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Mack MP7, MP8, MP10 DOC : OEM 21756505

MACK MP7, MP8, MP10 DOC : OEM 21756505

Shipping ICON

ORDERS PLACED BEFORE 3PM EST WILL SHIP SAME DAY

WARRANTY ICON

WARRANTY
1M MILES OR 1 YEAR

$1,627.40

CORE CHARGE:

$500.00
iCORE DISCLAIMER: The CORE charge is a 30 day hold and will not be processed as long as the CORE is returned within 30 days. If you do not have a CORE or fail to return the CORE within 30 days, the CORE charge hold amount will be processed at that time.

AVAILABILITY IN STOCK
OEM NUMBER 21756505
PART TYPE DOC
BRAND
ENGINE MAKE Mack
ENGINE TYPE MP7, MP8, MP10
YEAR
PART NUMBER 114-0024-1

PRODUCT DESCRIPTION

This is a New, DOC, part number 114-0024-1 ( OEM Part Number 21756505 ). This part is primarily made for a Mack MP7, MP8, MP10, and comes with a One Million Miles or One Year Warranty. For additional warranty info Click Here

OEM NUMBERS

Primary OEM21756505
Additional OEM21212405, 21756505, 21756511

ADDITIONAL DETAILS

CONDITIONNew
UPC / Barcode00840490539426
WEIGHT44.00 LBS

SHIPPING OPTIONS

Ship Weight : 44.00 LBS
UPS Ground, 2nd Day Air, Next Day Air

SHIPPING POLICY

Tamerx Diesel Products ships via UPS Ground. Next day air shipping can be arranged for a reasonable price of anywhere from $50.00 - $100.00 depending on the weight of the product and your location. We will do everything we can to make sure that you get the service you need. We understand how important it is to receive your order as quickly as possible.
In most cases Tamerx Diesel Products only needs one address, as long as your product is shipping to the same location as your billing information. In order to eliminate credit card fraud, your billing information must match the credit card you provide.

The terms, conditions, and details of our warranty vary from product to product. Specific warranty details can be found below.

Tamerx Diesel Products provides a replacement warranty on all of our parts. The duration and mileage limitations of the warranty vary by product and are specified on the product's detail page/item listing.

Please note that the warranty covers replacement of the part and the cost of shipping the replacement part to you only. It does not cover any shop, labor, towing, or any similar or related costs. This is not a "money back guarantee".

If you experience a problem with your part or it is not functioning properly, the correct warranty procedure is to call us at (510) 257-1777 (8:00 AM - 5:00 PM ET Monday through Friday). Be sure to have your order number and/or other relevant order information ready so we can easily locate your order and resolve your issue as quickly as possible. From that point, we will review with you any troubleshooting steps that may need to be taken and other areas or systems that can be checked to rule out external problems contributing to your part's issue. If a replacement is determined to be necessary, we will then arrange for your replacement part to ship out ASAP and issue any necessary return shipping labels and/or documents.

As is the case for the majority of the diesel products sold on Tamerx Diesel Products, your part's warranty is active as soon as you install it. In some other cases, warranty activation is contingent upon you sending us your core (i.e., your old part). Tamerx Diesel Products will provide you a return shipping label for parts that have a warranty with a core return condition. When we have received your core return, the part's warranty coverage begins. We reserve the right to void the product warranty if your core is not received within the allotted time, or if it isn't received at all. If the warranty for the diesel part you are purchasing has a core return requirement, it will be clearly noted on the product detail page/item listing.

What is a Core Charge?

A core charge (also called "core deposit") is similar to the deposit you might pay for a can or bottle of soda and is a standard requirement in the auto parts industry. For example, in many states, to promote recycling, you pay a deposit when you purchase a can of soda and receive your deposit back when you return the empty can. Many automotive parts have a core charge, or core price, that works in essentially the same way as a soda can deposit.

30 Day Core Charge Hold

You authorize Tamerx Diesel Products, to hold your credit card for the specified core charge amount and that you agree to return your core with 30 days of receiving the purchased part. When we have received your core return, the hold is released and the core charge payment is canceled.

The customer, or parts buyer, is responsible for any shipping costs associated with core returns unless otherwise specified in the product listing/detail page. Tamerx Diesel Products offers prepaid UPS shipping labels (SKU numbers UPS-CR1 and UPS-CR2) for use in returning your core that are available for purchase on our website during your shopping/order process.

