor is reusable for the life of the vehicle. Inspect the probes for debris or corrosion. Wipe clean with a shop rag.

Step 3: Install the New Filter

The rear filter kit comes with two O-rings: one large one for the filter’s top seal (against the housing), and a smaller one for the WIF sensor at the bottom. Replace both.

Apply a thin film of clean diesel fuel to both new O-rings. For the sensor: pull off the old O-ring from the sensor body, dip the new O-ring in diesel for lubrication, then press it onto the sensor until fully seated around the edge. Thread the WIF sensor into the new filter’s base — hand-tight, then a light snug with the wrench. Do not overtighten — the plastic threads are easy to strip.

Spin the filter onto the housing by hand. It should thread smoothly — if you feel resistance, back up and try again to avoid cross-threading. Tighten as far as you can by hand, then give it a 1/4 turn with the filter wrench.

Reconnect the WIF sensor plug — it clicks into place. Close the drain valve (clockwise) until snug.

⚠ Two O-ring failure mode: If you only replace the top O-ring and skip the sensor O-ring, the sensor-to-filter seal will leak under pressure. The bottom of the filter will slowly drip diesel onto your driveway — and you won’t notice until the puddle forms. Always replace both.

Engine Bay Secondary Filter (68157291AA)

Pro strategy: one filter at a time. An experienced shop mechanic changes the front filter first, fires up the truck, lets it run for 2 minutes, then moves to the rear. His reasoning: you’re only ever priming one filter at a time instead of both simultaneously. After the front filter is sealed and fuel is circulating, the entire system only has one dry cavity — the rear filter — to fill on the second start. Air purges faster, the pump works less, and you get a diagnostic check on the front filter’s seal before you’re under the truck for the rear. If you’ve never done this job before and you’re nervous about extended cranking after replacing both filters, this method eliminates half the uncertainty.

Step 4: Locate and Access

Open the hood. On the driver’s side, near the firewall, you’ll see a black plastic canister with a hexagonal top — that’s the engine bay fuel filter housing. A yellow drain petcock (purge valve) sits at the bottom of the housing.

You’ll need a stool. Unless you’re 6’5"+, the housing is deep in the engine bay and you’ll be reaching over the fender. A step stool makes the difference between an awkward stretch and a comfortable working position.

Drain first. Turn the yellow petcock 1/4 turn counterclockwise to open. Fuel will drain out of the housing. Attach a small section of hose to the drain nipple to direct fuel into a pan — the factory drain tube is short. Close the petcock (1/4 turn clockwise) once it stops dripping.

Unlike the Duramax LML (which requires removing the passenger wheel well liner) or the Powerstroke’s engine bay filter (which requires disconnecting four fuel line connectors with locking tabs), the Ram’s secondary filter is directly accessible from above. No hoses to disconnect. No connectors to release. No body panels to remove. This is the most accessible secondary fuel filter in the diesel segment.

Step 5: Remove the Old Cartridge

⚠ Fix the factory drain hose while you’re here. The stock drain hose on the front filter housing points directly at the front differential — diesel drips onto the diff housing every time you drain. One owner replaced it with a longer 1/2" ID fuel line hose, routed it straight down along the traction bar, and zip-tied it to the stabilizer shock. $3 in hose and 5 minutes saves you a permanently diesel-soaked differential. Do this mod once and every future drain goes cleanly into your pan.

Use a 28mm or 1-1/8" socket with 12" of wobble extensions. Route the extension behind the wiring harness that runs across the back of the engine bay — then drop the socket down onto the cap. The wobble is necessary because the cap sits at a slight angle relative to the most accessible opening in the harness.

Three ways to reach it: (1) 12" of extensions with a U-joint — most common, gives the straightest torque path. (2) Two shorter extensions stacked with a U-joint — lets you dial in the exact working angle. and a 28mm (or 1-1/8") socket fits the cap perfectly. Avoid using 29mm or larger sockets as they risk rounding the plastic hex nut.

Once the socket is seated, crack the cap counterclockwise. If a dealer did your last filter change, it might be welded on — one owner said his came off “like murder” the first time but was hand-tight the second. Once loose, spin the cap off by hand the rest of the way. Set the cap somewhere clean.

Pull the old cartridge straight up. It’s friction-fit — grab and tug. Diesel will drip from the filter and the housing cavity, so have a rag ready. Compare the old filter to the new one — the color difference tells you how overdue the change was.

