Duramax Head Gasket Replacement

[More Power]

Turns out, a proper LB7 injector cup removal/re-installation really isn't all that complicated. Shown above is the machined deck surface of an LB7 cylinder head illustrating the appearance of a properly installed injector cup(s). If you run your finger over the end of the cup, you'd just barely feel the end of the cup protruding above the deck surface. Only .004" was removed from the deck when this head was re-surfaced. While hard to see in this image, there was a barely visible ring of red Loc-Tite 272 around the end of the cup, indicating that the proper amount of sealant was uniformly applied and distributed as the cup was driven into the head. The Loc-Tite not only seals the cup once cured but also lubricates the end of the cup as it's inserted into the head. Can't install them without this sealant - they won't go in without the lubrication qualities of the sealant.



From the top side, you can see the correct position of the cups after being inserted into the heads. The video link in a previous post will show you how to properly insert each cup. For the sake of more info, the 2 large O-rings that seal the top (big end) of the cups in the head are lubricated before being inserted. I've heard of many different recommendations for a lubricant... ranging from liquid dish soap to coolant to engine oil to chassis grease. Now, these O-rings seal engine lubricant from reaching the engine coolant (or vice-versa), so from a practical standpoint, there are multiple correct answers as to which might be best. I chose to use a light coating of clean chassis grease, applied to both the O-rings and the inside of the top-side hole in the heads. The small-end of each hole should remain spotlessly clean and dry before receiving the Loc-Tite 272 sealant. It's been 4-1/2 years and nearly 20,000 miles since these photos were taken, without a hint of a coolant or oil leak. The above video link will show more detail.

Jim

PS... The printed Duramax Diesel Service Guide linked below in my signature will soon go away. There are currently just 3 of the beautifully printed versions remaining. Once they're gone... they're gone, and won't be printed again. My goal is to make every chapter of that Guide available in video format. You can help make that happen by supporting our YouTube channel and this video series with Likes, by Subscribing and posting comments to our YouTube posted videos.


Did this forum thread or YouTube video help you with servicing your Duramax? Would you like to share this information with others or help us get the word out about Duramax Head Gasket/Injector Replacement? It's easy! Simply link to us in your own YouTube video, or post the link(s) shown here in a forum post, email message or social media site. Thank you!

www.thedieselpageforums.com/tdpforum/showthread.php?46717
YouTube Channel - http://www.youtube.com/@thedieselpage

[Yukon6.2]

Thanks for the heads up on the amount of manuals left. Update there are only 2 left now.
As my towtruck is on my have to repair list for hard rad hoses...
The manual is on it's way, not that the manual will move the tow truck up the list of priorities any faster.
Thank you Jim for all you have done.

[More Power]

Thanks for the heads up on the amount of manuals left. Update there are only 2 left now.
As my towtruck is on my have to repair list for hard rad hoses...
The manual is on it's way, not that the manual will move the tow truck up the list of priorities any faster.
Thank you Jim for all you have done.

Thank you Thomas!

[Yukon6.2]

Got the book safe and sound
I haven't been getting much shipped from the states lately and it showed. Had a brain fart and should have had it sent to my Alaska address. Probaly would have saved $50.00 by doing it that way. But seeing the tow truck is a company truck i will be claiming the costs as a business deduction
I usually discuss shipping ect to try and cut costs.So it turned out expensive, but in the end it will be worth it as it is an awesome book full of the information required to take on the job by yourself.
Customs is taking the tariff stuff seriously...had an additional $29.00 to pay to get the book out of jail.