TURBOCHARGER COOLING LINE CHANGE (DESCRIPTION AND USAGE)

TURBOCHARGER COOLING LINE , SIZE DIFFERENCES

VEHICLES AFFECTED 1987-88 J AND N CARS W/2.0L ----------------- (INFORMATION ONLY)

During the mid-1988 model year, the L-4 turbocharger applications changed the size and material of the turbo water feed pipe. The feed pipe diameter reduction change (1/2" to 5/16") does not impact turbo cooling efficiency; however, the pipe material change (stainless to carbon steel) improves sealing ability after any repair in this area.

For 1988 vehicles, the turbo cooling feed pipe from thermostat to turbo center housing should be checked for size before ordering any parts from GMSPO. The 1987 L0512-4 turbocharger system uses the 1/2" cooling line, but it can be serviced with the mid 1988 5/16" line other parts, if improved coolant line sealing is necessary.

Following is a detailed breakdown of the specific parts required:

1/2" 1987 and Early 1988 ------------------------ - Thermostat Housing Assembly - P/N 10045025

- Housing attachment torque is 12-18 Nm (9-13 ft. lb.)

- Turbo Coolant Feed Hose Assembly - P/N 10045022

- 1/2" line nut torque is 40-50 Nm (29-37 ft. lb.)

5/16" Mid-1988 System and 1988/87 Back Service Group ---------------------------------------------------- - Thermostat Housing Assembly - P/N 10116222 - Thermostat Housing Gasket - P/N 10103540

- Housing attachment torque is 12-18 Nm (9-13 ft. lb.).

- 5/16" Turbo Coolant Feed Pipe Assembly - P/N 10068531

- 5/16" line nut torque is 15-20 Nm (11-16 ft. lb.).

- 5/16" Turbo Center Housing Fitting - P/N 10121014

- Fitting install torque is 30-45 Nm (22-33 ft. lb.).

General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.