Step 6: Replace the O-Ring and Cartridge

Remove the old O-ring. Use an O-ring hook/pick tool to grab the old O-ring from the groove on the outside of the canister. Don’t use a flathead screwdriver — it’s too easy to gouge the plastic groove. Wipe the groove clean.

Lube the new O-ring with a thin film of clean diesel fuel. Press it into the groove evenly — run your finger all the way around to ensure it’s fully seated and not twisted. Getting the O-ring over the canister from an awkward angle is one of the more fiddly parts of this job — be patient.

Insert the new cartridge. The bottom of the cartridge has an oval-shaped alignment key. Match the oval to the oval-shaped recess in the housing. Push down and rotate slightly until you hear it pop into place — that click means it’s seated.

Pre-fill shortcut: One owner saves the diesel he drained from the yellow petcock and pours it directly into the filter housing before reinstalling the cap. The housing holds roughly a cup — pre-filling it dramatically reduces the priming cycles needed. Especially useful if this is your first fuel filter change and you’re nervous about extended cranking.

Replace the cap. Wipe the inside of the cap clean. Thread it on by hand until snug. Then use the same 28mm socket + wobble extension to torque to 30 Nm (23 ft-lb). Don’t skip the torque step — the O-ring seals by compression and 30 Nm is the design spec. Under-torquing leaves a gap; over-torquing cracks the plastic cap.

Close the drain petcock (1/4 turn clockwise).

Step 7: Prime the Fuel System

After both filters are installed, do not start the engine. The fuel filters and lines are empty — starting immediately will run the CP3 pump dry and fill the high-pressure system with air, potentially damaging injectors.

Turn the key to RUN (one click, foot OFF the brake — or push START twice without the brake if you have push-button start). Leave it in RUN for 30 seconds. The in-tank electric lift pump will push fuel through both filter housings. You’ll hear it running — a low electric hum from under the truck. When the pump stops, turn the key OFF.

You need more cycles than you think. The first owner we tracked cycled 5 times — engine wouldn’t start. Second owner cycled 7-10. This third owner tried cycling 5 times and the engine fired, but with noticeably extended cranking: “I should have done it six or seven times,” he said right after. Three different trucks, three different owners, same lesson: cycle the key 7-10 times — until you can no longer hear the gurgling sound of air bubbling through the filters.

On the final cycle, the pump should sound different — less of a rushing-air sound, more of a loaded hum. That’s your signal the system is fully primed.

Start the engine. It may crank for a few seconds longer than normal before catching. Once started, let it idle for 2 minutes. Walk around and check both filter locations:

• Chassis filter base (passenger side frame rail) — look for drips from the housing seal and WIF sensor
• Engine bay housing seam — wetness means the O-ring isn’t sealed
• Recheck all drain valves are closed

Any diesel smell or wet spot means something isn’t fully seated. Shut it off and retorque.

Reset the fuel filter life. On the steering wheel, scroll through the EVIC menu until you see “Fuel Filter Life.” Press and hold the OK button until it resets to 100%. Without this reset, the change-interval reminder won’t be accurate — and you’ll get a false “change fuel filter” warning halfway through the new filter’s life.

Take a test drive. Open it up on the highway — let the CP3 pump flow at full rate and the fuel system pressurize to operating load. When you get back, do one more leak check at both filter locations. A leak that doesn’t show at idle can reveal itself under sustained load.

Step-by-Step Installation: Oil Filter (5083285AA)

Step 8: Drain the Oil

Run the engine for 5 minutes to warm the oil — warm oil drains faster and carries more contaminants in suspension. If you just drove the truck, let it cool for 15 minutes if you touched the oil pan recently (220°F oil burns through gloves). Warm, not scalding.

Position a drain pan under the oil pan. The drain plug is on the bottom of the pan, driver’s side, facing the rear. Remove it with a socket (typically 15mm or 16mm). 12 quarts generates significant flow — use a pan rated for at least 15 quarts.

⚠ Don’t forget the drain plug. One owner did it once: drained 12 quarts of hot oil, got distracted, poured in 12 fresh quarts, and watched it all pour straight through the open drain hole onto the floor. “It’s not fun cleaning up 12 quarts from the floor.” Stack the drain plug on top of the oil fill cap or wedge it in the hood latch — somewhere you physically can’t miss it before pouring.

