A Rough ‘N Ready GMC Duramax Project Begins

Like many gearheads, I like to keep my eye out for good deals and come across ones that I am drawn to all the time, in most cases for one reason or another (typically a lack of available funds) I have to pass on the deal and generally live to regret it. Once such a deal came across my web browser recently as I was doing my customary eBay searches for budget-priced diesel project trucks and/or cars and I just couldn’t let this one slip past.

After finding this rusty 2005 GMC Sierra 2500 HD with a running Duramax diesel engine and Allison transmission on eBay we ventured up to New Hampshire from Tennessee to pick it up (in December).

The truck in question was a 2005 GMC Sierra 2500 HD SLE base model work truck configured with an extra cab and short bed that was located in New Hampshire. The eBay listing indicated that the truck had over 217,000 miles with some rust (as expected for this generation of GM truck especially one from a northern state) and blown head gaskets but otherwise running condition with a lot of maintenance items already repaired and/or replaced on the Sierra. The truck was listed as “as is for parts or repair” but after speaking with the seller I realized that the truck was being used to drive locally, so my interest was really piqued.

I reached out to known Duramax experts and friends Mike Graves at Hollyrock Customs and Eric Merchant at Merchant Automotive for advice on whether or not the truck was worth the $1,800 asking price and if they felt it would make the 1,100-mile trip home with blown head gaskets. Both experts agreed that if everything else is working properly a Duramax engine will typically run for several thousands of miles (they’ve each heard of 20,000+) with blown head gaskets as long as the pressure is bled off and the coolant level is maintained.

When we arrived in New Hampshire the truck was as the seller described in his eBay listing and we didn’t have any surprises with the condition or our hope to be able to drive the truck 1,100+ miles home.

To help reduce pressure issues within the cooling system they both suggested removing the radiator drain petcock and removing the O-ring then reinstalling the petcock. This creates a minor leak in the system that will help prevent too much pressure from building up in the system and blowing a hose causing a catastrophic coolant leak that would overheat the Duramax engine causing more damage.

After consulting the experts I decided to pull the trigger and make the eBay purchase, while I would have preferred to have a truck and trailer available to pick up and tow the GMC Project Duramax Sierra home but that wasn’t the case so my wife and I looked for a break in the weather and mapped out our trek up to New Hampshire to retrieve the Sierra in our Chevrolet Cruze Diesel loaded with tools and supplies for the trip. Obviously a 2,200-mile round trip is too much driving to do in one sitting so we chose to break it up into three days of 12-14 hours each.

We loaded up our 2015 Chevrolet Cruze Diesel with various tools, kits, safety items, oils, and fluids and got on the road headed northbound for the marathon three-day trek from southeast Tennessee to New York on day one, then from New York to New Hampshire and back to New York on day two and finally from New York back home to Tennessee on day three with about 12-14 hours of driving planned for each day.

We left Tennessee the morning of December 9th and drove to our friends’ home about 12 hours away in New York and stayed the night. Then on Tuesday morning we drove up to the seller’s home in New Hampshire about six to seven hours to the north east and received the title and inspected the truck.

It was just as the seller stated so I climbed under the truck and removed the drain petcock from the radiator, holding my finger over the drain hole while the seller cut off the O-ring and I returned the petcock while trying to minimize the coolant loss. Next I topped off the coolant with more DexCool Prestone coolant and distilled water I purchased from our local Walmart before heading north.

Here is the reason for the purchase—the venerable Duramax diesel engine that in this case is completely stock and ready for upgrades as soon as we replace those pesky blown head gaskets that are not too uncommon in these older LLY Duramax engines. The interior isn’t plush or even very clean, but it isn’t that bad either for a 200,000-plus mile work truck. A deep cleaning will go a long way toward making it a much more inviting space. Plus, we can fix it up later if we decide to make the truck a more luxurious daily driver.

I also topped off the transmission with Royal Purple MaxATF after checking the level and realizing it was about a quart low. The engine oil looked good without any water or fuel contamination so the last thing I did was to top off the washer fluid before setting out on our trip back to New York with my wife following in our Cruze Diesel.

Before we left the seller’s home we pulled the radiator drain petcock (see arrow) and cut off the O-ring to create a very small leak in the coolant system to prevent the additional pressure from the blown head gaskets from pressurizing the system so much that we might blow a hose or tank during the drive home. We topped off the lost coolant with proper Prestone DexCool coolant and checked the other vital fluids before leaving. The transmission was about a quart low so we added a quart of Royal Purple Max ATF, then topped off the windshield washer fluid before hitting the road.

The truck ran and drove very well, but the speedometer, tachometer, oil pressure and volt meter did not work in the gauge cluster which made it a little difficult to maintain speed on the freeway. The tires were in good shape with a new pair on the rear and relatively new tires up front so the rusty old truck handled well on the road even in the rain we encountered on the way back to New York.

Windshield wipers and the heat and defroster worked great giving me good visibility even in the cold and rainy conditions. The brakes on the other hand had an issue that lead to poor brake performance causing me to leave plenty of space between cars ahead of me on the road to maximize braking distance (obviously repairing the brake system is high on our repair list).

The gauge cluster looks good, but more than half of the gauges do not work including the speedometer, tachometer, oil pressure, and voltmeter. The fuel level, transmission temperature, and coolant temperature gauges do work, but it was certainly distressing to fire up the engine and see the oil pressure gauge sitting at 0 psi!

On another positive note, the Kenwood A/V-receiver worked (rear speakers only) and its Bluetooth interface worked with my cell phone to play music, announce navigation directions and allow me to speak to my wife in the Cruze. The long drive would have been nearly unbearable without some good tunes!

When we woke up early Wednesday morning to head back to Tennessee we found that the snowstorm that we hoped to beat out of town arrived early leaving about two inches of snow on the ground. Fortunately the New York road crews take good care of the roads and had them plowed and ready to drive before we were loaded up and ready to leave.

The weather window that we thought we had for the trip closed earlier than expected with rain turning to snow through the night of day two leaving us to cope with a few inches on the ground as we left New York. The snow was with us for the bulk of the first half of the drive home from New York, fortunately, the roads were plowed and both the Cruze and Sierra managed the cold, slick, snowy and wet road surfaces without any incidents.

Again, with extra stopping distances factored in the truck handled the slick roads without issue. One other issue that we hope to address soon is that the base model Sierra SLE was not equipped with cruise control making it even more difficult to maintain consistent speed on the open interstate highways throughout our 1,100-mile trek back home.

Our general diesel truck knowledge combined with additional research and planning netted a great diesel find that we were actually able to drive over one thousand miles home. We had tools, fluids and a backup plan in place to get the truck home in the event that the trip turned bad, fortunately we had a relatively trouble free and uneventful trip home, save for having to dodge around that moron in NY that stopped in the lane when he missed his exit.

After a few hours of driving my wife noticed something flapping from the driver side front fender well at freeway speeds. During our lunch pit stop, I was able to secure the fender liner with several properly placed zip ties.

But the experiment could have just as easily gone the other way and became a disaster, leaving us stranded on the side of the freeway with a truck that wasn’t worth its weight in scrap. If you are in the hunt for a diesel pickup but just can’t afford the price of a new truck or even a late model used truck, know that there are still good deals to be had out there, do your homework and be patient and willing to work for it and you might be able to put a new (to you) diesel pickup in your driveway before you know it.

Believe it or not; all of these tools, supplies and equipment were stuffed in to the trunk of our Diesel Cruze to make sure that we would have whatever we needed for virtually any roadside problems we might encounter along the drive home from New Hampshire. It is much better to over pack and not need something than under pack and realize that the tool or part you need is sitting in the garage or tool box at home while you are stranded on the side of the freeway! Despite having all of those supplies with us for the trip; these were the only items we needed to get the Sierra home to Tennessee. The coolant and distilled water was mixed and used to top off the cooling system after removing the O-ring from the radiator petcock, the windshield washer fluid was topped off to maintain visibility in the unexpectedly snowy road conditions, Power Service Diesel Kleen was added each time we filled up with fuel since the truck had sat unused for a long period of time, one quart of Royal Purple Max ATF was used to top off the Allison transmission while the zip ties and knife were used to secure the fender liner and the lights and ARB tire pressure gauge were used to verify tire pressure before we got on the road and to light the way when checking over the truck.

The Good:

  • Drove all the way home (1,121 miles)
  • Starts, idles, and runs fine
  • Fuel level, coolant temperature, and transmission temperature gauges work
  • Transmission operates properly without any noticeable slip
  • Good tires that held up
  • HVAC/Defroster works
  • Windshield wipers and washer works
  • Bluetooth radio worked for phone calls and music
  • Averaged around 20 MPG

The Bad:

  • Brake system issues
  • Coolant system building pressure suspected
  • Blown head gaskets confirmed
  • Speedometer, tachometer, oil pressure and voltmeter gauges do not work
  • A lot of body/exterior rust
  • No cruise control
  • Passenger side rear turn signal works intermittently
  • Some cab lights are out
  • Front speakers did not work
  • Dome light does not work


  • MORE power/better efficiency and fuel mileage
  • Cruise control
  • Great brakes
  • Nicer interior (carpeting, seat covers, etc.)
  • Better sound system
  • Rust repair
  • Nice wheels and tires
  • Leveling kit, new shocks
  • Tool storage/work truck functionality
  • Bumpers (and winch?)
  • 6-speed Allison conversion


  • Head gasket replacement
  • Brake system repairs
  • Gauge cluster repair
  • Rebuild suspension; make stronger
  • Fix/upgrades lights
  • Build transmission to handle more power
  • Rust repair?

All in all, I feel that this Sierra is a great starting point for a project truck and look forward to turning some wrenches on the truck and bringing it back to its former glory and beyond. There are several possibilities for the truck and we are currently not exactly sure which way we’ll go with the project but here are a few of the possibilities that we are thinking about currently.

All of the priorities start with fixing the blown head gaskets and other major mechanical issues:

  1. Improve the performance of the engine/transmission and use it as a basic transportation/work truck.
  2. Build the truck into a rugged first response truck that we can use as a family when doing volunteer disaster relief work.
  3. Swap the drivetrain into our 2000 Chevrolet Tahoe Limited making the SUV much more powerful, four-wheel drive and more efficient than ever.
  4. Go nuts and make it a competition truck.
  5. Something else entirely.

I’m currently leaning toward options 2 and 3 but as we get into the project things could change so stay tuned. Use the comments section below to let us know what you think should be done with the truck, and follow our progress here as we whip the Northern Sierra into shape.

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About the author

Chris Tobin

Chris Tobin has been interested in motorsports since before he could legally drive. He has built, driven and raced just about everything from scale RCs to motorcycles, cars, and trucks on the drag strip and off-road.
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