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Simpson Aluminum ALH4240 cold water gas professional pressure washer, front view

Simpson 60688 Aluminum ALH4240 4,200 PSI 4 GPM Cold Water Gas Professional Pressure Washer

$1,399.00 - $1,399.00
$1,399.00
$1,399.00 - $1,399.00
$1,399.00
In stock, ready to ship

This machine ships free by freight carrier to a commercial address with a loading dock or forklift, or to the carrier's terminal for pickup. Liftgate service brings the crate to your address and lowers it to the ground at the curb, one flat fee per order. Crated weight about 124 lb. Delivery takes 5 to 8 business days. Questions? Call (219) 327-1138.

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The Simpson Aluminum ALH4240 is one of the highest output units in the Aluminum series: a Honda GX390 commercial engine with Oil Alert drives a CAT industrial triplex plunger pump to 4,200 PSI at 4.0 GPM for concrete coatings, industrial grease and heavy equipment, and the pressure adjusts down to 1,000 PSI for lighter work. The CAT pump runs cooler than an axial pump and rebuilds at the end of its service life, and the lightweight aluminum frame moves a 4,200 PSI machine as easily as most crews handle a 3,000 PSI steel unit.

Simpson Aluminum ALH4240 4,200 PSI 4.0 GPM Cold Water Gas Professional Pressure Washer with Honda GX390 and CAT Industrial Triplex Pump on an Aluminum Frame

The Simpson Aluminum ALH4240 delivers 4,200 PSI at 4.0 GPM from a Honda GX390 engine, making it one of the highest-output units in the Aluminum series. That pressure and flow rate combination strips concrete coatings, removes industrial grease, and cleans heavy equipment faster than lower-PSI models, reducing labor hours on large commercial jobs.

Honda GX390 Engine and CAT Triplex Pump on the Simpson Aluminum ALH4240

The Honda GX390 OHV commercial series engine provides the torque needed to drive the CAT industrial triplex plunger pump at full output for extended periods. An oil alert system protects the engine during long work days. The CAT triplex pump runs cooler than axial designs and can be rebuilt when it reaches the end of its service life, giving the ALH4240 a longer usable lifespan.

Professional-Grade Aluminum Frame on the Simpson Aluminum ALH4240

Despite the higher output, the ALH4240 keeps the lightweight aluminum frame that defines the series. Adjustable pressure from 1,000 PSI to max lets operators dial back output for lighter tasks without switching machines. This lets crews move a 4,200 PSI machine as easily as most contractors handle a 3,000 PSI steel-frame unit.

Simpson Aluminum ALH4240 Features

  • Honda GX390 OHV Commercial Series Engine With Oil Alert
  • Starts easy, runs smoothly, and delivers high output; engine oil is included
  • Delivers up to 4,200 PSI to handle large jobs efficiently
  • CAT Industrial Triplex Plunger Pump
  • Triplex pumps run cooler and last longer than axial pumps; can be rebuilt
  • Develops up to 4 gallons per minute to clean quickly
  • Aircraft Grade Aluminum Platform
  • Brushed extruded aluminum tubing is strong and lightweight
  • Adjust pressure from 1,000 PSI to MAX PSI with a simple twist
  • Safety lock-out to prevent gun from being accidentally activated
  • Pro-Style Spray Wand With 5 Quick Connect Nozzle Tips
  • 0 Degrees, 15 Degrees, 25 Degrees, 40 Degrees, and soap applicator nozzles shape the spray
  • 3/8 x 50 ft High Pressure Steel-Braided Hose
  • Non-marring, kink and abrasion resistant hose lets you work in a wide area
  • On-Board Accessory Storage
  • Keeps hose, spray wand and nozzles organized
  • Siphon Tube Detergent Injection
  • Lets you use a wide variety of pressure washer-safe cleaners

Simpson Aluminum ALH4240 Specifications

Engine Brand Honda GX
Starter Recoil
HP/CC 389 cc
Fuel Tank Size 6.4 quarts
GPM 4
PSI 4,200
Pump Brand Cat
Pump Type Triplex Plunger
Adjustable Pressure Yes
Chemical Injection Siphon Tube
Frame Type Aluminum
Wheels Pneumatic
Hose Storage Hook
Hose Length 50 ft
Hose Material Rubber
Hose Diameter 3/8 Inch
Hose Connections Quick-Connect
Spray Gun Connection Quick-Connect
Spray Gun Grade Professional
Spray Gun Wand Single Wand
Spray Tips Quick Connect Tips (5)
Turbo Nozzle Sold Separately
Weight 124 Lbs.
Dimensions (in.) 40L x 24W x 26H
Engine Honda GX390
Fuel Type Gasoline
Water Type Cold Water

Simpson Aluminum ALH4240 What's In the Box

  • Simpson Professional 4,200 PSI (Gas - Cold Water) Aluminum Frame Pressure Washer with Honda Engine and CAT Pump - ALH4240

Emission Compliance Notice

This Simpson product is equipped with a Honda engine rated as 49-state compliant (EPA approved). This engine does not meet California Air Resources Board (CARB) emission standards. This model is not available for sale or shipment to California.

Simpson Aluminum ALH4240 Manuals and Documents

  • Return Eligibility: Within 30 days of delivery
  • Restocking Charges: 20% Restocking Fee
  • Refund Processing Time: Up to 9 days after approval
  • Return Shipping: Covered by the customer

Quick Overview:

  • Daily Cut-Off: Orders placed before 4:00 PM (CST) are handled the same business day. Orders submitted after this time will be queued for the next business day.
  • Preparation Time: Orders are prepared within 0 to 1 business days (Monday through Friday). During peak periods or special circumstances, this timeframe may be slightly extended.
  • Transit Estimate: Once shipped, delivery takes between 5 to 8 business days (Monday through Friday), depending on location and carrier operations.
  • Shipping Cost: Free shipping to the Continental U.S. (48 states). Machines that ship by freight carrier travel free to a commercial address with a loading dock or forklift, or to the carrier's terminal; liftgate service is a flat $95 per order, chosen above when you add the machine to the cart.
Free Shipping

Lower 48. Liftgate service available on freight machines.

30-Days Returns
SSL Encrypted Payments
Frequently Asked Questions (FAQs)

Welcome to High Pressure Car Washer! We're here to assist you in your journey to find the best pressure washer products. Please explore the sections below to find answers to common questions you might have.

