New Product Information. GMC Truck GMC C-Series Medium Duty Truck B7 1999

For 1990-2009 cars only

Makes 🢒 GMC_Truck 🢒 1999 🢒 GMC C-Series Medium Duty Truck B7 🢒 Engine 🢒 Engine Mechanical - 7.4L 🢒 New Product Information

The purpose of New Product Information is to highlight important technical changes from the previous model year.

Changes may include one or more of the following items:

•	Torque values and/or fastener tightening strategies

•	Changed engine specifications

•	New sealants and/or adhesives

•	Disassembly and assembly procedure revisions

•	Engine mechanical diagnostic procedure revisions

•	New special tools required

•	A component comparison from the previous year

•	Cylinder head bolts now apply a torque angle strategy.

•	Certain fasteners should not be reused. Bolts, studs, or other fasteners that must be replaced will be called out in the specific service procedure. Refer to Fastener Tightening Specifications and Engine Mechanical Specifications .

•	Base Engine Misfire, Valve Train, and other diagnostic information is now provided in table form.

•	Potential or probable causes are supplied for each specific concern.

•	The 1998 6.0 liter LS0 or 7.0 liter LR0 engine has been replaced by the new 1999 7.4 liter LP4 or L21 engine. The new features include a distributorless ignition system:

-	Crankshaft position sensor and reluctor ring

-	Camshaft position sensor

-	Eight individual ignition coils

•	Refer to Disassembled Views and Engine Component Description .