Gasoline Engines - Repair Procedures Without Engine Removal from Vehicle

This subsection describes repair procedures that can be performed on the engine while it remains installed in the vehicle. Subsection 3.1.2 describes the removal and installation of the engine assembly from the vehicle and all major overhaul work on the cylinder block and cylinder head.
All repair operations described below assume that the engine has not been removed from the vehicle. If the engine has been removed and mounted on a stand, many of the disassembly operations described in this subsection are not required.
The data in this subsection apply only to the procedures described in this same part. Subsection 3.1.2.1 contains the specifications required for repair of the cylinder block and cylinder head.
Engines installed in Corolla vehicles of those years are designated 4E-FE (1.3 L), 4A-FE (1.6 L) and 7A-FE (1.8 L). All three engines have almost identical design: 16-valve, with two camshafts and overhead valves.
Repair operations possible without removing the engine from the vehicle
Many major repair operations can be performed without removing the engine from the vehicle.
Before starting any work, it is highly recommended to clean the engine compartment and engine with an engine cleaner. Working on a clean engine is easier, and dirt is prevented from entering the engine.
To remove certain parts and assemblies and to increase working space, it may be necessary to remove the hood.
To avoid damaging the finish, cover the bumpers. Protective covers will be needed for the work; old cots or blankets are suitable.
If there is evidence of leakage in the vacuum lines, exhaust system, or cooling system indicating the need to replace gaskets, the repair can, as a rule, be performed without removing the engine. Without removal, the intake and exhaust manifold gaskets, oil pan gasket, cylinder head, and crankshaft oil seals can be replaced.
Without removing the engine from the vehicle, the following attached components can be removed: intake and exhaust manifolds, oil pan, oil pump, coolant pump, starter motor, alternator, ignition distributor, and fuel system components. However, to remove the oil pump, it is necessary to raise the engine and remove the right engine mount.
Since the cylinder head can also be removed without removing the engine, it is also possible to perform repair or replacement of the camshaft, valves, and their drive components. Without removal, it is also possible to perform operations such as replacing or inspecting the timing belt, camshaft drive gears, and pulleys.
In extreme cases, when the necessary equipment is not available, piston rings, pistons, connecting rods, and connecting rod bearings can be replaced without removing the engine. However, performing these operations without removing and fully disassembling the engine is strongly not recommended, since cleaning of related parts and preparatory assembly measures are required.