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Product / Pressure Washers / 85.119.025B

CAT 66DX40G1I Pump Assembly – 4.2 GPM, 4,400 PSI, 1" Shaft

CAT 66DX40G1I Pump Assembly – 4.2 GPM, 4,400 PSI, 1" Shaft

Specifications

UNLOADER

External 85.300.037

WARRANTY

5 Years

RPM

3,450

PUMP MODEL

CAT 66DX40G1I

PUMP TYPE

Triplex

Oil Type

30W Non Detergent

Oil Capacity

18 oz

Thermal Relief Value

85.300.023

Manifold Type

Brass

Soap Injector

Adjustable 85.400.000

Discharge Size

3/8" Brass QC 85.300.108

Inlet Size

3/4" GHF

Plunger Piston

Ceramic

Unloader Type

External 85.300.037

Max GPM

4.2

Shaft Size

1"

Direct Drive

Gas

Weight

27 lbs

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PRODUCT

DESCRIPTION

Pro Triplex Pump for Extreme Cleaning

The CAT 66DX40G1I Pump Assembly (Bare Pump Part #85.110.025) is a heavy duty triplex direct-drive gas pump for pros, industrial users and anyone who needs maximum performance from their equipment. 4,400 PSI at 4.2 GPM. Ideal for the toughest cleaning applications from construction sites to fleet maintenance and industrial equipment care.

Built by CAT Pumps, a global leader in innovation and reliability, the 66DX40G1I has a brass manifold, ceramic plungers and external unloader for maximum durability and serviceability. 5 year warranty. Built to last in tough conditions.

Features

  • Bare Pump Part #: 85.110.025

  • Pump Manufacturer: CAT Pumps

  • Pump Model: 66DX40G1I

  • Pump Style: Triplex, direct-drive gas

  • Max PSI: 4,400

  • Max GPM: 4.2

  • Shaft Size: 1" horizontal shaft

  • Unloader Type: External (85.300.037)

  • Plunger (Piston): Ceramic for maximum heat and wear resistance

  • Inlet Size: 3/4" GHF (garden hose fitting)

  • Discharge Size: 3/8" Brass QC (85.300.108)

  • Soap Injector: Adjustable (85.400.000)

  • Manifold Type: Brass

  • RPM: 3,450

  • Max Inlet Temp: 60°C / 140°F

  • Thermal Relief Valve: 85.300.023 included

  • Oil Capacity: 18 oz

  • Oil Type: 30W non-detergent oil

  • Weight: 27 lbs

  • Warranty: 5 Years

Built for ProsTriplex Plunger Design

The triplex plunger design is the industry standard for pro-grade pumps. Smoother operation, higher efficiency and longer life than axial pumps. Three precision ceramic plungers resist heat and abrasion for long term performance in the toughest environments.

4,400 PSI and 4.2 GPM for heavy duty cleaning: stripping paint, blasting grease and oil from machinery, washing large vehicles or construction equipment.

Rugged Construction

The CAT 66DX40G1I Pump Assembly is built with materials and components for reliability and strength:

  • Ceramic plungers for heat and abrasion resistance for long life.

  • Brass manifold for superior corrosion resistance and heat dissipation to protect seals and internal parts.

  • 1” horizontal shaft for compatibility with a wide range of gas powered engines used in pro-grade pressure washers.

27 lbs. Robust build without sacrificing installation and maintenance efficiency.

Convenient Features

Built for maximum control and ease of use for the operator:

  • External unloader (85.300.037) for precise pressure regulation and easier servicing than built-in unloaders.

  • Adjustable soap injector (85.400.000) for controlled detergent application for tough jobs.

  • Brass quick-connect discharge (3/8” – 85.300.108) for fast setup and leak free hose connection.

  • Thermal relief valve (85.300.023) to protect the pump from overheating during extended bypass cycles by releasing overheated water.

Maintenance

Easy maintenance extends the life of the pump:

  • 18 oz of 30W non-detergent oil for lubrication.

  • Oil checks and changes are simple tasks to keep the pump running at peak performance.

  • Can handle water inlet temperatures up to 140°F (60°C) for flexibility in cleaning applications.

These service friendly features make the 66DX40G1I a long term solution.Applications

The CAT 66DX40G1I Pump Assembly is a versatile pump for the toughest cleaning jobs. High PSI and strong water flow for multiple industries:

  • Construction Sites – Mud, concrete residue and debris from tools and heavy equipment.

  • Fleet and Vehicle Washing – Buses, trucks, trailers and large vehicles.

  • Agriculture – Tractors, harvesters and implements.

  • Industrial Applications – Grease, oil and grime from large machinery and work areas.

  • Property Maintenance – Siding, decks, driveways and walkways.

  • Surface Preparation – Coatings, paint or mold from surfaces.

