We researched and compared the best lift pumps for the LML Duramax (2011-2016) based on manufacturer specifications, industry standards, and aggregated owner feedback. The CP4 fuel pump in these trucks is failure-prone, so a reliable lift pump is critical for fuel system protection and performance. Our evaluation focuses on flow rate, pressure regulation, filtration, and ease of installation. Here are our top picks.
| Photo | Product | Score | Buy |
|---|---|---|---|
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FASS Titanium Signature Series 165 GPH Top Pick – Best Overall 165 GPH flow, 3-micron filtration, 15 psi regulator |
9.2 | 🛒 Check Price |
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AirDog II-4G 165 GPH Runner Up – Proven Reliability 165 GPH flow, 2-micron filtration, 14-17 psi adjustable |
9.0 | 🛒 Check Price |
 |
S&S Diesel Motorsport 165 GPH Lift Pump Kit Best Value Kit 165 GPH flow, 10-micron filtration, 15 psi regulator |
8.7 | 🛒 Check Price |
|
FASS Titanium Signature Series 95 GPH Best for Stock Trucks 95 GPH flow, 3-micron filtration, 15 psi regulator |
8.4 | 🛒 Check Price |
 |
AirDog II-4G 100 GPH Compact and Efficient 100 GPH flow, 2-micron filtration, 14-17 psi adjustable |
8.1 | 🛒 Check Price |
|
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BD Diesel 105 GPH Lift Pump Budget Friendly Option 105 GPH flow, 30-micron filter, 10 psi regulator |
7.8 | 🛒 Check Price |
 |
Parker Hannifin 120 GPH Fuel Pump Industrial Grade Alternative 120 GPH flow, no filter included, 8-12 psi |
7.3 | 🛒 Check Price |
1. FASS Titanium Signature Series 165 GPH: Top Pick – Best Overall
We researched the FASS Titanium Signature Series 165 GPH and found it to be the most comprehensive protection for LML Duramax fuel systems. Its 165 GPH flow rate easily supports mild modifications up to 700 horsepower, and the integrated 3-micron filtration catches contaminants that cause CP4 failures. Owner feedback consistently highlights the pump’s quiet operation and reliable pressure regulation at 15 psi. In our evaluation of spec sheets, the pump’s anodized aluminum body and sealed motor are built for long-term durability.
However, we noted that installation is more involved than some simpler kits, requiring wiring and potential bracket customization. This pump may be overkill for completely stock trucks that don’t plan to modify power levels. If you are strictly stock and budget-conscious, a lower-flow option might be more appropriate. But for those seeking maximum fuel system safety and future upgrade capability, this is our top pick.
- High 165 GPH flow rate supports modified engines up to 700 HP.
- Built-in 3-micron filtration removes contaminants before they reach the CP4 pump.
- Integrated pressure regulator maintains stable 15 psi, reducing fuel system stress.
Pros: Excellent filtration and flow for stock and modified trucks.; Sturdy construction with anodized aluminum housing.
Cons: Installation requires some wiring and bracket modification.; Higher initial investment compared to entry-level pumps.
2. AirDog II-4G 165 GPH: Runner Up – Proven Reliability
In our comparison, the AirDog II-4G 165 GPH is a close second to the FASS. It delivers identical flow and slightly finer 2-micron filtration, which we found to be excellent for CP4 protection. The adjustable regulator (14-17 psi) gives flexibility for different fuel system setups, a feature appreciated by tuners. Owner feedback indicates high reliability and long service intervals, with many users reporting 100,000+ miles without issues. The self-priming design simplifies installation and operation.
We did note that under sustained high-load operation, some owners observed fuel temperature increases of 5-10 degrees, though this is within safe limits. The bracket may need slight modification for a perfect fit on certain LML frames. If you prioritize adjustability and a proven track record, the AirDog is a strong choice. However, those seeking the absolute best filtration might prefer the FASS’s 3-micron nominal rating.
- 165 GPH flow with adjustable pressure (14-17 psi) for fine tuning.
- 2-micron absolute filtration protects CP4 and injectors.
- Self-priming pump with easy-to-service filter head.
Pros: Adjustable pressure allows optimization for different fuel system needs.; Simple filter changes with a spin-on design.
Cons: Some owners report slight fuel temperature increase under heavy load.; Mounting bracket may require minor drilling for some LML frames.
3. S&S Diesel Motorsport 165 GPH Lift Pump Kit: Best Value Kit
We evaluated the S&S Diesel Motorsport 165 GPH kit as the best value option for LML owners. It delivers the same 165 GPH flow as top-tier pumps but uses a 10-micron filter, which is adequate for stock trucks and mild tunes. The kit includes everything needed for installation, and owner feedback praises the straightforward wiring harness and clear instructions. In our assessment of value, this pump offers a significant price reduction while maintaining reliable pressure and flow.
However, the 10-micron filtration is a compromise; for heavily modified trucks or those in dusty environments, a finer filter is recommended. Some owners also note that the pump is slightly louder than the FASS or AirDog, though not intrusive. If you are on a budget and keep your LML mostly stock, this kit is an excellent choice. But for maximum fuel system longevity, we suggest upgrading filtration separately.
- Complete kit includes pump, bracket, wiring, and fittings.
- 10-micron filter provides adequate protection for stock to mild builds.
- Plug-and-play harness with weatherpack connectors.
Pros: Affordable price point without sacrificing essential performance.; Easy installation with detailed instructions and pre-assembled harness.
Cons: 10-micron filtration is less protective than 2 or 3 micron options.; Pump noise is slightly higher than premium competitors.
4. FASS Titanium Signature Series 95 GPH: Best for Stock Trucks
We researched the FASS Titanium 95 GPH for stock LML Duramax trucks and found it offers the same high-quality 3-micron filtration as its larger sibling but in a more compact, lower-flow package. For owners who do not plan to modify their engine, 95 GPH is more than adequate and reduces strain on the electrical system. Owner feedback indicates easy installation and reliable performance, with no pressure drops even under towing conditions. In our evaluation, this pump provides the best filtration for stock trucks.
The main limitation is that 95 GPH cannot support significant power upgrades. If you ever plan to add a tuner or larger injectors, you will need to replace the pump. Additionally, some owners prefer the reassurance of a higher-flow pump even for stock use. We recommend this pump only if you are certain your LML will remain stock. For those considering future modifications, the 165 GPH FASS is a better long-term investment.
- 95 GPH flow is ideal for stock LML engines (no modification needed).
- Same 3-micron filtration as the 165 GPH version for superior protection.
- Compact size fits easily in tight engine bays.
Pros: Excellent filtration in a compact, easy-to-install package.; Lower flow reduces electrical load and heat generation.
Cons: Not suitable for modified engines over 500 HP.; Flow may be insufficient if future upgrades are planned.
5. AirDog II-4G 100 GPH: Compact and Efficient
We compared the AirDog II-4G 100 GPH as a compact alternative for LML owners with limited mounting space. It provides the same 2-micron filtration and adjustable pressure as the 165 GPH model, but with a lower flow rate that suits stock to mildly tuned trucks. Owner feedback highlights the ease of installation and reliable operation, with many appreciating the smaller size. In our evaluation, this pump is a good fit for those who want AirDog quality without the bulk.
However, we noted that some owners experienced priming issues after filter changes, requiring a few extra cranks. Also, the 100 GPH flow may be insufficient for trucks with tuners or larger injectors. If you plan to push your LML beyond 450 HP, look at the 165 GPH version. For a stock daily driver, this pump offers excellent protection in a small package.
- 100 GPH flow suitable for stock to mildly tuned LML.
- 2-micron absolute filtration in a compact package.
- Adjustable pressure regulator for fine tuning.
Pros: Small footprint simplifies mounting in tight spaces.; Adjustable pressure adds flexibility for different fuel systems.
Cons: Not recommended for engines over 450 HP.; Some users report difficulty priming after filter changes.
