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duramax logo


You need the right tools, the right technicians and the right shop to get you in and out on budget every time your diesel is down for maintenance or for a big job.  These engines are known for their power and as with all engines some have had issues but our team know what those issues are and have the experience to fix them.  Our team has been working on Duramax diesel trucks for years and has the experience you need to get the job done right the first time.  We have the right tools and we know our Duramax history!   Here is a little information on the Duramax and some history for you.


The Duramax Engine is a General Motors diesel engine family for light to medium duty trucks. The 6.6-liter Duramax Engines are produced by DMAX, a joint venture between GM and Isuzu in Moraine, Ohio. The Duramax Engine was released in late 2001 into the Chevrolet and GMC chassis vehicles. The Duramax Engine was replacing the old 6.5-L Detroit built engine which was a big jump forward in technology. GM was the first of the manufacturers to make this jump and gave GM an added advantage in the diesel truck market. The Duramax Engine utilized the new Bosch Common Rail Fuel system. The early fuel systems included an ECM (Engine Control Module), CP3 Injection pump, FICM (Fuel Injection Control Module), and injectors all of which we are familiar with and work on.

duramaxx header bb

The later version fuel system did away with the FICM and utilize a CP4 injection pump.   The Duramax Engine had some issues that appeared not too long after initial release. GM extended the warranty on the injectors to 200,000 miles due to failures that were widespread. Changing the injectors on the LB7 Duramax Engines was a little time consuming since they were located under the valve cover. Air bubbles in the fuel lines turned out to be the cause for the premature failure of the injectors. When these air bubbles were present in the fuel line they accumulated in the CP3 pump. When the injector went to fire the bubble would get between the injector plunger and the injector tip. With the bubble there, the injector plunger has no fluid damping when it comes into contact with the injector tip causing a small gap to form over time. Once that gap grows large enough fuel is allowed to flow through continuously since the  rail is pressurized so high. The computer system was unable to determine if this is happening so the check engine light would not notify the driver. The only way to determine if this was happening was to measure the return fuel flow rate. 

Here we keep up with issues like fuel flow rates and updates in the Duramax diesel engine so that we can provide quick diagnostics for you and answers quickly which equals more efficient repairs and less cost.  Trust your diesel truck to the experts!

Specialty services for Duramax include:

    Duramax injectors
    Duramax EGR coolers and valves
    Duramax CP3 injection pumps
    Oil coolers
    Head gasket replacement
    Head studs
    Turbo replacement and rebuild
    High-pressure oil pumps


Grover's Auto Repair

153 Main St
Mathews, VA 23109

location small (804) 725-7129


Weekdays:   8:00 AM - 5:00 PM
Saturdays: CLOSED