Fits: 2004.5 thru 2005 Chevy Silverado/GMC Sierra 2500HD/3500HD LLY Duramax Diesel

This kit contains the necessary Genuine OE Replacement parts you will need to replace both head gaskets on your LLY Duramax.

Includes:

• 1 x Genuine GM Head Gasket Install Kit Part# 98403365
• 1 x Genuine OE Replacement Left Head Gasket Part# DMAX-7785 (C-Series)
  
• 1 x Genuine OE Replacement Right Head Gasket Part# DMAX-7788 (C-Series) 
• DmaxStore Exclusive: 8 x Genuine Bosch injector o-rings and copper washers
• DmaxStore Exclusive: Bosch injector o-ring part# FOOE200099
• DmaxStore Exclusive: Bosch copper washer part# FOORJ01086
  

​Optional:

• DmaxStore High Flow Thermostats
• Genuine GM Thermostats
• Mishimoto Thermostats
• MAHLE Head Bolts​
• DmaxStore Performance Head Stud Kit
  
  • ​Recommended over the MAHLE Head Bolts, these are a superior replacement for the head bolts and are rated at 220,000 psi tensile strength.

Tech tip: Installing head gaskets on your Duramax is very technical and labor intensive. You should have strong mechanical skills to complete this job, 30-35 hours should be allocated. It is highly recommended to add a DmaxStore head stud kit. Other repairs such as water pump and injectors should be considered since you will have easy access at this time. We use and recommend Genuine OE Manufacturer C series gasket because it is the thickest of the 3 available. Valve adjustments are not always necessary but should be checked.

DmaxStore Notes: This is also a good time to replace your glow plugs. The glow plugs may need replacement due to coolant contamination. If your glow plugs haven't been replaced recently, there is a slim chance they may break off in the cylinder head during removal. It is much easier to extract a broken glow plug with the cylinder heads off.