First Time Changing Mopar Filters on Your RAM 6.7L Cummins? Read This Before You Start

Changing the filters on a RAM 6.7L Cummins for the first time feels intimidating. It's a big diesel engine, the part numbers are confusing, and everyone online seems to assume you already know what you're doing. You don't need to be a mechanic to do this job correctly — but you do need the right information before you start. This guide walks you through every filter on your 6.7L Cummins in plain language, no experience required.

What You're Actually Changing and Why

Your RAM 6.7L Cummins has three filters that need regular attention:

The engine oil filter (5083285AA) — spin-on canister mounted directly on the engine block. Keeps your oil clean. Changed every 7,500 miles under normal use, more often if you tow heavily.

The engine-mounted fuel filter (68157291AA) — NanoNet filter that protects your injectors and high-pressure pump from microscopic contamination. Changed every 15,000 miles.

The chassis-mounted water separator (68436631AA on 2019-2024 trucks, 68197867AB on 2013-2018 trucks) — frame-mounted under the truck on the driver's side. Removes water from your fuel before it reaches the pump. Changed every 15,000 miles, drained every oil change.

All three use genuine american mopar OEM parts. Don't substitute aftermarket on a diesel — the tolerances are too tight and the consequences of filtration failure are too expensive. For a full explanation of why, read our Mopar 5083285AA vs aftermarket breakdown.

Tools You Need Before You Start

Gather everything before you crawl under the truck:

• 28mm deep socket (fits both fuel filters)
• 3/8" or 1/2" ratchet with extension
• Oil filter wrench (optional but helpful on the 5083285AA)
• Drain pan large enough for 3-4 gallons
• Clean shop towels
• Blue nitrile gloves
• Safety glasses
• Flashlight or headlamp
• Jack stands or drive-up ramps (you need clearance to reach the chassis filter)

Do not use a floor jack without jack stands. Ever.

Step 1: Change the Oil Filter (5083285AA)

Where it is: On the driver's side of the engine block, roughly at waist height. Easy to reach without going under the truck.

How to do it:

Warm the engine for 5 minutes, then shut it off and let it cool for 30 minutes. Hot oil burns. Position your drain pan under the filter. Turn the filter counterclockwise by hand — it should break loose without tools. If it's stuck, use an oil filter wrench. Once loose, spin it off slowly and let the oil drain into the pan.

Dip your finger in clean oil and run it around the rubber gasket on the new mopar 5083285AA. This prevents the gasket from sticking or tearing on installation. Thread the new filter on by hand until the gasket contacts the mounting surface, then tighten exactly 3/4 of a turn more. Do not use tools to tighten — hand tight plus 3/4 turn is the correct torque.

The standalone Mopar Oil Filter 5083285AA for 1989-2024 RAM 2500/3500 5.9L & 6.7L Cummins is $24.99 and fits every Cummins-powered RAM ever built.

Step 2: Change the Engine-Mounted Fuel Filter (68157291AA)

Where it is: On top of the engine, clearly visible when you open the hood. Large cylindrical housing with a drain valve at the bottom.

How to do it:

Place your drain pan under the engine. Open the drain valve at the bottom of the housing and let the fuel drain completely — about a half pint. Use your 28mm socket to unscrew the filter housing counterclockwise. Remove the old filter and O-ring. Install the new mopar 68157291AA with a fresh O-ring lubricated with clean diesel fuel. Hand tighten until contact, then 3/4 turn with the socket. Close the drain valve.

Step 3: Change the Chassis-Mounted Water Separator (68436631AA)

Where it is: Driver-side frame rail, under the truck roughly below the driver's seat. You need to be underneath the truck to reach it.

How to do it:

Drain pan underneath. Open the drain valve and drain completely. Disconnect the water-in-fuel sensor electrical connector — squeeze the tab and pull straight out. Use the 28mm socket to unthread the filter counterclockwise. Unscrew the water-in-fuel sensor from the bottom of the old filter and transfer it carefully to the new 68436631AA. Lubricate the new O-ring with clean diesel. Thread on by hand until contact then 3/4 turn. Reconnect the sensor. Close the drain valve.

Step 4: Prime the Fuel System (Most Important Step Beginners Skip)

This is where first-timers make their biggest mistake. After changing the fuel filters you must prime the system before starting the engine — otherwise you run the lift pump dry and risk damaging it.

Cycle the ignition key to the ON position (do not crank the engine) for 30 full seconds. Turn it OFF. Wait 10 seconds. Repeat this cycle 3 times. On the third cycle you'll hear the lift pump working harder as it fills the new filters. Now start the engine. It may run rough for 20-30 seconds as residual air clears — this is normal. Check for leaks at all three filter housings before driving.

Step 5: Check Your Work

With the engine running and warmed up, check every filter housing for leaks. Look for wet spots, dripping fuel, or oil seeping around the gasket. If you see a leak, shut the engine off immediately and retighten the filter 1/4 turn at a time until it stops.

Reset your oil life monitor if your truck has one. Write the mileage on a piece of tape and stick it inside the fuel door — old mechanic trick that keeps you honest about your next service.

Buy Everything Together, Save Time and Shipping

Your first filter change is the perfect time to set yourself up with the complete service kit. The Mopar Fuel & Oil Filter Kit 68157291AA + 68436631AA + 5083285AA for 2019-2024 RAM at $62.99 has every filter you need in one box — no separate orders, no wrong parts, no second trips to the parts store.

For 2013-2018 trucks the Mopar Oil & Fuel Filter Kit 5083285AA + 68197867AB + 68157291AA does the same job at $62.99.

Not sure which generation your truck is? Check our 2013-2018 vs 2019-2024 filter fitment guide — it confirms your exact part numbers in 30 seconds using your VIN.

You've Got This

A RAM 6.7L Cummins filter service is genuinely one of the more accessible DIY jobs on a diesel truck. Clean workspace, right tools, genuine mopar performance OEM filters, and the prime cycle done correctly — that's the whole job. First-timers who follow these steps get it right every time.

Skip the dodge ram oil change coupons at the dealer, save $150 in labor, and do it yourself with confidence.