All instructions given assume that the engine has been removed from the vehicle. Information regarding the repair of the engine in the engine compartment, as well as regarding the removal and installation of external engine components, is given in Chapter Engine repair and in Section Dismantling of a head of the block of cylinders from this Part.
General description of the engine bulkhead
It is not always easy to determine if an engine needs to be overhauled. it depends on many factors.
High mileage does not necessarily mean that a bulkhead is needed, and vice versa, low mileage does not eliminate the need for it. Maintenance frequency is the most important factor to take into account. An engine that has its oil and filter changed regularly, and other required maintenance performed, will reliably last for many thousands of miles. Conversely, a poorly maintained engine may require overhaul at very high mileage.
Excessive oil consumption indicates that the piston rings, valve stem seals and / or their guide bushings are damaged (however, the possibility of leaks must first be ruled out). Perform a compression test to determine the probable cause of excessive lubricant consumption.
Check the oil pressure by setting the measuring device to the working position of the oil pressure sensor, and compare the result with the data specified in the Specifications. If this pressure is low, the main and connecting rod bearings and/or the oil pump are probably worn out.
Loss of power, erratic engine operation, engine or valvetrain noises, and high fuel consumption may also mean that the engine needs to be overhauled, especially if all of these factors are present at the same time. If a full course of maintenance has not corrected the problem, regrinding worn components is the only solution.
An engine overhaul involves the restoration of all internal parts, the replacement of pistons and piston rings. As a rule, new liners of main and connecting rod bearings are installed; if necessary, the crankshaft can be replaced or reground; in addition, valves are serviced. When overhauling the engine, the bulkhead can also be tucked in components such as a starter and generator.
Note. When overhauling the engine, replace the cooling system hoses, thermostat and water pump. Carefully inspect the radiator to make sure it is not clogged or leaking. In addition, it is recommended to replace the oil pump.
Before proceeding with the overhaul of the engine, read the description of all procedures and prepare everything necessary. If you carefully follow all the instructions and prepare the necessary tools and equipment, the work will not cause any particular difficulties, although it may take a long time. Check if the required spare parts are available. Most of the work can be done with ordinary tools, but precision measuring tools are required to inspect parts and determine if they need to be replaced.
Note. Before deciding which repair procedures should be performed, the engine must be completely disassembled and all components inspected (especially the cylinder block and crankshaft). The condition of these components is the main factor that determines whether an engine overhaul is possible or whether it should be replaced with a rebuild unit. Do not buy parts or repair any components until you have made this decision.