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Featured Deals

Fuel Filter Conversion Kit for 2011-2025 Ford Powerstroke 6.7L

SKU: SD-FF-6.7P-11

CAT Fuel Filter Adapter for 01-16 Duramax 6.6

SKU: SD-CAT-DMAX

Sinister Diesel Charge Pipe Kit for 2003-2007 Ford Powerstroke 6.0L

SKU: SD-INTRPIPE-6.0-KIT

Sinister Diesel Bypass Oil and Coolant Filtration System for 2013-2018 Dodge Cummins 6.7L

SKU: SD-EOF-CF-6.7C-13

Cold Side Charge Pipe for 2011-2016 Ford Powerstroke 6.7L

SKU: SD-INTRPIPE-6.7P-COLD-11

Sinister Diesel Charge Pipe Kit for 2017-2026 Ford Powerstroke 6.7L

SKU: SD-CAI-7.3

Oil Filter & Coolant Filtration System for 2003-2007 Ford Powerstroke 6.0L

SKU: SD-EOF-CF-6.0

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Frequently Asked Questions

When does the Refund Season deals end?

Our main Refund Season deals promotion runs through the posted end date on this page. Any changes or extensions will be updated here.

Are discounts automatic or do I need a code?

Refund Season deals requires you to use "Refund"

Can I stack coupons with Refund Season deals pricing?

Coupon stacking is not permitted during sitewide Refund Season deals promotions unless specifically noted. One promo per order.

Are Clearance or Doorbuster items returnable?

Doorbusters and Closeout/Clearance items are final sale unless defective. Standard items follow our normal return policy.

How long will shipping take during the Refund Season deals?

Due to carrier volume, shipping times may be longer than usual. In-stock items typically ship within 1–3 business days.

* * * LIMIT OF 4,000 PURCHASE ENTRIES PER PERSON/EMAIL ADDRESS. * * * NO PURCHASE OR PAYMENT OF ANY KIND IS NECESSARY TO ENTER OR WIN. PURCHASE OR PAYMENT DOES NOT IMPROVE YOUR CHANCE OF WINNING. The Sinister Diesel Truck Sweepstakes is open to residents of the 48 contiguous US States & DC (excluding AK & HI), age of majority +. Void elsewhere & where prohibited. Ends 06/30/2026. Vehicle winner must pick up from Sacramento, CA, USA. Subject to Official Rules at bit.ly/TruckSweeps

Copyright 2026 Sinister Mfg. Company, Inc.. Not responsible for errors or omissions anywhere on this website . Sinister Diesel reserves right to modify, change or cancel any offer before, during and/or after any sale or transaction. Sinister Diesel ®. Copyright 2021.Sinister Diesel ®, Sinister ®, Sinister Blue ®, the color blue, Master Solution ®, Basic Solution ®, Complete Solution ®, American Born and Bred ®, Unleash Your Truck ®, Pitbull Series ®, Undelete Kit ®, Undelete Your Truck ®, Undelete My Truck ®, the Sinister Diesel logo, Spooled Up ® and all related names, product, designs and slogans, service marks, trade names, and trade dress, whether registered or unregistered that appear on this Website are proprietary to Sinister Diesel its affiliates, its licensors or their respective owners. All Rights Reserved.