Duramax Oil Capacity Chart by Year and Engine Generation
The 6.6L Duramax diesel holds 10 quarts of oil with a new filter, a figure that has stayed consistent across all six generations built since 2001. That single number hides some real variation though, including a documented case of an owner needing 11 quarts to reach a full reading on the dipstick.
This guide breaks down capacity by every Duramax generation, separates the diesel from the visually similar 6.6L gas engine, and covers the correct oil type and filter so you are not guessing at the pump.
Duramax Oil Capacity
6.6L Diesel, All Generations, LB7 to L5P
Generation Timeline
6.6L Duramax Capacity
Do Not Mix Up These Two Engines
The Duramax diesel takes 10 qt. The similar looking 6.6L L8T gas V8 in the same truck body takes only 8 qt. Confirm badging, fuel filler label, or VIN digit 8 before you pour.
Oil and Filter Quick Reference
| Engine | Oil Type | Filter |
|---|---|---|
| 6.6L Duramax Diesel | 15W-40, or 5W-40 cold | ACDelco PF63 |
| 3.0L Duramax I6 | dexosD 0W-20 | ACDelco PF66 |
| 6.6L L8T Gas | dexos1 5W-30 | ACDelco PF63 |
Fill It Correctly
- Drain fully and replace the filter
- Add roughly 9 qt to start, not the full amount
- Run the engine briefly, then shut it off
- Wait 5 to 10 minutes for oil to settle
- Check the dipstick, top off in small amounts
Duramax Oil Capacity by Generation and Year
Every 6.6L Duramax generation from the LB7 through the current L5P uses the same 10 quart capacity with a new filter installed. Without a filter change, that drops to roughly 9.5 quarts. The table below breaks this down by generation and model year.
| Generation | Model Years | With Filter | Without Filter | Oil Grade |
|---|---|---|---|---|
| LB7 | 2001 to 2004 | 10.0 qt | 9.5 qt | CI-4 or CH-4 |
| LLY | 2004.5 to 2005 | 10.0 qt | 9.5 qt | CI-4 or CH-4 |
| LBZ | 2006 to 2007 | 10.0 qt | 9.5 qt | CJ-4 |
| LMM | 2007.5 to 2010 | 10.0 qt | 9.5 qt | CJ-4 |
| LML | 2011 to 2016 | 10.0 qt | 9.5 qt | CJ-4 or CK-4 |
| L5P | 2017 to present | 10.0 qt | 9.5 qt | CJ-4 or CK-4 |
This applies to the 6.6L Duramax diesel in both GMC Sierra 2500HD and 3500HD and their Chevrolet Silverado HD counterparts. GM’s own dealership TechLink documentation lists the L5P specifically at 9.5 liters, or 10.0 quarts, with a filter change, matching what every generation before it has used.
If you drive a light duty Sierra 1500 or Silverado 1500 with the newer 3.0L Duramax I6, your capacity is different. That engine, badged LM2 through 2022 and LZ0 from 2023 onward, takes 7.0 quarts with a filter according to the same GM documentation. Do not use the 6.6L figures for this engine.
What Changed Across Each Duramax Generation
Six distinct Duramax generations have powered GM heavy duty trucks since 2001. The engineering changed considerably between them, but oil capacity did not.
LB7 Duramax 2001 to 2004
The first Duramax generation ran without a diesel particulate filter and used CI-4 or CH-4 rated oil. It is best known among owners for early fuel injector failures, which GM addressed with an extended warranty rather than a capacity change.
LLY Duramax 2004.5 to 2005
Introduced mid-2004, the LLY added exhaust gas recirculation and a variable geometry Garrett turbocharger. Some 2006 model year trucks still carried the LLY designation before the LBZ took over, but capacity held at the same figure throughout.
LBZ Duramax 2006 to 2007
Many diesel owners consider the LBZ the strongest pre-emissions Duramax, thanks to a higher pressure CP3 injection pump and no diesel exhaust fluid requirement. The oil specification moved to CJ-4, but the quart figure did not change.
LMM Duramax 2007.5 to 2010
The LMM added a diesel particulate filter and ran the longest production stretch of any generation to that point. Mechanically it is close to the LBZ internally, with the biggest differences concentrated in the exhaust and emissions system.
LML Duramax 2011 to 2016
The LML introduced a CP4 injection pump and a stronger internal build, plus support for CK-4 rated oil alongside CJ-4. Capacity again stayed at 10 quarts with a filter.
L5P Duramax 2017 to Present
The current generation is a clean sheet design with a stronger block and higher factory output, up to 470 horsepower and 975 pound feet of torque on later model years. Despite every other change, GM kept the same 10 quart service point.
Why Your Dipstick May Not Match the Spec Sheet
The 10 quart figure assumes a new filter and a completely drained engine. In practice, a small amount of oil stays trapped in the filter housing and internal passages after draining, which is why the without filter figure runs about half a quart lower.
