Ensure optimal fuel delivery and engine reliability with the ‌2521436 Fuel Pump Assembly‌, the ‌genuine OEM replacement‌ for discontinued part ‌2521363‌. This guide covers compatibility, failure symptoms, installation best practices, and why OEM assemblies outperform aftermarket alternatives in pressure accuracy, durability, and system integration for ‌Chevrolet, GMC, and Cadillac trucks/SUVs‌.

Product Overview & Compatibility‌
Part Numbers & Applications‌
2521436‌ (Direct Fit Replacement for 2521363):
Models‌:
Chevrolet Silverado 2500/3500 HD (2015–2020)‌: 6.0L V8 (L96), 6.6L V8 Duramax (L5P/LML).
GMC Sierra 2500/3500 HD (2015–2020)‌: 6.0L Vortec, 6.6L Turbo-Diesel.
Cadillac Escalade ESV (2015–2018)‌: 6.2L V8 (L86).
Function‌: Delivers 60–68 PSI fuel pressure via a brushless DC motor (compatible with diesel and flex-fuel systems).
Replaces‌: 2521363, 2521555, 2521672 (obsolete).
Key Features‌:
High-Performance Engineering‌:
Reinforced aluminum housing (resists corrosion from ethanol blends).
200-micron stainless steel pre-filter (prevents contaminants from entering the fuel line).
Integrated fuel sender unit (accuracy ±2% full scale).
Plug-and-Play Design‌:
Matches OEM module dimensions (Ø125mm x 300mm).
Pre-calibrated for factory ECU settings (no reprogramming required).
Technical Comparison: OEM vs. Aftermarket‌
Parameter‌ ‌OEM 2521436‌ ‌Aftermarket Pumps‌
Flow Rate‌ 280 LPH @ 65 PSI 200–240 LPH (risks lean codes)
Pressure Stability‌ ±1.5 PSI under load ±6–10 PSI (triggers P0087/P228D)
Motor Lifespan‌ 200,000+ miles 60,000–90,000 miles
Ethanol Resistance‌ E85 compatible (tested 150,000 cycles) E20 max (seal degradation)
Warranty‌ 4 years/unlimited mileage 1–2 years/limited mileage
Symptoms of a Failing Fuel Pump Assembly‌
Extended Cranking‌: Takes 8+ seconds to start (low fuel pressure).
Engine Hesitation‌: Power loss during acceleration or towing.
High-Pitched Whine‌: Audible noise from the fuel tank (worn motor bearings).
Check Engine Light‌: Codes P0087 (low pressure), P228D (pressure regulator fault).
Inconsistent Fuel Economy‌: MPG drops by 15–25% due to erratic fuel delivery.
Installation Guide‌
Tools Required‌:
Fuel pressure gauge, Torx T25, socket set (16mm, 18mm).
Steps‌:
Depressurize the Fuel System‌:
Remove the fuel pump relay (located in the underhood fuse box) and crank the engine for 15 seconds.
Access the Fuel Pump‌:
For HD trucks: Remove the bed access panel or lower the fuel tank using a hydraulic jack.
Unbolt the locking ring (counterclockwise) with a 16mm socket.
Replace the Assembly‌:
Disconnect electrical connectors and fuel lines (quick-disconnect fittings).
Align the new 2521436 pump’s arrow with the tank’s markings. Secure the ring to ‌40 Nm‌.
Post-Installation Test‌:
Reconnect the battery and cycle the ignition 3 times to prime the pump. Check for leaks with a pressure gauge (target: 65 PSI).
Where to Buy & Red Flags‌
Trusted Suppliers‌:
GM dealerships, ACDelco Direct, GenuineGMparts.com.
Avoid‌:
Pumps missing ACDelco/GM holographic labels or SAE J2595 certifications.
Units advertised as “universal” requiring wiring harness modifications.
Maintenance Tips‌
Replace the fuel filter every ‌50,000 miles‌ to prevent pump strain.
Maintain a minimum fuel level of ¼ tank to avoid overheating the pump.
Use Top Tier diesel or gasoline to minimize injector clogging.
FAQ‌

Q: Does 2521436 fit a 2017 Chevy Silverado 3500 with the Duramax engine?‌
A: Yes – Compatible with all 2015–2020 Silverado HD models, including diesel variants.

Q: Why does my new pump still trigger code P228D?‌
A: Likely a counterfeit part – Ensure the pump is genuine ACDelco 2521436.

Q: Can I replace the pump without removing the truck bed?‌
A: On 2500/3500 HD models, use the bed access panel near the rear axle.

Q: Are aftermarket pumps cheaper?‌
A: Yes, but OEM lasts 3x longer and prevents costly engine damage.

Q: How to test fuel pressure without a scanner?‌
A: Use a mechanical gauge on the Schrader valve (cold engine: 55–60 PSI; running: 60–68 PSI).

Conclusion‌

The ‌2521436 Fuel Pump Assembly‌ is the ‌trusted OEM solution‌ for replacing outdated part ‌2521363‌ in Chevrolet, GMC, and Cadillac heavy-duty trucks and SUVs. Engineered for robust pressure control, ethanol resistance, and extended service life, it outperforms aftermarket alternatives prone to premature failure, pressure instability, and compatibility issues. Trust genuine GM engineering to restore fuel system reliability and protect your engine during demanding workloads.

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