PAI 621242 Injector Seal Kit – Detroit Diesel Series 60 12.7L 14L

The PAI 621242 is a premium aftermarket fuel injector seal and hardware kit designed for Detroit Diesel Series 60 engines in both 12.7L and 14L displacements. This comprehensive kit includes all the seals, O-rings, and hardware needed to properly install one fuel injector, ensuring a leak-free seal at the injector bore. PAI Industries manufactures this kit in the USA to meet or exceed OEM specifications, backed by their 2-year unlimited mileage warranty.

Signs You Need New Injector Seals

• Fuel leaking around injector or cylinder head area
• Strong diesel fuel odor in engine compartment
• Hard starting or extended cranking time
• Rough idle or engine misfires
• White or black smoke from exhaust
• Loss of power or poor acceleration
• Visible fuel weeping at injector bores
• Poor fuel economy due to fuel system inefficiency
• Performing injector replacement or engine overhaul

Kit Contents

Specifications

Cross References

This part replaces or is equivalent to the following part numbers:

• PAI: 621242
• Detroit Diesel: 23537111, 23535700
• Bosch: F00HN37860, F00HN37331, F00H410608
• Mahle: GS33633

Engine Applications

This injector seal kit fits Detroit Diesel Series 60 engines:

• Series 60 12.7L: 1987-2007 (DDEC I, II, III, IV, V)
• Series 60 14.0L: 2001-2011 (DDEC IV, V, VI)
• Series 50 8.5L: Select applications
• Horsepower Range: 330-605 HP

Vehicle Applications

The Detroit Diesel Series 60 engine was installed in Class 8 trucks and buses from major manufacturers:

• Freightliner: FLD, Classic, Century, Columbia, Coronado, Argosy (1987-2011)
• Kenworth: W900, T800, T600, T660, T2000 (1987-2011)
• Peterbilt: 379, 378, 377, 385, 386, 387, 389 (1987-2011)
• International: 9200, 9300, 9400, 9600, 9900 (select years)
• Volvo: VN Series, WIA, WG (select years)
• Western Star: 4900 Series (select years)
• Sterling: A-Line, L-Line (select years)
• Transit Buses: MCI, Prevost, New Flyer, Gillig, NABI (various models)
• Motor Coaches: Prevost, MCI, Van Hool (various models)

About the Detroit Diesel Series 60

The Detroit Diesel Series 60 is one of the most successful heavy-duty diesel engines ever produced. Introduced in 1987, it was revolutionary as the first fully electronically controlled diesel engine for on-highway applications. The Detroit Diesel Electronic Control (DDEC) system gave fleet operators unprecedented control over engine management and diagnostics. The Series 60 earned a reputation for reliability, fuel efficiency, and longevity, with many engines exceeding one million miles. Production ended in 2011 when the Series 60 was replaced by the DD15 engine to meet stricter emissions requirements.

Installation Notes

When replacing injector seals, it is recommended to replace all seals on all six injectors at the same time to ensure uniform sealing and prevent future leaks. Lubricate new O-rings with clean engine oil before installation. Inspect injector bores in the cylinder head for damage, carbon buildup, or scoring that could prevent proper sealing. Follow Detroit Diesel service manual torque specifications when reinstalling injector hold-down clamps. This kit services one injector; order quantity of 6 for a complete engine set.

This kit is also a component of PAI overhaul gasket kit 631316 (replaces Detroit Diesel 23536443). Verify your engine serial number and DDEC version to confirm application before ordering.

Handling Time
At All Pro Truck Parts we do our best to ship all orders same day for orders placed before 12:00pm Central Standard Time. Same day shipment is never guaranteed. For standard UPS or USPS shipping, you will typically receive your package in 1 - 5 business days. Shipping times are never guaranteed and All Pro Truck Parts is not responsible for lost or delayed shipments by the carrier. Carrier times vary by distance from shipment origin and may change without prior notice. Shipping price is calculated from package dimensions and weight. Calculated rates for orders will be available at checkout. Orders placed after 12:00pm CST on Fridays will not be fulfilled until the following business day, Monday morning barring a holiday.

