| Manufacturer | Detroit Diesel, AM General |
|---|---|
| Production | 1982-1993 and 1992-current |
| Predecessor | LF9 350 cu in (5.7 L) diesel |
| Successor | Duramax V8 engine |
| Displacement | 6.2L/379cid and 6.5L/395cid |
| Cylinder bore | 6.2L: 3.98 in (101 mm); 6.5L: 4.06 in (103 mm) |
| Piston stroke | 6.2L: 3.80 in (97 mm); 6.5L: 3.82 in (97 mm) |
| Cylinder block alloy | Iron |
| Cylinder head alloy | Iron |
| Valvetrain | 16 OHV |
| Compression ratio | 21.5:1, Marine 18:1 |
| Turbocharger | Borg-Warner GM-X series, also available naturally aspirated |
| Fuel system | 1993 And older-Mechanical rotary pump. 1994 And newer-Electronic rotary pump |
| Fuel type | Diesel |
General Motors introduced a line of Diesel V8 engine engines for their C/K pickup trucks in 1982. This engine family, designed by GM division Detroit Diesel, was produced by GM through 2000, when it was replaced by the new Duramax line. AM General's subsidiary General Engine Products (GEP) still produces a military variant of this engine for the HMMWV.[1]
The General Motors light-truck 6.2 and 6.5 L Diesel engines were optional in all 1982 through 2000 Chevrolet and GMC C/K series pickup trucks, Suburbans, Blazer/Jimmy, Tahoe/Yukon, vans, and motor homes. The engine was standard on AM General HMMWV, Hummer H1 and Commercial Utility Cargo Vehicle vehicles. The ready availability and low cost of these engines has made them popular for conversion projects and kit vehicles. These engines are often a popular choice for conversion in Land Rovers, Land Cruisers, and similar vehicles.
Contents |
The original 6.2 L (379 cu in) Diesel V8 was introduced in 1982 for the Chevrolet/GMC C/K trucks and was produced until 1993. The 6.2L diesel emerged as a high-MPG alternative to the V8 gasoline engine lineup, and achieved better mileage than the General Motors 4.3L V6 gasoline engines of the 80s, at a time when the market was focused on mileage more than power.
The 6.5 L (395 cu in) version was introduced in 1992 to replace the 6.2. Most 6.5s are equipped with a turbo. This engine was never meant to be a power and torque competitor with Ford/International and Dodge/Cummins, but rather a simple designed workhorse engine that made credible power, achieved decent fuel economy and met emissions standards in half-ton trucks. The Duramax 6600 replaced the 6.5 in light trucks beginning in 2001 and the C3500HD medium duty cab and chassis (replaced by C4500 Kodiak/Topkick) and vans beginning in 2003, but the 6.5 (6500 Optimizer) is still produced by AM General for the HMMWV.
There are several GM 6.5 liter diesel engine production options. The Turbocharged L56, (VIN "S") was used in most 1/2 ton (1500) and light duty 3/4 ton (2500) trucks. One percent of the 1/2 ton (1500) contained a naturally aspirated version of the 6.5. Heavy duty 3/4 ton and 1 ton trucks used the Turbocharged L65 (VIN "F") engine. The L56 is emissions controlled with EGR and catalytic converters. The L65 engine has no EGR, and has no catalytic converter. There is a soot trap on L65 engines that is often mistaken for a catalytic converter. The L49 (VIN "P") and L57 are both naturally aspirated engines. L57 is listed as HO or Heavy Duty. Additional RPO codes are LQM (175HP) and LQN (190HP).
Changes were made by GM to the 6.5 in their light trucks for emissions or reliability improvement. The 1992-1993 model years used a 6.5-specific Stanadyne DB-2 mechanical injection pump. GM replaced the DB-2 with the electronic throttle DS-4 in 1994-2000 vehicles. In mid-1996 GM implemented a redesigned engine cooling system incorporating twin non bypass-blocking thermostats and a 130 GPM water pump. This improved the flow through the block by 70-75% and flow to the radiator 7%.
The fuel system on both of these engines relies on a very basic setup. On the 6.2L engines, a camshaft driven mechanical lift pump draws fuel from the tank to the injection pump (also camshaft driven). On 6.5L engines, the lift pump is electrically powered. The injection pump delivers fuel precisely as the injectors need to fire correctly. The fuel system uses Indirect injection and, on 1982-1993 engines, is completely mechanical, much like the Ford 6.9 & 7.3 International Harvester IDI fuel system utilizes. The 1994+ system is similar, but uses the electronically controlled Stanadyne DS4831 series of injection pumps instead of the mechanical DB2831 series found on 1992-1993 6.5's and the DB2829 found on 6.2's.