Various 4-140 engines have have been modified to accept an exhaust driven turbocharger, providing increases in both horsepower and torque over normally aspirated engines. As an on-demand system, the turbocharger boosts engine output at high load/high speed conditions, while having little effect on fuel economy at moderate to light load conditions.
The turbocharger, which is mounted on the right side of the engine, consists of five major components. These include the compressor, the center housing, the outlet elbow and wastegate, the turbine and the wastegate actuator.
The turbocharger is serviced by replacement only.
REMOVAL & INSTALLATION
See Figures 1 and 2
Before starting removal/service procedures, clean the area around the turbocharger with a non-caustic solution. Cover the openings of component connections to prevent the entry of dirt and foreign materials. Exercise care when handling the turbocharger so as not to nick, bend or in any way damage the compressor wheel blades.
- Disconnect the negative battery cable.
- Drain the cooling system.
- Loosen the upper clamp on the turbocharger inlet hose. Remove the two bolts mounting the throttle body discharge tube to the turbocharger.
- Label for identification and location all vacuum hoses and tubes to the turbo and disconnect them.
- Disconnect the PCV tube from the turbo air inlet elbow. Remove the throttle busy discharge tube and hose as an assembly.
- Disconnect the ground wire from the air inlet elbow. Remove (disconnect) the water outlet connection (and fitting, if a new turbo unit is to be installed) from the turbo center housing.
- Remove the turbo oil supply feed line. Disconnect the oxygen sensor connector at the turbocharger.
- Raise and support the front of the vehicle on jackstands. Disconnect the exhaust pipe from the turbocharger.
- Disconnect the oil return line from the bottom of the turbocharger. Take care not to damage or kink the line.
- Disconnect the water inlet tube at the turbo center housing.
- Remove the lower turbo mounting bracket-to-engine bolt. Lower the vehicle from the jackstands.
- Remove the lower front mounting nut. Remove the three remaining mounting nuts while simultaneously sliding the turbocharger away from its mounting studs.
- Position a new turbocharger mounting gasket in position with the bead side facing outward. Install the turbocharger in position over the four mounting studs.
- Position the lower mounting bracket over the two bottom studs. Start the two lower, then the two upper retaining nuts. Do not tighten them completely at this time, to allow for slight turbo movement.
- Raise and support the front of the vehicle on jackstands.
- Connect the water inlet tube assembly.
- Install a new oil return line gasket and connect the return line to the turbocharger. Tighten the mounting bolts to 14-21 ft. lbs.
- Connect the exhaust pipe to the turbocharger and tighten the retaining nuts to 25-35 ft. lbs.
- Lower the vehicle. Using four new nuts, tighten the turbocharger-to exhaust manifold mounting nuts to 28-40 ft. lbs.
- Connect the water outlet assembly to the turbocharger, tighten the fasteners to 11-14 ft. lbs. Hold the fitting with a wrench when tightening the line.
- Install the air inlet tube to the turbo inlet elbow and tighten the bolts to 15-22 ft. lbs. Tighten the hose clamp to 15-22 inch lbs. .
- Connect the PCV tube and all vacuum lines.
- Connect the oxygen sensor and other wiring which was disconnected.
- Install the oil supply line and the air intake tube.
- Fill the cooling system and connect the negative battery cable.
- Start the engine and check for coolant leaks. Check vehicle operation.