GM/Detroit 6.2L Diesel

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6.2L Diesel

Detroit 6.2L Diesel





The 6.2L diesel was introduced for the 1982, following the retirement of Oldsmobile's 5.7L diesel. The 6.2 was manufactured by Detroit Diesel, an arm of General Motors at the time. GM never intended for Detroit's 6.2L diesel to perform the heavy lifting. They wanted an engine that could haul hay to, from, and around the ranch while consuming as little fuel as possible. Additional, the robust design of a diesel would mean the engine would outlast a comparable gasser. Properly tuned and maintained, the engine was good for fuel economy figures well into the 20's; hard to beat with a small block gas V-8 choked down by emissions equipment. Being naturally aspirated, the 6.2L diesel has a relatively high compression ratio. The heart of its injection system is the Stanadyne DB2 injection pump, the same pump used on the 5.7L Olds, International's 6.9L/7.3L IDI, and the later 6.5L diesel. 6.2L diesel engine block's and cylinder head's were produced from cast iron. Interestingly, the engine was offered in 1/2 ton, 3/4 ton, and 1 ton GMC/Chevrolet pickups.


6.2L Diesel Specs


Detroit 6.2L V-8 diesel.

Years Available:

1982 to 1993 model years.


6.2 liters, 379 cubic inches.

Compression Ratio:

21.5 : 1


3.98" (101 mm).


3.80" (97 mm).


Naturally aspirated (no turbocharger).


Indirect injection (IDI), Stanadyne DB2 rotary injection pump.


Overhead valve (OHV), 2 valves per cylinder.

Oil Capacity:

7 quarts with filter.

Engine Weight:

Between 700 & 750 lbs.

Max Engine Speed:

4,200 rpm.

Peak Horsepower:

Introduced at 130 hp @ 3,600 rpm, maximum offered during production was 143 hp @ 3,600 rpm. The United States Army's version was rated at 165 hp @ 3,600 rpm.

Peak Torque:

Introduced at 240 lb-ft A 2,000 rpm, the maximum offered rating during production was 257 lb-ft @ 2,000 rpm. The United States Army's version was rated at 330 lb-ft @ 2,100 rpm.


The 6.2L diesel was ordered with regular production option codes (RPO) LH6 (C series) and LL4 (J series). Many vehicles Employed by the United States' Army were powered by the 6.2L diesel, from pickups to HUMVEES. The Army version had a higher output rating of 165 horsepower and 330 lb-ft of torque, quite an increase over the production engines. While there are a number of high mileage examples, the 6.2L suffers from many reliability issues, including cracks forming and propagating in the engine block, flywheel, harmonic balancer, and crankshaft failures, and problems with the PMD (pump mounted driver). Overall, the engine is has not been particularly popular, but had its place in the market and a moderately sized following, even today. A popular trend is to acquire an 80's 6.2L diesel powered half ton and swap in a built gas engine. The 1980's diesel chassis does not require any emissions inspections, and fans of the 1973 to 1987 body style can modify the trucks as much as they want without running into registration issues. This is an alternative to finding a 1975 or older chassis, which limits the pool of trucks to choose from (pre 1976 trucks do not require SMOG inspections in CA and states with similar laws.