DHD 030-5001 Billet Rear Engine Cover Coolant Block Off Plate
DHD's Billet Coolant Passage Block Plate is used to stop the problematic Duramax coolant leak where the stock cast plate is installed on the rear engine cover. Use this to fix your current coolant leak or to prevent a possible future coolant leak. The plate is machined out of a block of billet aluminum and has a built in O-Ring for a 100% leak proof seal. No gasket is required for installation. Don't be fooled by cheap alternatives! This plate is the ORIGINAL and MADE in USA.
Note: This is an excellent upgrade to perform when changing, upgrading downpipes. We recommend accessing this plate via the passenger side wheel well.
Features:
Fitment:
2001-2018 Duramax 6.6L LB7 LLY LBZ LMM LML L5P

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Reviewed by: Jeff07/24/2026 12:42PM
Product ownership: Less than 1 month
Purchased from: Dirty Hooker Diesel
Comments:
Great product. If you have the tools and the patience then you can do this yourself! So glad not to be dealing with the defective part from GM! Thank you DHD for making a great product!