Before starting any repair work, clean the vehicle's engine compartment and engine housing with a suitable detergent. This will facilitate the work and prevent dirt from entering the engine.
Depending on what parts you will have to deal with during the repair work, it may be useful to remove the hood to free access to them (if necessary, contact chapter 11, section 9).
If the cooling system or exhaust system is leaking, indicating the need to replace gaskets or seals, it is generally possible to repair without removing the engine from the vehicle. Gaskets on the intake and exhaust manifolds, oil sump and cylinder head are accessible without removing the engine from the vehicle.
External engine parts such as intake and exhaust manifolds, oil pan and oil pump, coolant pump, starter motor, alternator and fuel injection units can be repaired without removing the engine from the vehicle.
Because the cylinder heads can be removed with the engine installed, timing parts can also be replaced with the engine not removed from the vehicle.
In extreme cases, due to the lack of necessary equipment, it is possible to repair or replace piston rings, pistons, connecting rods and connecting rod bearings with the engine not removed. However, this practice is not recommended due to the need to perform cleaning and preparation of these parts.