Product Details

  • Part #: 85.110.025

  • Manufacturer: CAT Pumps

  • Model: 66DX40G1I

  • Style: Triplex, direct-drive gas

  • Max Pressure: 4,400 PSI

  • Max Flow Rate: 4.2 GPM

  • Shaft Size: 1” horizontal shaft

  • RPM: 3,450

  • Unloader: External (85.300.037)

  • Soap Injector: Adjustable (85.400.000)

  • Manifold Material: Brass

  • Plunger Material: Ceramic

  • Inlet Connection: 3/4” GHF

  • Discharge Connection: Brass QC 3/8" (85.300.108)

  • Oil Capacity: 18 oz (30W non-detergent oil)

  • Thermal Relief Valve: 85.300.023

  • Max Inlet Temp: 60°C / 140°F

  • Weight: 27 lbs

  • Warranty: 5 Years

CAT Pumps Quality

CAT Pumps are known worldwide for precision and durability. The 66DX40G1I Pump Assembly carries this forward with triplex design, brass manifold, ceramic plungers and external unloader for pro-grade cleaning.

5 year warranty. Long term peace of mind and reliability.For maximum PSI and flow and tough jobs.

Frequently Asked Questions about Pressure Washers

How to store a pressure washer?

To ensure the durability of your heavy duty pressure washer:

  • Empty the gas tank to prevent fuel from degrading or clogging the engine.
  • Empty the pump and hoses of any remaining water.
  • Perform necessary maintenance before storage.
  • Store in a dry area.
  • Cover.

What is a pressure washer?

A power washer is a cleaning machine that uses a gasoline engine to power a high pressure water pump and nozzle. It’s used to clean driveways, decks, vehicles, outdoor furniture and more by spraying water at high PSI to remove dirt, grime, mold and other debris.Many models also come with a detergent tank for added cleaning power.

How does a power washer work?

A power washer works by drawing water from a connected hose and pumping it through a high pressure nozzle. The gas engine powers the pump which pressurizes the water and then expels it through the nozzle at high speed to clean the surface. The water pressure is measured in PSI (pounds per square inch) and the flow rate is measured in GPM (gallons per minute).Many models also feature adjustable water pressure settings to cater to different cleaning needs. BE makes pressure washing easy with models available for light jobs and heavy duty commercial cleaning projects.

Gas vs Electric power washers?

The main difference is that a gas pressure washer, known for its cleaning power, is powered by a gasoline engine, making it more powerful and portable, while an electric pressure washer is powered by electricity and is generally quieter and lighter.

Gas pressure washers are for heavy duty and large areas due to their durability, whereas electric pressure washers are for smaller jobs.

Your BE electric pressure washer is perfect for smaller jobs and built for portability, and we offer a wide range of electric models. Included with our electric models is a long extension cord for use anywhere around your house.

What to consider?

When choosing a gas pressure washer consider:

  • Pressure (PSI): More PSI means more cleaning power but also more potential for damaging delicate surfaces.
  • Flow Rate (GPM): More GPM means faster cleaning as more water is dispensed.
  • Engine Power: Bigger engines mean more durability and power.
  • Portability: Weight, handle design and wheel size for easier to move.
  • Nozzles: Multiple spray nozzles to adjust the spray pattern for different tasks.
  • Adjustable Nozzle: Allows for fine-tuning the spray intensity and pattern for various cleaning needs.

How much pressure do I need for?

The required pressure (PSI) and cleaning power depend on the surface you’re cleaning:

  • Light duty (car washing, outdoor furniture): 1,300-1,800 PSI.
  • Medium duty (patios, fences, decks): 2,000-3,000 PSI.
  • Heavy duty (driveways, brick walls, large equipment): 3,000+ PSI.

Many pressure washers come with adjustable pressure settings to handle different cleaning tasks effectively.

Can a pressure washing damage surfaces?

Yes, a power washer can damage surfaces if used incorrectly. High pressure water can strip paint, dent soft surfaces or even cause structural damage if the pressure is too high or the nozzle is held too close to the surface. Always use the right PSI for the material you’re cleaning and keep a safe distance from delicate surfaces.

To prevent damage, consider using a model with adjustable pressure settings.

How to maintain your pressure washer?

To ensure the durability and smooth operation of a pressure washer:

  • Change the oil as per manufacturer’s instructions.
  • Clean or replace the air filter to ensure good airflow.
  • Inspect and clean the nozzle regularly to prevent clogs.
  • Drain the gas tank if you’re storing the washer for a long time.
  • Check the hoses for leaks or damage and replace them if needed.
  • Follow regular maintenance requirements to keep the washer in optimal condition.

Can I use a pressure washer in cold weather and low water temperature?

You can use a pressure washer in cold weather but it’s more difficult. The water flow rate in the hoses and pump can freeze and damage the equipment. If you plan to use your pressure washer in cold temperatures make sure to winterize it and store it in a warm area when not in use. You can also use anti-freeze solutions for pressure washers.

Some models are designed to use hot water, which can be particularly effective for cleaning in cold weather.

Do I need any accessories?

Common accessories for power washers: