Newest Book! Duramax Diesel Service Guide

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The above repair order was created May 17, 2021 by our local GM dealership. I had requested a quotation for replacing the Duramax head gaskets in my 2001 GMC. This was my first contact with them about this proposed project. You can see that their shop rate was $139.00/hour. Let that soak in a bit as you prepare for discovering just how many hours it takes to R&R the head gaskets on a Duramax 6600.

The following quote fleshes out the parts and labor costs to perform a head gasket replacement by our local GM dealership. It's breathtaking...

Now, I like and trust this particular dealership. I've known their lead diesel mechanic for more than 14 years. He is a Duramax enthusiast, who has been inside these engines enough to be very good at it. But still.... $2,232.44 in parts and $4,948.40 in labor, for a total of $7,310.84... This does not include anything other than new head gaskets, new head bolts, cylinder head decking, miscellaneous fluids and hoses/seals/sealants, and 36 hours of shop rate labor.



For my 2001 GMC, I was able to replace the head gaskets in my own shop using new gaskets, 8 new SAC injectors, 8 new injector fuel lines, new ARP head studs, cylinder head decking and a range of other smaller items for about $3500.

Replacing the head gaskets in Lil Red's Duramax 6600 using just new gaskets and new factory head bolts cost me only about $300.00 - a tiny amount compared to the dealer quote.

As of 6/2023, the GMC had accumulated approximately 11,000 miles since getting new head gaskets and injectors. Lil Red has accumulated more than 4,000 miles since replacing its head gaskets. Both continue to run and drive as well as when each of their Duramax 6600 engines were new. The head gasket replacements, injector service, injector cup service, valve train adjustment, and all the rest have been completely successful.

$7,000+ should be incentive enough for nearly every Duramax owner to do this work themselves. It's not that difficult with the right information. You can get the right information, our Duramax Service Guide (see link below), for the cost of just over a half hour of shop rate labor. Let us help you do the best job possible and for the lowest cost.

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This photo shows the point in a head gasket replacement where the heads had been removed and the block prep was about to begin.

Actually, getting to this point created a new enthusiasm to move forward with the project because I could now begin the process of re-assembly. I had already successfully completed a head gasket replacement project on my 2001 GMC just a few days prior, so this one seemed easier... I only wish I'd had the "Duramax Service Guide" before beginning.

Here's what it looked like before/after replacing the head gaskets:

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I appreciate feedback. Here's a response to receiving our Duramax Service Guide that I thought I'd share.

February 11, 2024
RE: The Diesel Page - Duramax Diesel Service Guide
Jim,

Thank you very much for putting together an awesome guide. It is funny how similar many Duramax owners' stories actually are. As an original owner of a 2003 LB7, it was the daily driver for much of ~12-15 years until small repairs crept up and the arrival of several additions to the family along the way pulled attention and priorities away from upkeep. I eventually had to tackle the water pump replacement about 7 years ago, and just had the slave cylinder on the ZF fail in the bellhousing right before Thanksgiving last year. (Thank goodness it blew right as I was starting to pull out of the driveway). Spent the better part of a 3-day weekend putting in a new clutch and flywheel, which led to the typical repair-creep with trucks this age. The more you crawl underneath, the more I found that needed attention. The plastic clutch pedal assembly actually snapped in half, U-joints were factory and were in need of replacement, fuel lines corroded at the cooler.

So fast-forward after a few months of several odds and ends to get it running right. I have had the slight smoke in exhaust for a year or two now, and verified that 2 injectors (4 and 8) are out of spec on balance rates. The idea of opening the valve covers is something that just terrifies me, so your guide is giving me the knowledge and confidence that it is something I can do. Still working towards getting to that rather large investment of an injector set, but I want to do it right and I want to go with the SAC style injectors, so making sure I can get to the complete kits with all replacement lines and hardware. As noted before, something always goes wrong during the work with a truck this age.

Again, thanks for such a great guide.
Take Care,
Chris R.