Return / Core Return Policy

To start a product or core return, view our policy below then please fill out this form.

An RMA (Return Merchandise Authorization) number is required, and must be written on the outside shipping carton.

  • Returns must be packaged securely in an outer carton
  • Do not write on the product packaging itself. Write only on the outer shipping carton.
  • Packages received without a Return Authorization Number written clearly on the outer carton will be refused.
  • Returnable items must be received by ZZ Diesel within 30 days of the product being received by you the customer. (determined by Tracking info)
  • Returned product must be in new, re-saleable condition, with all original boxes, packaging, parts, cables, manuals, etc.
  • Upon receipt, all returns will be inspected, and, at our discretion, credit may be refused or a restocking fee of 5%-10% may be assessed.
  • Original shipping charges will not be refunded.
  • Customer is responsible for shipping costs incurred to return products.

Some Circumstances in which credit will not be issued but not limited to:

  • Product has been installed and/or used
  • Product has been damaged from an attempt to be installed and/or used
  • Product is shipped back without original box, manual and/or parts
  • Seal on electrical parts is broken
  • Product serial number does not match that of which was original shipped to buyer
  • Product is deemed not re-saleable by ZZ Diesel due to customers own actions in dealing with the product
  • Custom tuned devices are nonreturnable I.E. EZ Lynk, SCT, EFI Live, etc.
  • Exhaust systems sometimes shift during transit and can be damaged on the ends. Unfortunately this is out of our control but it is an easy fix. It can be bent back into place with a crescent wrench. If unsure how to do this please contact us. If the damage is to severe we will make sure to get you a proper replacement. 


The following requirements must be met!

  • All cores must be the same model as the original item that was purchased.
  • It is the customers responsibility to properly package their core to ensure it arrives safely.
  • Customers have 30 days from the date their original purchase shipped out to return their core for a refund. Cores returned after 30 days will not be accepted. It is the customers responsibility to notify ZZ Diesel if they need a core time limit extension.
  • Core must be fully assembled and intact and all parts must be attached with all hardware.
  • All cores must be accompanied by the sales order, sales receipt or a copy of the online order. Failure to return one of these can greatly delay or prevent processing.
  • Please allow 3-5 days for cores to be processed and refunds to be issued.


  • Injectors that were involved in a fire will NOT qualify
  • When Returning Core Injectors and pumps, (you purchased and received the parts and now need to return your cores) they must be returned in original white shipping box. No box, no credit, no exceptions.
  • Core Injectors and Pumps Especially (they hold more fuel), Must be drained. If UPS/FedEx/USPS sees fluid coming out of the box, your shipment won't even make it to us, they turn it around and you get to start over!


  • Camshaft lobes must still maintain factory specs
  • Cam gear surface area must be to stock specs
  • Cam must not be rusty or pitted


  • Transfer case must be fully assembled with all parts intact. Missing parts or un assembled units may not be eligible for core credit.
  • Transfer cases must NOT have any holes or cracks in the front housing that bolts to the transmission.
  • Transfer cases must be fully drained of fluid prior to shipping.


  • Once Core Heads are returned they will be pressure checked and resurfaced. If a head fails a pressure check, or has to be resurfaced beyond specifications it will not be credited as a core.


  • Must be in rebuildable condition
  • Must be fully assembled and all hardware present
  • Must be fully drained of all fluids
  • Partial credit may be issued if damage is found in the core but it is still usable

All Edge Products, and PPE product returns will not be accepted without an RMA# from the manufacturer. Once you have received the manufacturer's RMA number you still MUST get an RMA number from ZZ Diesel. Once the product is returned and inspected you will be issued a Store Credit or Exchange.