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What happens after I place an order?
An order confirmation email is sent as soon as the order is placed. Orders placed before 4:00 PM CST on a business day are handled the same day, and orders placed after that time are handled the next business day. Preparation takes 0 to 1 business days, Monday through Friday. When the order leaves, a shipping confirmation email with tracking details follows.
Missing Tracking Email?
Tracking details are emailed automatically when an order ships, and orders are prepared within 0 to 1 business days, so tracking normally arrives within 3 business days of ordering. If it has not, the spam folder is the first place to check. After that, a message to support@highpressurecarwasher.com with the order number, or a note through the Contact page, lets us confirm the email address on file and check the shipment.
Shipping Time Guarantees
Delivery times are estimates rather than guarantees. Transit normally takes 5 to 8 business days after an order ships, but the destination and carrier schedules can extend that. When a delivery runs past the estimate, an additional 2 to 3 business days is the normal allowance. If the package still has not arrived after that, contacting us with the order number starts a trace with the carrier.
What is your return policy?
Returns are accepted within 30 days of the delivery date. Items must be unused, in their original condition and in their original packaging. A return starts with an email to support@highpressurecarwasher.com that includes the order number and the reason for the return; the return address and instructions are sent back from there. Return shipping is paid by the customer, and approved returns carry a 20 percent restocking fee, which is waived for items that arrived damaged, defective or incorrect. Once the returned item has been received and approved, the refund is issued to the original payment method within 9 days.
Damaged or Defective Items
Damaged and defective items are replaced or corrected. The process starts with an email to support@highpressurecarwasher.com that includes the order number and clear photos of the item and its packaging. Each case is reviewed promptly, and a replacement or correction is arranged from there. No restocking fee applies to items that arrived damaged, defective or incorrect.
Where to Find the Full Return Policy?
The complete Return and Refund Policy and the Shipping Policy are linked in the footer of every page and in the Help menu. The same return terms also appear on every product page under Return Details.
Is there a shipping fee?
Shipping is free to the 48 continental states. Accessories and portable machines ship by ground at no charge. Machines that ship by freight carrier travel free to a commercial address with a loading dock or forklift, or to the carrier's terminal for pickup. Liftgate service, which lowers the crate to the ground at your address, is a flat $95 per order, chosen when you add the machine to the cart. Orders for Alaska, Hawaii or addresses outside the 48 states are handled case by case, so customers in those areas are asked to contact us before ordering.
Can I track my order?
Every order is trackable. When an order ships, a shipping confirmation email goes out with the tracking details, and the package can be followed from that link until delivery. If no tracking email has arrived within 3 business days of ordering, a message to support@highpressurecarwasher.com with the order number lets us check the shipment.
How will my product be shipped?
The shipping method depends on the size of the item. Accessories and smaller units travel with a parcel carrier at no charge. Large machines are strapped to a pallet and shipped by LTL freight: free to a commercial address with a dock or forklift, or to the carrier's terminal for pickup, with liftgate service available for a flat $95 per order. Freight deliveries should be received in person so the shipment can be inspected on arrival, and any visible damage should be written on the delivery receipt before it is signed.
What should I consider before making a purchase?
The specifications on each product page are the starting point: PSI and GPM determine cleaning power, the power source and, for electric units, the voltage and phase determine where the machine can run, and the water temperature determines what it can clean. Matching those specifications to the intended work matters, because High Pressure Car Washer cannot be responsible for a machine used for a purpose it was not specified for. Help choosing the right unit is available before ordering by email or phone.
Additional Considerations
Two details deserve a look before ordering. The full specifications on the product page confirm the machine's capabilities, and the Emission Compliance Notice shows whether an engine-driven unit can be sold or shipped to California, since some cannot. Questions can be sent to support@highpressurecarwasher.com or asked by phone at (219) 327-1138, Monday through Friday, 9:00 am to 6:00 pm CST.
What should I expect after placing an order?
An order confirmation email arrives right after checkout. The payment method is charged at checkout, and the order enters processing, where it is prepared for shipment. Changes and cancellations are possible only before processing begins; once an order is in processing or has shipped, the return process applies after delivery.
Shipping Timeframes
Orders are prepared within 0 to 1 business days, Monday through Friday. After dispatch, delivery takes 5 to 8 business days depending on the destination and the carrier. Tracking details are emailed when the order ships.
Inspecting Your Delivery
Packaging should be inspected when a delivery arrives. If damage is visible, photographs of the packaging taken before it is opened and sent to support@highpressurecarwasher.com with the order number allow the claim to be handled quickly. For freight deliveries, any damage should also be noted on the driver's delivery receipt before it is signed.
Missing Parts or Damaged Deliveries
The contents of every delivery should be checked on arrival. If an item is damaged or a part is missing, an email to support@highpressurecarwasher.com with photos and the order number is all that is needed; a replacement or correction is arranged from there.
Tracking Information
Tracking numbers are sent by email when orders ship. If none has arrived within 3 business days of placing an order, contacting us allows the email address on file to be confirmed and the shipment to be checked.
Are you an authorized dealer for your products?
Yes, we are proud to be authorized dealers for the brands we support.
What is your privacy policy?
The Privacy Policy describes what information High Pressure Car Washer collects, how that information is used and how it is protected. It is linked in the footer of every page and in the Help menu, and questions about it can be sent to support@highpressurecarwasher.com.

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