6. BD Diesel 105 GPH Lift Pump: Budget Friendly Option
We researched the BD Diesel 105 GPH lift pump as a budget entry point for LML owners. It offers a modest 105 GPH flow and a simple mechanical design that is easy to install. Owner feedback indicates it works adequately for stock trucks that primarily need to prevent air intrusion. In our evaluation of value, this pump is the most affordable option, but we have significant concerns about its filtration and pressure.
The 30-micron filter is coarse and does little to protect the CP4 from the fine debris that causes failures. The 10 psi pressure is also lower than the recommended 15 psi for LML systems, which may lead to fuel starvation under high demand. We recommend this pump only as a temporary solution or for owners who plan to add a separate high-efficiency filter. For serious CP4 protection, invest in a pump with finer filtration and higher pressure.
- 105 GPH flow suitable for stock LML engines.
- Simple mechanical design with fewer electrical connections.
- Affordable price point for budget-conscious owners.
Pros: Low cost makes it accessible for basic fuel system protection.; Easy installation with minimal wiring.
Cons: 30-micron filtration provides minimal CP4 protection.; Lower 10 psi pressure may not meet some fuel system demands.
7. Parker Hannifin 120 GPH Fuel Pump: Industrial Grade Alternative
We evaluated the Parker Hannifin 120 GPH pump as an industrial-grade option for LML owners who want to build a custom fuel system. The pump itself is built to high standards and offers reliable flow, but it lacks any filtration or pressure regulation. Owner feedback is mixed, with some praising the pump’s durability and others frustrated by the need for additional components. In our assessment, this is not a plug-and-play solution.
We found that the total cost and installation effort can exceed that of a complete kit, making it a poor value for most users. The low pressure (8-12 psi) also requires careful tuning to avoid fuel system issues. We recommend this pump only for experienced DIYers who already have a filtration and regulation setup. For the vast majority of LML owners, a purpose-built lift pump kit is a better choice.
- 120 GPH flow from a reputable industrial pump manufacturer.
- No integrated filtration, requires external filter setup.
- Low pressure range (8-12 psi) may need regulator adjustment.
Pros: Durable industrial construction for extreme durability.; Can be integrated into custom fuel systems.
Cons: No included filter, increasing total cost and complexity.; Installation requires custom wiring and bracket fabrication.
Frequently Asked Questions
What does a lift pump do for an LML Duramax?
A lift pump supplies a steady flow of fuel from the tank to the high-pressure CP4 pump, preventing air intrusion and cavitation. It also helps cool and lubricate the CP4, reducing the risk of catastrophic failure. Many lift pumps include filtration to remove contaminants before they reach the injection system.
Do I need a lift pump on a stock LML?
Yes, even on a stock LML, a lift pump is recommended to protect the CP4 pump. The CP4 is known for failures due to fuel contamination and lack of lubrication. A lift pump with fine filtration (2-3 micron) can significantly extend the life of your fuel system, especially if you use biodiesel or have poor fuel quality.
What flow rate do I need for my LML?
For a stock LML, 95-100 GPH is sufficient. If you have mild tuning or towing, 120-165 GPH is recommended. Heavily modified trucks (over 600 HP) should use 165 GPH or higher. Always ensure the pump’s flow exceeds your engine’s fuel demand at full load.
Can I install a lift pump myself?
Many lift pump kits are designed for DIY installation with basic hand tools and mechanical knowledge. Most kits include brackets, wiring harnesses, and instructions. However, some require drilling or custom wiring. If you are not comfortable with fuel system work, professional installation is recommended.
How often should I change the filter on my lift pump?
Filter change intervals vary by pump and fuel quality. Most manufacturers recommend every 15,000 to 25,000 miles. If you notice a drop in fuel pressure or increased pump noise, check and replace the filter sooner. Always use the specified filter to maintain proper flow and protection.
Our Verdict
After researching and comparing the top lift pumps for the LML Duramax, our top pick is the FASS Titanium Signature Series 165 GPH for its superior filtration, strong construction, and high flow that supports both stock and modified trucks. The runner up is the AirDog II-4G 165 GPH, which offers adjustable pressure and a proven track record. For budget-conscious stock owners, the S&S Diesel 165 GPH kit provides excellent value, though with coarser filtration.
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