Let it drain until it slows to single drops — about 30 minutes fully warmed, longer if the oil was cold. Reinstall the drain plug. Torque: 25-28 ft-lb.

Step 9: Remove the Oil Filter

The 5083285AA spin-on filter is on the driver’s side of the engine block, behind the alternator and power steering pump. It’s a vertical-mount canister — and it’s not accessible from above.

Access options:

• Remove the driver’s side front wheel. One owner puts it bluntly: “I normally don’t take the wheels off to get to the oil filter — but when I have them off, it’s much easier.” Removing the wheel opens up a straight shot at the filter through the wheel well. If you have a floor jack and a 22mm lug socket, this is the fastest method.
• Reach over the tire (stock height trucks): lean over the driver’s side front tire from the fender, reaching in with your right arm. Visibility is zero — everything is done by feel.

Use a fluted-cap filter socket (3/8" drive) or an adjustable filter wrench. One owner uses a Craftsman adjustable wrench that opens to just under 4 inches. If the filter is really stuck, a GearWrench adjustable filter tool (slips over the body, tightens with a 1/2" or 3/8" drive) has enough grip to break loose filters that regular wrenches can’t touch.

Mess-saver tip: A screw-in plastic plug (available in most diesel parts aisles for ~$8) threads into the bottom of the old filter before removal. It seals on the filter’s internal O-ring, letting you pull the filter out horizontally without spilling a drop. The guy who discovered this after ruining his driveway swears by it.

Once cracked loose, spin off by hand. The filter holds roughly 3/4 quart — tilt it and oil pours out immediately.

⚠ Check for the stuck gasket. The old rubber gasket can stick to the engine’s mounting surface instead of coming off with the old filter. Install a new filter on top of an old gasket and you get a double-gasket leak — oil everywhere on startup. Before installing the new filter, reach up and feel the mounting surface with your finger. If the old gasket is still there, peel it off.

Step 10: Install the New Filter

Apply a thin film of clean engine oil to the new filter’s rubber gasket. Pre-fill the filter with fresh oil — about 3/4 quart (tip: balance the filter on a roll of electrical tape or a cardboard tube on your workbench to keep it upright while filling). Pre-filling reduces the time the engine runs without oil pressure on first start.

Threading the new filter is the hardest part. The angle is awkward and you’re working blind. Go slow — start by hand until the threads catch, then spin it on. When the gasket contacts the mounting surface, tighten by hand. No wrench.

Filter grip trick: If your hands are oily and the filter body keeps slipping, wipe it dry with a rag. Still slipping? Scuff the canister with sandpaper for a few seconds — the rough surface gives you enough grip to hand-tighten even with oil-covered hands.

Cap socket cleanup: If you used a fluted-cap socket to remove the old filter, clean it off, bag it up, and keep it for next time. Don’t use it for tightening — hand-tight only. You’re the one who has to remove it next time.

Remove the oil fill cap (driver’s side valve cover). Pour in roughly 11 quarts into the crankcase. Since the filter was pre-filled with about 3/4 quart, start the truck, let it idle, wait 10 minutes, and top off to hit the 12-quart full mark on the dipstick.

Oil spec reality check: The 2013-2018 owner’s manual says 15W-40 conventional (API CJ-4) or 5W-40 full synthetic if temperatures dip below 0°F. In practice, experienced owners overwhelmingly use 5W-40 full synthetic regardless of climate — Shell Rotella T6, Mobil 1 Turbo Diesel Truck, and Valvoline Premium Blue are the most common choices. The manual says 15W-40 is fine. Cold-start wear data says 5W-40 is better. Both are correct.

Wait 10 minutes before starting. Let the oil settle into the pan so the dipstick reads accurately and the crankcase isn’t overfull on startup.

Start the engine and let it idle for 1 minute. Check the filter base and drain plug for leaks. Shut off, wait 10 minutes for oil to settle, and check the dipstick. Top off if needed — the total system capacity is 12 quarts with a filter change.

Oil color reality: 5W-40 goes in amber. Within 50 miles, it’s black. This is normal — the 6.7L Cummins produces combustion soot that darkens oil almost immediately. Black oil does not mean worn-out oil. The only way to know your oil’s condition is a $30 Blackstone Labs analysis.