Next Day Air Shipments
The cutoff time for UPS Next Day Air is 12:00PM. If you have missed the cutoff time but would still like to place an order for Next Day delivery, please send us a text message or email. We can try to accommodate and ship your order from another warehouse.

Incorrect Shipping prices
All Pro Truck Parts reserve the right to cancel any order, in the event shipping rates are calculated incorrectly at checkout. We will notify you at your provided contact information to give you the option to pay the correct amount, or allow you to cancel the order for a full refund. 

Free Shipping
Select products qualify for free shipping. Qualifying product groups can change without notice. Free shipping will be shipped via UPS Ground, USPS First Class or USPS Priority Mail.  

Domestic Shipping Services

• USPS Domestic Shipping Services
• USPS Priority Mail
• USPS First Class Package
• USPS Ground Advantage
• USPS Priority Mail Express
• UPS Shipping Services
• UPS Ground
• UPS 2nd Day Air A.M. (commercial addresses only)
• UPS 2nd Day Air
• UPS 3 Day Select
• UPS Next Day Air Saver
• UPS Next Day Air
• UPS Next Day Air Early
• UPS Standard

International Shipping Services

• USPS International Shipping
• USPS First Class Package International
• USPS Priority Mail Express International
• USPS Priority Mail International
• UPS International Shipping
• UPS Worldwide Expedited
• UPS Worldwide Express Plus
• UPS Worldwide Express
• UPS Worldwide Saver

Returns
All Pro Truck Parts offers lifetime returns for any reason on NEW, UNOPENED items in the original packaging with exceptions. (See sale items and special order items).
To be eligible for a return, your item must be unused and in the same condition that you received it. It must also be in the original packaging.

Used items (if applicable)
Items marked as USED at the time of sale will be accepted for return up to 30 days from the date of sale. 

Defective items (if applicable)
Defective items under manufacturer warranty will be eligible for return, as well as a full refund for the total amount paid by the customer. The following criteria must be met to be eligible. (a). The part is under manufacturer warranty (b). the manufacturer has determined the part defective for the purchased application. 

Refunds (if applicable)
Once your item is returned and received and inspected, we will send you an email to notify you that we have received your returned item. We will also notify you of the approval or rejection of your refund.
If approved, then your refund will be processed, and a credit will automatically be applied to your credit card or original method of payment, within 7 business days. For order placed by phone through a card terminal, you must call in to initiate the refund. 

Late or missing refunds (if applicable)
If you haven’t received a refund yet, first check your bank account again.
Then contact your credit card company, it may take some time before your refund is officially posted.
Next contact your bank. There is often some processing time before a refund is posted.
If you’ve done all of this and you still have not received your refund yet, please contact us at sales@allprotruckparts.com.

Sale items (if applicable)
Only regular priced items may be refunded, unfortunately sale items cannot be refunded. 

Special Order Items (if applicable)
Special order items may be eligible for a refund. The decision to accept a special order item for refund is left solely to the All Pro Truck Parts management team. 

Exchanges (if applicable)
We only replace items if they are defective or damaged. If you need to exchange it for the same item, send us an email at sales@allprotruckparts.com and send your item to: All Pro Truck Parts, 3948 Interstate 30 W, Caddo Mills TX 75135, United States.

Shipping
To return your product, you should mail your product to: All Pro Truck Parts, 3948 Interstate 30 W, Caddo Mills TX 75135, United States

You will be responsible for paying for your own shipping costs for returning your item. Shipping costs are non-refundable.

Depending on where you live, the time it may take for your exchanged product to reach you, may vary.

If you are shipping an item over $75, it is advised that you use a trackable shipping service or purchasing shipping insurance. We don’t guarantee that we will receive your returned item.
For returned items designated as "Free Shipping", any items shipped to the customer in which the customer did not pay shipping. All Pro Truck Parts will recover the cost of shipping to the customer's address from the refundable amount owed to the customer on the return and inspection of the item.