6.5L
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 simply 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 light duty 3/4 ton (2500). 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. GM was the first manufacturer to introduce an electronically controlled fuel injection system into a diesel pickup truck.[2] 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%.
Applications[edit]
(6.5 diesel only)
1994 - 1999 Chevy Blazer/ 2-door Tahoe / GMC Yukon/Chevy K-2500, K-3500
1994 - 1999 Chevrolet Suburban / GMC Suburban
1992 - 1999 Chevrolet and GMC C/K
2000 Chevrolet and GMC C/K 2500 & 3500
2001 Chevrolet and GMC C/K 3500
1994 - 2004 AM General Hummer H1
1994–present AM General HMMWV
Specifications[edit]
Engine RPO Codes: L49, L56, L57, L65, LQM, and LQN.
Displacement: 6.5L / 395 cu in
Bore x Stroke: 4.06 x 3.82 (in.)
Block / Head: Cast iron / Cast iron
Aspiration: Turbocharged (Borg-Warner GM-X series) Also available naturally aspirated.
Valvetrain: OHV 2-V
Compression: GM Early 21.3:1, GM Late 20.3:1, AMG/GEP Marine 18:1
Injection: Indirect
Power / Torque (lowest): 155 hp (116 kW) @ 3,600 rpm / 340 lb·ft (461 N·m) @ 1,700 rpm (naturally aspirated)
Power / Torque (highest): 215 hp (160 kW) @ 3,200 rpm / 440 lb·ft (597 N·m) @ 1,800 rpm (turbocharged)[1]
Max RPMs: 4,200