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6.2L GM/Detroit Diesel

6.2L Diesel Specs & History






General Motors introduced the 6.2L Diesel for the 1982 model year. GM felt the need to add a fuel efficient alternative to their gas guzzling V-8's. The resulting engine, manufactured by Detroit Diesel (a division of General Motors at the time), was not intended to be the workhorse of their engine lineup, but rather an economical alternative. If torque or towing was a primary concern, GMC/Chevrolet pickups could be ordered with a burly big block. The naturally aspirated 6.2L lived up to its expectations as a fuel sipper. Farmers could haul hay and tools around the ranch without tearing deep into their pockets, and make it to the feed store on a budget. While the 6.2 diesel was no heavy hauler, it certainly appealed to a particular niche market. In the long run, the 6.2 would prove to have some reliability concerns including reoccuring overheating issues, cracked engine blocks, and failures of the harmonic balancer, crankshaft, and flywheel (the three of which are often related to one another). The 6.2L shares the same bellhousing bolt patterns and motor mounts as all GM V-8 gas engines, simplifying production and integration of the diesel power plant into C/K series pickups.


6.2L Diesel Specs


Detroit Diesel (a division of GM at the time).

Production Years:

1982 - 1993


GM/Chevrolet C/K trucks, Hummer H1



Block/Head Material:

Cast iron engine block, cast iron cylinde heads.


379 cubic inches, 6.2 liters.




3.98 inches


3.80 inches


• IDI (indirect injection).
• Mechanical injectors, Stanadyne DB-2 rotary injection pump.


Naturally aspirated, no turbocharger.

Max Engine Speed:

3,600 rpm


• 130 HP @ 3,600 rpm (introductory).
• 143 HP @ 3,600 rpm (peak).


• 240 lb-ft. @ 2,000 rpm (introductory).
• 257 lb-ft. @ 2,000 rpm (peak).


The 6.2L became available following the retirement of the infamous 5.7L Olds diesel. It was available in 1/2 ton as well as 3/4 and 1 ton model pickups, which is unique to GMC/Chevrolet pickups because Ford and Dodge never offered diesels in their 1/2 ton pickups when they got into the diesel marketplace. At an option less than $1,500 and capable of surpassing some of GM's V-6 gas engines in fuel economy, the 6.2 diesel was an attractive offer. The engine's were Federally rated at up to 20 mpg city and 23 mpg highway. GM secured a government contract and provided 6.2L diesel engines and trucks to the United States Army in mass quantities, most of which can be had for a steal at government auctions. Despite some of the problems that plagued the 6.2L diesel in the long run, the engine ultimately achieved what GM/Detroit had set forth to do.