PAI 131656 Oil Pan Gasket – Cummins ISX ISX15 X15

The PAI 131656 is a premium aftermarket oil pan gasket designed for Cummins ISX, ISX15, and X15 heavy-duty diesel engines. This rubber-coated, steel-reinforced gasket provides a reliable seal between the oil pan and engine block to prevent oil leaks. Manufactured to meet or exceed OEM specifications, it's a direct replacement for Cummins part numbers 4026684 and 3679943. Backed by PAI Industries' 2-Year Unlimited Mileage Warranty.

Signs You Need a New Oil Pan Gasket

• Oil leaking from the bottom of the engine near the oil pan flange
• Oil spots or puddles under the truck after parking
• Low oil level warnings requiring frequent top-offs
• Visible oil residue or wet spots around the oil pan perimeter
• Oil dripping onto exhaust components causing smoke or burning smell
• Failed DOT inspection due to excessive oil leaks

Specifications

Cross References

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

• Cummins: 4026684, 3679943
• PAI: 131656, 131656E

Note: This gasket is also a component of PAI 131838 Oil Pan Gasket Kit and PAI 132114 Lower Gasket Kit.

Engine Applications

This oil pan gasket fits all Cummins ISX series 15-liter engines:

• Cummins ISX CM570 (Dual Cam, EGR)
• Cummins ISX CM870 (Dual Cam, EGR)
• Cummins ISX CM871 (Dual Cam, DPF)
• Cummins ISX15 CM2250 (Single Cam, SCR)
• Cummins ISX15 CM2350 (Single Cam, SCR)
• Cummins X15 CM2350 (EPA 2017+)
• Cummins X15 CM2450 (EPA 2021+)
• Cummins QSX15 (Industrial/Off-Highway)

Vehicle Applications

This gasket fits Class 8 trucks equipped with Cummins ISX/ISX15/X15 engines:

• Freightliner: Cascadia, Coronado, 122SD, 114SD (2001+)
• Kenworth: W900, W990, T880, T680, T800, C500 (2001+)
• Peterbilt: 389, 579, 567, 386, 387, 388, 367, 365 (2001+)
• International: LT Series, HX Series, LoneStar, ProStar, 9900i (2001+)
• Volvo: VNL Series, VNX Series (with Cummins power)
• Western Star: 4900 Series, 5700XE (2001+)
• Mack: Pinnacle, Anthem (with Cummins ISX option)

Installation Notes

Proper oil pan gasket installation is critical for a leak-free seal. Before installation, thoroughly clean the oil pan rail and engine block mating surfaces to remove all old gasket material, oil, and debris. Inspect the oil pan flange for warping or damage—a warped pan will not seal properly even with a new gasket. Apply a thin bead of RTV sealant at the corners where the front cover and rear seal housing meet the block (per Cummins service recommendations). Install the gasket dry—do not apply sealant to the gasket surface. Torque oil pan bolts in the proper sequence to Cummins specifications (typically 18-22 lb-ft for steel pans). Allow RTV to cure before adding oil and starting the engine. After installation, check for leaks at operating temperature.

Verify your engine serial number and ECM code (CM570, CM870, CM871, CM2250, CM2350, etc.) before ordering to confirm fitment.

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.