The Best-Ever 6.5 Chevy Diesel Rebuild

Volume 1 Issue 4 - Diesel Articles

A while back, Ted Rich, of Granite Falls, Washington contacted me about a rather unique 6.5 Chevy diesel engine build for his 1998 Chevrolet 3500 4x4 dually truck. Ted, like many of you, is a GM diesel enthusiast who loves his truck. He had spent a lot of effort and money over the years getting it built up exactly like he wanted. Unfortunately, after about 150,000 miles of happy service, his engine failed. Instead of buying a new Duramax replacement, Ted challenged me to build the most durable, smoothest running and efficient 6.5L Chevy diesel engine that I could imagine. A few extra horsepower wouldn’t hurt, he said, but sheer power definitely was not his aim. Diesel Depot – with our 10 years of experience building these engines for a wide range of applications from mild to wild – accepted Ted’s challenge and began this unique engine build. My thanks to Ted, he allowed me to use my imagination and to utilize some relatively new and exciting technologies to achieve our goals.

Duramax LLY Overheating and Thermal Feedback Primer

Volume 1 Issue 4 - Diesel Articles

I love what I do, and that is a blessing. Focusing on the troublesome mysteries of the technical world, I get to figure things out: things that have no apparent explanation... the elusive.

What follows is one such mystery, wrapped in a clever disguise and hiding in plain sight for years. It remained undetected for so long because there is not a single vehicle sensor, diagnostic, or gauge that is set up to alert us to what I finally found with patience, a casual observation, a $15 gauge and a paradigm shift.

As you read, keep in mind that the principles in this article can be applied to all turbocharged vehicles, not just the Duramax. You may well find inspiration to look at other unsolved mysteries by the time we are done. If you do, I would love to hear about it.

Duramax LLY Disappointment

It was 2004 when the Duramax LLY model replaced the LB7. Promises of more power, an advanced variable geometry turbo (VGT), among other announcements, were considered worth the wait. Unfortunately, it became clear right away that there was a problem. The engine did not seem to live up to the promises. Economy was reduced, performance was hindered and many towing customers could not use it for the advertised load capacity. The vehicles even overheated. Compared to the first generation LB7 Duramax, the LLY seemed to be dragging an anchor behind it.


GM Duramax DTC Diagnostic Trouble Codes Table

Volume 1 Issue 4 - Diesel Articles

Use the "Duramax DTC Lookup" form immediately below to look up a specific diagnostic trouble code (DTC); or, scroll down the table for the same information.


Steve Johns 6.2L Diesel Hummer H1

Volume 1 Issue 4 - Diesel Articles

Steve Johns 6.2L Diesel Hummer H1

Steve Johns loves his 1993 AM General HMC4 (4-door hardtop), powered by the stock 6.2L naturally-aspirated diesel. After years admiring the AM General H1, five years ago Steve purchased this clean specimen from his local GMC dealer for $25,000.00. It had only 50,000-miles on the odometer.

Ninety-three was only the second model year for the civilian Hummers – basically modified military trucks. (You can see the tan military paint showing through on Steve’s Hummer where the factory white paint has peeled away.) This H1 includes a 12,000-pound. Warn winch, undercarriage protection, air-conditioning, rocker-panel protection, a brush guard, tow hitch, and the Central Tire Inflation System (CTIS). This truck has every factory option offered in 1993 except power windows and door locks.



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