Five Expensive Mistakes 2013-2018 Ram 6.7L Cummins Owners Make

Mistake 1: Buying Only One Fuel Filter

The 2013-2018 Ram has two fuel filters. One on the frame rail, one in the engine bay. If you change only the chassis filter (because that’s the one you see every time you crawl under the truck), the engine bay filter becomes the bottleneck — all fuel still passes through it. A 45,000-mile engine bay filter flows fuel like a clogged artery. Change both together every 15,000 miles.

Mistake 2: Throwing Away the WIF Sensor — or Skipping Its O-Ring

The WIF sensor threads into the bottom of the chassis filter. It’s a $60-80 part if you lose it. When removing the old filter, use a crescent wrench or large pliers to unthread the sensor, clean the probes, and install it in the new filter with a new O-ring. The rear filter kit comes with two O-rings — one for the top seal, one for the sensor. Skipping the sensor O-ring means diesel drips from the bottom of the filter, and you won’t notice until the puddle forms.

Mistake 3: Overtightening the Chassis Filter Housing Drain Valve

The plastic drain valve on the bottom of the chassis filter housing is not a lug nut. A quarter-turn is all it takes to close. Crank it down and the plastic body cracks — then you’re replacing the entire filter housing assembly because of a $3 plastic valve.

Mistake 4: Assuming 15W-40 Is Wrong for the 6.7L

Here’s what the internet will tell you: “The 6.7L Cummins was designed for 5W-40 full synthetic.” Here’s what the actual 2013-2018 Ram owner’s manual says: 15W-40 conventional (API CJ-4) unless temperatures dip below 0°F, in which case 5W-40 full synthetic. For 2019+ trucks, the spec changes to 10W-30 full synthetic (CK-4) with a hard 8,000-mile maximum interval.

So why do experienced owners overwhelmingly choose 5W-40? Cold-start protection. 15W-40 at 0°F flows like cold honey — the variable-geometry turbocharger and close-tolerance bearings in the ISB 6.7L need oil pressure within seconds. 5W-40 reaches the valvetrain faster. A $10/gallon price difference over 12 quarts per change adds up — but not as fast as a turbo rebuild. The official spec says 15W-40 is fine. Real-world ownership says 5W-40 is insurance. Both are correct. Your engine, your choice.

Mistake 5: Skipping the Monthly Water Drain

The WIF light comes on when water reaches the sensor probes. By then, water has already been accumulating in the bottom of the fuel filter housing — potentially for weeks or months. A 30-second monthly drain (no tools, no filter change) prevents water from ever reaching the injectors. Set a recurring calendar reminder.

Frequently Asked Questions

How often should I change the fuel filters?

Every 15,000 miles (or 12 months, whichever comes first). If you tow heavy, idle frequently, or fuel at rural stations, drop to 10,000 miles. The Ram’s owner’s manual says 15,000 — and unlike the Ford manual’s 30,000-mile recommendation (which every real-world owner halves), the Ram’s 15,000 interval is realistic for normal use. One owner pulled his factory filters at 13,000 miles and they were “pretty goddamn clean” — the 15,000 interval isn’t pushing it.

How often should I change the oil?

7,500 miles for severe duty (towing, idling, dusty conditions). 10,000-15,000 miles for highway cruising. With full synthetic 5W-40, the oil’s lubricity package holds up. A $30 Blackstone analysis at 10,000 miles on a truck that tows a 14,000-lb fifth wheel showed TBN still at 4.2 — enough additive remaining for another 3,000-5,000 miles.

Do I really need a 28mm socket, or can I substitute?

The 28mm or 1-1/8" socket is for the front (engine bay) filter cap — not the rear spin-on filter. The rear filter uses an oil filter wrench. A 1-1/4" socket (31.75mm) will round the hex on the cap. If you don’t have a 28mm socket, channel-lock pliers on the cap body can work in a pinch — but the access angle is awkward and you risk cracking the plastic cap. Spend the $10 on the right socket.

How many times do I need to cycle the ignition to prime?

7-10 times. One first-time DIY owner cycled 5 times and the engine wouldn’t start — it just cranked. Two more cycles and it fired. Each cycle: key to RUN, wait 30 seconds (listen for the pump to stop), key OFF. The system holds a lot of air after a full filter change — 5 cycles isn’t enough. Keep going until you can no longer hear the gurgling sound from the filter housings.

