DON’T LOSE YOUR HEADS
pump could help with all of this, as you get better filtration, a water separator and air bubbles can be removed and returned to the tank. Another suggestion is that the LB7 injector design being placed inside the valve cover subjects it to more heat, and the internals and electronics can’t survive 100,000+ miles. An inferior metal and insufficient heat treatment on the original release injector bodies may also be partly to blame.
Again, thanks to Merchant Automotive, the LB7 Duramax platform can continue to survive and improve its lifespan with their newly released replacement injectors, which are completely new from the ground up. MA has used their years of knowledge and testing to develop their own injector that no longer requires a core return, as they don’t deal with remanufacturing injectors, which may not have the lifespan you’d expect when doing such a laborintensive job. The new MA injectors use the best materials possible, including an injector body that has been developed to eliminate cracking. Inside, the injectors receive a chrome plated ball seat for better wear and corrosion resistance. At the nozzle, the needle tip gets a Diamond Like Carbon (DLC) Coating that offers unique properties for low friction and makes them highly corrosion resistant.
Along with the replacement injectors, the MA injector package will come with everything you need to do a full and thorough injector install. New injector feed lines will be required, as the originals are prone to debris and contaminants reaching the injector when they are removed. It’s also suggested that the MA Heavy Duty return line bolts be used to replace the factory bolts, which are prone to rounding off when removed. The MA bolts will be easier to torque to spec and ensure no under valve cover fuel leaks once the job is completed.
This particular truck is a super clean, virtually, show-room condition, lowmileage 2004 model. At just 86,000 miles, the loss of coolant while towing was a sure sign of an internal engine problem and some rising injector balance rates would lead to the inevitable (breakdown?). Used mainly for towing a 40-foot, fifth-wheel travel trailer and large boat all summer long, the truck had the basic upgrades, like intake, exhaust, EFI Live Tuning, lift pump, and a built transmission, already done to it. The truck made a respectable 400hp in the tow tune and peaked at 480hp in the performance tune, so it wasn’t pushed to its absolute limits, and boost levels with the stock turbocharger were still limited to a ‘safe’ 25-psi. So, blown head gaskets were a bit of a surprise to the owner, but it just goes to show that their failure can happen in any LB7, regardless of mileage, use, and/or abuse.
In next month’s follow-up article to the head gasket and injector replacements, the engine will get some further upgrades with additional airflow from some improved exhaust manifolds and up-pipes from Dmaxstore.com, a better breathing Promax SX-E turbocharger from High Tech Turbo, and a high flow Y-bridge, piping and intake kit from Wehrli Fabrication.