Don't Lose Your Heads

In-depth LB7 Duramax Cooling and Airflow Upgrades

- Jacob White

If you missed the December 2017 issue of Diesel World Magazine, you’ll need to snag a copy to get up to full speed on this build. But for a quick recap, this low mileage 2004 LB7 Duramax, as clean as it appears, needed some repair help. Due mostly to common failure points within the LB7 platform, most LB7’s will experience at some point in life, i.e. injectors and head gaskets. The engine showed signs of a minor head gasket leak with a pressurized cooling system, that would blow coolant out of the reservoir while towing. And the factory injectors were shot, diagnosed by the slight grayish/white haze coming out of the tail pipe and some abnormally high injector balance rates on a couple of cylinders. To resolve these issues, a complete head gasket kit and all new OEM spec injectors, injector lines, and injector cups were installed from Merchant Automotive. With the engine torn down that far for repairs, the CP3 fuel injection pump was also replaced with an upgraded Sportsman pump from Exergy Performance, which has some internal modifications for better fuel flow, especially at higher RPM’s.

With Part Two of this series, the engine reassembly gets completed and capped off with improvements to the airflow side of things, which will complement the new fueling modifications perfectly. A new turbocharger, water pump, better flowing manifolds and up-pipes and some high flow charge air piping to finish it all off with some style.

Water Pump Replacement Kit