The shipping label you will need to use for the core return is dependent upon what part you are purchasing. UPS-CR1 is good for cores weighing up to 20 pounds. UPS-CR2 is appropriate for shipping cores weighing 21 pounds or more. You must include enough information with the core return that clearly identifies it as a.) a Core Return, and b.) contains enough information we can use to clearly associate the core return with your order. Including a copy of the invoice or packing slip that came with the original shipment, clearly marked "Core Return", is ideal. Alternately, you can include a note marked as "Core Return" that includes your order number, full name and address, and phone number or other contact information. Failure to include this information with your returned core will most likely delay any due core credit being issued and/or delay any applicable warranty activation. Core returns need to be for the exact part purchased and cannot be damaged. Substituting another part in place of the part you have purchased is not acceptable.

All fluids must be drained.

If you have purchased a set or a parts package, you will need to return cores for all components of the set. For example, if you have purchaed a high pressure oil pump with an IPR valve, you will need to return both HPOP and IPR valve cores to receive proper credit. If you have purchased an EGR cooler/EGR valve package, your core return must consist of an EGR cooler core and an EGR valve core, or core credit will not be given.

Core Charges are often mandated by state legislature, and, as such, the actual core charge and taxes on the charge may vary depending on the state in which you buy your part. The Tamerx Diesel Products core charge presented to you online today with your item is representative of the most common core charge.


Reliable exhaust treatment is provided by the Mack MP7, MP8, MP10 DOC: OEM 21756505, designed as a direct-fit solution for select Mack diesel engines. Manufactured to OEM specifications, this diesel oxidation catalyst helps reduce harmful emissions while maintaining consistent system operation. Its rugged build ensures durability in tough environments, supporting both engine efficiency and regulatory compliance. By choosing an OEM DOC, you avoid compatibility issues and promote long-term dependability. This component is an excellent choice for keeping Mack-powered trucks running smoothly and without interruption.

PEOPLE ALSO ASKS | BLOG(S)

If you operate a Mack truck equipped with an MP7, MP8, or MP10 engine, there's a good chance your emissions system includes the Diesel Oxidation Catalyst (DOC), OEM 21756505. This component may not be visible during daily use, but it plays a critical role in reducing harmful emissions and keeping your vehicle compliant with EPA regulations.

The DOC is the first component in your truck’s aftertreatment system. As exhaust gases leave the engine, they pass through the DOC where essential chemical reactions begin.

  • Converts carbon monoxide (CO) into carbon dioxide
  • Oxidizes unburned hydrocarbons (THC) into water vapor and carbon dioxide
  • Generates nitrogen dioxide (NO₂) to support passive regeneration of the Diesel Particulate Filter (DPF)

Why Is This Important?

By treating emissions early, the DOC:

  • Reduces pollutant output before gases reach the DPF
  • Enables passive regeneration, helping the DPF burn off soot during regular driving
  • Lowers maintenance frequency and system strain
  • Keeps your truck running cleaner and more efficiently

The OEM 21756505 DOC is designed for durability and direct-fit compatibility, making it a smart and reliable choice for heavy-duty applications.

Over time, even the most durable emissions components wear down — and the Diesel Oxidation Catalyst (DOC) is no exception. Whether you manage a fleet or drive a diesel daily, understanding the expected lifespan of a DOC is crucial for avoiding downtime and compliance issues.

Most DOCs are built to last 100,000 to 200,000 miles, though this depends heavily on how the vehicle is driven and maintained. A well-maintained DOC can exceed expectations, while poor fuel or engine issues can cause early failure.

Several key factors influence how long a DOC will remain effective:

  • Fuel cleanliness – Fewer impurities lead to less internal buildup
  • Oil control – Excess oil consumption can coat the catalyst
  • Driving habits – Long trips at consistent speeds help keep the DOC clean
  • Engine condition – Malfunctioning injectors or turbo components can reduce DOC lifespan
  • Maintenance frequency – Regular servicing helps prevent unnoticed damage

Monitoring DOC health ensures cleaner emissions and prevents downstream damage. Keeping your system in check starts with knowing how long it should last — and taking steps to protect it.

A faulty DOC can trigger fault codes, raise emissions, or reduce exhaust efficiency.

It is mounted in the exhaust system upstream of the diesel particulate filter.

It is built to Mack OEM specifications for durability and consistent emissions control.

es, it is engineered to comply with strict diesel emissions regulations.

Mack DOCs

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