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

This kit contains the necessary 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 DmaxStore Left Head Gasket Part# DMAX-7785 (C-Series)
  
• 1 x DmaxStore 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 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.