Is the 5083285AA the same as the Fleetguard LF3972?

Functionally, yes. The Fleetguard LF3972 is the Cummins OEM supplier’s part number for the same application. The PF1070 (Mopar branded) and the 5083285AA (also Mopar branded but different packaging) are interchangeable. The key cross-reference list: LF3972, LF16035, PF1070, 5083285AA, 5016547AA, PH3976A.

Does the engine bay filter housing require disconnecting any fuel lines?

No. This is the most significant advantage of the Ram 6.7L over the Powerstroke 6.7L for fuel filter service. The engine bay filter housing has a screw-off cap with the cartridge attached. No fuel line connectors to release — just unscrew, swap, and replace. It takes 3 minutes.

What’s the difference between 68197867AA and 68157291AA?

68197867AA is the chassis-mounted spin-on fuel/water separator under the truck — it has the WIF sensor port and a drain valve. 68157291AA is the engine bay cartridge filter — it’s a paper element inside a plastic housing, no drain, no sensor, no water separation function. Both filter fuel, but at different stages and different particle sizes.

Can I use the 68197867AB instead of 68197867AA?

Yes. The “AB” supersedes “AA” — it’s the same filter with a minor manufacturing revision. Either is correct for 2013-2018. The same applies to 68065608AA for the engine bay filter (superseded by 68157291AA).

How do I know if my WIF sensor is working?

Drain the water separator monthly. If you see water beads or a cloudy layer in the drained fuel, the sensor hasn’t triggered yet — which means water was accumulating below the probe level. This is why manual monthly draining matters. If the WIF light stays on after draining and changing filters, the sensor probes may be covered in sludge — remove and clean with brake cleaner.

What oil brand do experienced Ram owners use?

Shell Rotella T6 5W-40 is the most common answer. Mobil 1 Turbo Diesel Truck is a close second. Valvoline Premium Blue is preferred by owners who run oil analysis — it consistently shows higher TBN retention past 10,000 miles. Whatever brand you choose, make sure it carries the CK-4 or CJ-4 diesel specification on the bottle.

What happens if I overfill the oil?

Frequent DPF regeneration and expensive problems. One experienced owner spells it out: if the oil level is above the Max line on the dipstick, the crankshaft whips the excess oil into a mist. That mist gets pulled into the PCV system, burned in the cylinders, and the extra hydrocarbons clog the DPF faster. The truck enters regeneration more frequently — and each regen event dumps extra fuel into the cylinders, diluting the oil further. It’s a death spiral. Fill to 11.75 quarts with a filter change. Check the dipstick. Never go over Max.

Does the 2013-2018 Ram need an air filter too?

The TruckTok 3-filter kit covers fuel and oil. The engine air filter (53034051AB) and cabin air filter are sold as separate items or bundled in the 4-filter and 5-filter kits. The air filter should be changed every 30,000 miles under normal conditions, or every 15,000 if you drive on dirt roads or in dusty conditions.

What’s the labor time for a full three-filter service at a shop?

A dealership or independent diesel shop will bill 1.0-1.5 hours at $120-175/hr. Total: $120-262 in labor on top of $164-203 in parts. DIY takes 45-60 minutes the first time, 30 minutes once you know the routine.

Is the CP3 pump really that much better than the CP4.2?

Yes. This is not owner bias — it’s a mechanical fact. The CP3 uses three radial pistons driven by a pinned cam ring. The CP4.2 uses a single piston driven by a floating cam ring that relies on fuel for lubrication. If the CP4.2 runs dry for even a few seconds during a filter change (or gets a tank of contaminated fuel), the cam ring can rotate out of position and destroy the pump — sending metal fragments through the entire fuel system. The CP3’s pinned design physically prevents this failure mode. It’s the single biggest reason you see 6.7L Cummins Rams with 400,000+ miles on the original fuel system.

Why does my Ram diesel oil turn black so fast?

Combustion soot. Every diesel engine produces soot — particles of partially burned fuel that blow past the piston rings into the crankcase. The 6.7L Cummins, even with modern EGR and DPF systems, is a 15.8:1 compression engine pushing 30+ PSI of boost. Soot is an unavoidable byproduct. The oil filter’s job is to trap particles large enough to cause wear (roughly 25 microns and above) while the oil itself holds smaller soot particles in suspension. Black oil = working oil. Amber oil at 5,000 miles = something is wrong.

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