GM/Detroit 6.5L Diesel

Related Topics:

Duramax LB7 Specs

Duramax LBZ Specs

Duramax LLY Specs

Duramax LMM Specs

Duramax LML Specs







Return to Duramax Diesel Specs.


6.5L Diesel

Detroit 6.5L DIesel






GM rolled out the 6.5L diesel in 1992, and it completely replaced the 6.2L diesel for the 1993 model year. Based on the 6.2L, Detroit's 6.5L diesel was targeted to a broad audience; the engine was more powerful than the 6.2L, so it could easily attract the attention of those in need of a weekend tow rig. On the other hand, it was available in 1/2 ton pickup models, and it was an acceptable, economical alternative to a gas V-8. The 6.5 diesel was offered in both naturally aspirated and turbocharged variants. The engine was retired from the GMC/Chevrolet pickup line at the end of the 2000 model year, as General Motors and Isuzu would roll out the 6.6L Duramax for 2001. Surprisingly enough, the engine is still being manufactured today by AM General for the United States Army.


6.5L Diesel Specs


Detroit 6.5L diesel.

Production Years:

1992 to current. Retired from the GMC/Chevrolet pickup line after the 2000 MY. AM General continues to manufacture the engine for the U.S. Army.


6.5 liters, 395 cubic inches.

Compression Ratio:

18.1 : 1 to 21.3 : 1 (varied with application, turbocharged vs. naturally aspirated).






Turbocharged and naturally aspirated versions produced.


Indirect injection, Stanadyne DB2 injection pump.


Common overhead valve (OHV), 2 valves per cylinder.

Oil Capacity:

7 quarts with filter.

Engine Weight:

In the ballpark of 750 lbs.

Max Engine Speed:

3,400 rpm.

Peak Horsepower:

Introduced at 180 hp @ 3,400 rpm. Offered as high as 215 hp @ 3,200 rpm.

Peak Torque:

Introduced at 360 lb-ft @ 1,700 rpm. Offered as high as 440 lb-ft @ 1,800 rpm.


Many variations of GM's 6.5L diesel were produced, including a special 120 horsepower (260 lb-ft) model specifically for delivery trucks. The most powerful version of the engine used in GMC/Chevrolet trucks was a 215 hp, 440 lb-ft, turbocharged model. For Silverado and Sierra pickups, the engine was backed by either a 4L80E 4 speed automatic transmission (with overdrive) or the popular NV4500 5 speed manual transmission. Common problems with the 6.5 diesel include crankshaft, glowplug, and PMD failure. Overheating is also an issue with the 6.5L, and it can lead to cylinder head cracking. In essence, the 6.5L Detroit diesel was a leap above the 6.2L, but it's generally accepted that the engine still fell short of Ford's Power Stroke and Dodge's Cummins. That all changed when the 6.5L was retired in favor of the Duramax; a 6.6L common rail that would level the playing field.