Description
1R-0750 Secondary Fuel Filter 3-Pack for 2001–2016 Duramax 6.6L & Caterpillar Engines
The 1R-0750 secondary fuel filter is the last line of defense before fuel enters your Duramax's CP3 high-pressure injection pump — and it's the most overlooked maintenance item on these trucks. This 3-pack of secondary fuel filters provides three complete changes for 2001–2016 Duramax 6.6L engines (all generations: LB7 through LML) plus Caterpillar D4E and D6H heavy equipment. Each filter is individually sealed and manufactured in IATF 16949 certified facilities.
💡 Pro Tip: The secondary filter (on the engine, passenger side) should be replaced
every other oil change — not just when you remember. With this 3-pack, you're covered for ~45,000 miles of driving. Pair with our
billet aluminum filter head to permanently upgrade the failure-prone plastic cap while you're in there.
Key Features
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IATF 16949 Certified Filtration — Manufactured to the same quality standard required for OE suppliers to GM and Caterpillar. Consistent micron rating, flow rate, and burst strength across every filter.
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Secondary (Final) Filtration Stage — This is the engine-mounted secondary filter, downstream from the primary fuel filter/water separator. It provides the final filtration before fuel hits the CP3 high-pressure pump — the most critical filtration stage in the Duramax fuel system.
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Multi-Layer Synthetic Media — Designed for the 26,000+ psi fuel pressures generated by the CP3 common-rail system. Captures contaminants as small as 4 microns absolute to protect injector nozzles from erosion.
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3-Pack Value — Three filters at a bulk price. Covers three secondary filter changes (roughly 45,000 miles of driving for the average Duramax owner). Keep one on the shelf and never run an overdue filter.
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Dual Application — On-Highway + Off-Highway — Same filter element used in both the Duramax 6.6L and Caterpillar D4E/D6H heavy equipment engines. If you run a Duramax truck and Cat equipment, one filter SKU covers both.
Compatibility
| Application |
Year |
Make / Model |
Engine |
| Chevrolet / GMC |
2001–2016 |
Silverado 2500HD/3500HD, Sierra 2500HD/3500HD |
6.6L Duramax LB7, LLY, LBZ, LMM, LML |
| Caterpillar |
— |
D4E, D6H LGP |
Cat 3114, 3116 Diesel |
Cross-Reference
| Brand |
Part Number |
| CAT (OEM) |
1R-0750 |
| Baldwin |
BF7633 |
| Fleetguard |
P551313 |
| Donaldson |
P551313 |
| WIX |
33114 |
Installation Guide — Duramax Secondary Filter
The secondary fuel filter is located on the passenger side of the engine, mounted to the intake manifold area. It's the smaller of the two fuel filters on the Duramax — not the large spin-on filter under the driver's door (that's the primary). Tools needed: 36mm socket or filter wrench, clean rags, diesel-rated container for spills. Process: (1) Place a container under the filter housing to catch fuel. (2) Unscrew the cap/filter assembly — the filter element stays inside the cap. (3) Remove old filter, wipe the housing interior clean. (4) Install new filter into cap with new O-ring. (5) Reinstall cap — hand-tighten, then 1/4 turn with wrench. (6) Cycle key to ON (not start) 3-5 times to prime. (7) Start engine and check for leaks.
Frequently Asked Questions
Q: Which filter is this — primary or secondary?
A: This is the secondary (final) filter — the smaller filter mounted on the engine, passenger side. It's the last filtration stage before the CP3 high-pressure fuel pump. The primary filter (larger, frame-mounted under driver's door) is a separate part.
Q: How often should I change the secondary fuel filter?
A: Every other oil change, or approximately every 15,000 miles under normal driving conditions. If you tow heavy or run biodiesel blends, change every 10,000 miles. The CP3 pump relies on clean fuel — a clogged secondary filter starves the pump and damages injectors.
Q: Does this fit my Caterpillar D6H dozer?
A: Yes. The 1R-0750 is the standard secondary fuel filter for Cat D4E and D6H LGP models with the 3114/3116 diesel engine. It's the same filter element used in the Duramax — one part number for both applications.
Q: Do I need special tools for the Duramax filter change?
A: A 36mm socket or a dedicated filter cap wrench makes the job easier. The filter housing is plastic (OEM) — avoid using a strap wrench directly on the cap, as it can crack. If you're upgrading to an aluminum cap, use our billet aluminum refit head for a permanent upgrade.
Q: What happens if I don't change the secondary filter on time?
A: A clogged secondary filter restricts fuel flow to the CP3 pump. Symptoms progress from hard starting → rough idle → power loss under load → CP3 pump cavitation damage → injector failure. On a Duramax, CP3 replacement is $1,500+. A $17 filter is cheap insurance.
