Every diesel owner has a loyalty to their brand, but no engine is immune to issues—especially here in Arizona. At Impact Diesel AZ, we service them all. Over the years, we’ve noticed specific trends for each of the “Big Three” diesel engines.

Knowing what to look for can save you thousands in catastrophic repairs.

Ford Powerstroke (6.0L & 6.7L)

• The 6.0L Issue: It’s infamous for oil cooler failures and EGR (Exhaust Gas Recirculation) issues. In the Phoenix heat, a clogged oil cooler can lead to blown head gaskets fast.

• The 6.7L Issue: Generally a beast, but we see fuel system issues related to the CP4 injection pump. If this fails, it can send metal shavings through your entire fuel system.

Dodge/Ram Cummins (5.9L & 6.7L)

• The Issue: Transmissions and Injectors. The Cummins engine itself is bulletproof, but the transmissions often struggle to keep up with the torque, especially if you tow heavy loads. We also see actuator failures on the Variable Geometry Turbos (VGT) due to soot buildup.

Chevy/GMC Duramax (LB7, LLY, LBZ, L5P)

• The Issue: Water pump failures and glowing plug issues. The L5P is fantastic, but earlier models like the LB7 are notorious for injector failures that require significant labor to replace.

The Solution: Expert Diagnostics Don’t trust your specialized engine to a general mechanic. You need a shop that understands the specific weak points of your platform. We use factory-level diagnostic tools to pinpoint the exact problem—whether it’s a bad sensor or a failing turbo.

Got a Check Engine Light? Stop guessing. Bring your truck to the experts at Impact Diesel AZ near Cave Creek & Deer Valley for a diagnosis you can trust.