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Cat Fuel Water Separator 423-8521(P550900)for 365C Excavator
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Cat Fuel Water Separator 423-8521(P550900)for 365C Excavator

Cat Fuel Water Separator 423-8521(P550900)for 365C Excavator

The Cat Fuel Water Separator 423‑8521 is a core protective component of the diesel‑engine fuel supply system, interchangeable with Donaldson Part No. P550900. Adopting dual‑technology of coalescing separation and depth filtration, it removes free water, emulsified water, rust, sediment, gums and microbial contaminants from diesel fuel. It feeds dry and clean fuel into high‑pressure fuel pumps and fuel injectors, protecting Caterpillar’s high‑precision common‑rail fuel system at the source.
 

Product Video

 

 

 

 

Products Description

 

 

 

Brand

Product Name

Model

Part Number

Caterpillar

Cat Fuel Water Separator 365C 423-8521(P550900)

 

 

 

Product Details

 

 

 

Product Name

Cat Fuel Water Separator

Part Number

423-8521(P550900)

Origin

US

Brand Name

CAT

Model

365C

Price

Negotiable

Packing Details

Standard Export Packing

Delivery Time

0-30 Days

Payment Term

L/C, T/T

Price Term

FOB, CIF, CFR

Supply Capacity

50,000 PCS/Month

Minimum Order Quantity

1 PC

Material

Aluminum Alloy,Stainless Steel Filter Mesh

Technology

Precision Machining

Quality

Original Factory Standard

After-Sales Service

Full Support, Online Service

Color

Standard Caterpillar Color or Customizable

Application

Excavator

Customizable

including customized materials, surface treatment and specifications

 
 

Product Features

 
 
 
365C fuel water separator
 
Technical Specifications
 

Outer Diameter: 107.3 mm (4.22 inches)

Length: 248.3 mm (9.78 inches)

Gasket Outer Diameter: 98 mm (3.86 inches)

Gasket Inner Diameter: 90 mm (3.54 inches)

Style: Spin-on Type

Filter Media Type: Cellulose

 

Product Advantages

 

 

 

 

 

High-efficiency Coalescing & Hydrophobic Filter Media

This Cat Fuel Water Separator is constructed with multi-layer composite professional hydrophobic filter material. It aggregates tiny atomized water droplets suspended in diesel into larger water beads, which then gravitationally settle into the bottom water collection chamber.

 
 

Dual Protection Performance

It integrates fuel-water separation and coarse particle impurity filtration into a single assembly. Effectively preventing fuel injector blockage and incomplete fuel combustion, it delivers dual-layer protection for stable operation of the engine fuel system.

 
 

Vibration-resistant & Leak-proof Construction

Designed with a high-tensile steel housing finished with anti-rust coating, the filter boasts outstanding wear and corrosion resistance, perfectly suited for long-term high-frequency vibration working conditions of excavators.

 
 

Complete Matching Sealing Components

The Cat Fuel Water Separator comes with an original built-in sealing gasket. It eliminates leakage hazards resulting from aging and failed old gaskets, significantly cutting down the rate of breakdowns and malfunctions.

 

 

 

 

 

Application Value

 

 

 

excavator fuel‑water separator

Reduce Maintenance Costs

 

The Cat Fuel Water Separator purifies fuel at the source, protecting high‑pressure fuel pumps, fuel injectors and other high‑cost precision components. It significantly cuts overhaul costs caused by fuel‑system failures.

Stabilize Equipment Operating Conditions

 

Ensure sufficient combustion of diesel fuel, resolve common malfunctions including insufficient power, idling vibration, difficult cold start and white exhaust smoke, and improve overall working efficiency.

Caterpillar fuel‑water separator
fuel water separator

Minimize Downtime Losses

 

This Cat Fuel Water Separator delivers stable performance, matches OEM service intervals, reduces the risk of unexpected breakdown‑related downtime, and ensures consistent construction project schedules.

 
 

Production Process

 
1

Gradient Multi-layer Filter Media Constant Temperature Setting Process

This Cat Fuel Water Separator adopts composite gradient filter material treated with high-temperature constant temperature setting technology. It precisely balances dirt holding capacity and water-oil separation performance, effectively preventing premature clogging and filtration failure of the filter element, greatly extending service life, and being applicable to scenarios with both high-quality and low-quality diesel fuel.

2

Hot-melt Integrated End Cap Sealing Process

The filter media and end caps are formed by hot-melt integrated molding technology, with no glue overflow or gaps and excellent tightness. It can withstand alternating cold and hot impact of diesel, prevent unfiltered fuel bypass circulation, and ensure 100% effective filtration.

3

Reinforced Nylon Central Support Tube

The fuel water separator is equipped with a built-in high-strength thickened nylon support skeleton with strong compression resistance. It resists continuous impact of high-pressure diesel, avoids deformation and collapse of the filter element under pressure, stabilizes the overall structure, and adapts to continuous heavy-load operation of equipment.

4

Housing Electrostatic Spraying Anti-corrosion Process

The outer shell of the Cat Fuel Water Separator undergoes electrostatic powder spraying anti-corrosion treatment with uniform paint film and strong adhesion. It effectively resists erosion from outdoor dust, humidity and rainwater, prevents rust and damage of the housing, and prolongs the overall service life of the product.

 

 

 

 

 

STONE

 
CAT  Double Grouser Shoeproduct-15-15
 
 

Stone is a leading supplier of engineering machinery parts, focusing on providing high-quality parts for mining companies. Since its establishment in 2004, we have been based in Shanghai, China, and have built our own brand STONE, becoming a trusted choice in the industry. We are committed to providing a variety of parts including bulldozers, excavators and wheel loaders for well-known brands such as Caterpillar and Komatsu. Our product line covers a full range of OEM parts, such as Track Chain, Track Rollers, Sprocket, Excavator Buckets, Blades, Excavator Cylinders, Swing Circles, and various electrical and hydraulic components to ensure that our customers' stringent requirements for quality and performance are met.

 
Top

quality

 
20+

years experience

 
Customizd

service

 
2000+

hours warrant

 

 

Q&A

 
 

 

CAT fuel water separator

Can this Cat Fuel Water Separator be interchanged with an ordinary fuel filter?

No, they cannot be used interchangeably. A standard fine fuel filter only filters solid contaminants without water separation function. Model 423-8521 is a primary fuel filter with coalescing water separation performance. They serve complementary functions and are both indispensable. They must be used together and cannot replace one another individually.

What is the replacement interval for this water separator?

Replace it in accordance with the OEM maintenance schedule under normal working conditions. If the diesel fuel quality is poor, the construction site is humid and rainy, or the machine runs under frequent heavy loads, shorten the replacement cycle accordingly. Manually drain accumulated water from the bottom regularly to extend the service life of the filter element.

What causes oil seepage or leakage after installing the Cat Fuel Water Separator?

In most cases, leakage is caused by reusing the old sealing gasket, or applying excessive/insufficient tightening torque. It is recommended to install a brand-new matching gasket every time you replace the filter, tighten it evenly with standard torque, and avoid over-tightening by force.
 

 

 

 
 
 

 

 

 

 

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