Real world reports go further than that. One 2025 L5P owner on the GM-Trucks.com forum needed 11 quarts to bring the dipstick up to the full mark after a routine oil and filter change, a full quart over the published spec.
Fill in stages rather than dumping the full spec amount at once. Add 9 quarts, run the engine briefly, wait a few minutes for the oil to settle, then check the dipstick and add the rest in smaller increments until it reads full. This protects you from both underfilling and the crankcase pressure problems that come with overfilling.
Do Not Confuse Duramax Diesel With the L8T Gas Engine
GM sells two completely different 6.6 liter V8 engines in the same Silverado 2500HD and Sierra 2500HD body style. One is the Duramax diesel. The other is the L8T gas engine, available since the 2020 model year. They share a displacement on paper and nothing else when it comes to oil.
The L8T takes 8.0 quarts with a filter and runs on dexos1 5W-30 synthetic, according to GM’s own TechLink capacity documentation. Pouring the Duramax diesel’s 10 quart spec into an L8T overfills it by 2 quarts. Going the other direction and underfilling a diesel by 2 quarts is arguably worse, since the diesel runs hotter and works the oil harder under load.
Three ways to confirm which engine you have before you buy oil:
- Check for a Duramax or Duramax Turbo Diesel badge on the hood or fenders, which the L8T does not carry
- Look at the fuel filler neck, since diesel trucks use a larger neck labeled Diesel
- Decode the 8th digit of your VIN, which identifies the exact engine code
Correct Oil Type and Filter for Every Duramax Generation
Oil type matters as much as quantity. For the 6.6L Duramax diesel, GM specifies a full synthetic 15W-40 for standard and warm climate use, dropping to 5W-40 in temperatures below 0 degrees Fahrenheit. The oil must meet API CJ-4 or CK-4 depending on model year, as shown in the generation chart above.
The current factory filter is the ACDelco PF63, listed under GM part number 12735811 for recent L5P applications. This part number has changed more than once. Earlier L5P trucks used part number 12731742, and some very early L5P years used the older PF26 before GM standardized on PF63. In 2024, GM redesigned the PF63 with a slimmer body to fit tighter clearances around the oil cooler, so the physical filter can look different from year to year even under the same part family.
For the 3.0L Duramax I6 in light duty Sierra 1500 and Silverado 1500 trucks, GM specifies dexosD 0W-20 synthetic oil and a PF66 filter, which is a separate part number from the 6.6L filters above.
Always cross reference your exact filter part number against your VIN before ordering, since GM’s supersessions mean the box on the shelf may not match the part number printed in an older forum post.
How to Fill Duramax Oil the Right Way
- Drain the old oil completely and replace the filter, following your specific generation’s torque specs for the drain plug
- Add oil in stages rather than the full amount at once, starting with roughly 9 quarts for the 6.6L or 6.5 quarts for the 3.0L I6
- Start the engine briefly to circulate oil through the new filter, then shut it off
- Wait 5 to 10 minutes for the oil to fully drain back into the pan
- Check the dipstick and add oil in small increments until the level reads full, rather than assuming the spec number is exact for your truck
Know Your Generation Before You Buy Oil
Every 6.6L Duramax generation from the LB7 through the L5P takes the same 10 quarts of oil with a filter, and the 3.0L Duramax I6 takes 7.0 quarts. What changes is not the spec, but the small real world variance you will see at the dipstick and the risk of grabbing the wrong oil entirely if you mix up the diesel with the L8T gas engine next to it on the lot.
Confirm your generation, use the correct filter part number for your build date, and fill in stages instead of trusting a single number from a forum post. If you also own a GMC Sierra and want to round out routine maintenance with the right gear, that is a good next stop.
Duramax Oil Capacity Frequently Asked Questions
How many quarts of oil does a 6.6 Duramax take?
A 6.6L Duramax diesel takes 10 quarts of oil with a new filter installed, a figure that holds true across every generation from the LB7 through the current L5P. Without a filter change, expect closer to 9.5 quarts.
Is Duramax oil capacity the same with and without a filter?
No, the two figures differ by about half a quart. A full service with a new filter takes 10 quarts, while topping off without replacing the filter takes roughly 9.5 quarts.
Does the 3.0 Duramax I6 take the same oil capacity as the 6.6?
No, the 3.0L Duramax I6 found in light duty Sierra 1500 and Silverado 1500 trucks takes 7.0 quarts with a filter, according to GM’s oil capacity documentation, compared to 10 quarts for the 6.6L diesel in HD trucks.
What oil filter fits a 2020 or newer Duramax?
The ACDelco PF63 is the current factory filter for L5P Duramax trucks, though GM has updated the specific part number more than once, most recently in 2024. Always confirm the exact part number against your VIN before ordering.
Why did my Duramax take more oil than the spec says?
Some owners report needing up to 11 quarts to reach a full dipstick reading, a quart over the published 10 quart spec, likely due to oil retained in the filter housing and passages varying by truck. Fill in stages and trust your dipstick over a flat published number.
