Engine Removal (Automobile)

Engine Service

The engine requires disassembly for internal service when adjustment and repair of the engine accessories do not correct the engine problem. Engine problems requir­ing upper engine service are primarily confined to the valve train (except for the cam), gaskets, and cracks that develop in the manifolds and heads. Valve-train problems are usually evident as noise. Valve problems lead to loss of compression. Gasket problems and cracks lead to loss of compression. Often, these problems are identified during a tune-up.
The most common reason for servicing the lower end of the engine is to replace the rings and recondition the pistons. This is usually accompanied by replacement of the connecting rod bearings. It is customary to service the valve train whenever the head is removed, and this is usually carried out at the same time. Servicing the rings and doing a valve job reseal the combustion chamber so that the engine restores high compression once again, which allows the engine to produce its normal power. The ring and valve job generally reduce oil consumption. The other reasons for servicing the lower end of the engine include loss of oil pressure, abnormal sound, bearing knock, and breakage of parts. In some cases, the engine is disassembled and serviced as a high-mileage routine maintenance job to head off any serious damage.
Lower-engine service can be classified as an overhaul or a rebuild. An engine is considered as rebuilt when it has been completely disassembled and all parts are brought back to the specifications of a new engine. Engine rebuilding requires an automotive machine shop.
This chapter discusses the upper and lower-engine services. The lower engine service is limited to the engine overhaul rather than to rebuilt. An overhaul can often be carried out with typical shop tools. Only those parts requiring a specialized service are taken to the automobile machine shop. Upper-engine service helps determine if the lower end requires service.
20.1.


Engine Removal

The engine heads and manifolds can be removed with the engine in the chassis. In some models, the oil pan can also be dismantled with the engine in the chassis. The engine has to be removed from the chassis of most domestic vehicles for performing lower-engine service. In this situation, the manifolds and heads are not removed until the engine is out of the chassis as this makes disassembly much easier.
The engine can be removed in two ways. This can be lifted out of the chassis with the transmission attached or the transmission can be detached from the engine and left in the chassis. In the following discussion, it is considered that the engine is removed for overhaul with the transmission attached.

The battery is removed first to avoid sparks and spilling of acid. It is much easier to work on the engine if the engine compartment is steam cleaned. The engine oil and coolants are drained and examined for their condition before discarding. With fender covers in place, the hood is removed as described in section 20.2.1. All coolant hoses are removed and the transmis­sion oil cooler lines disconnected from the radiator. The radiator mounting bolts are removed and the radiator is lifted from the engine compartment. This is a right time to clean the radiator when it is out of the chassis during engine overhaul. If it does not require cleaning, it is placed safely to avoid damage as the overhaul progresses. The automobile trunk provides a good storage place for the radiator.
With an air-conditioned engine, the compressor can normally be removed from the engine, leaving all air conditioning hoses securely connected to the compressor and lines. This compres­sor can be secured at the side of the engine compartment without interfering with engine removal. It may also be necessary to loosen the condenser and fasten it aside. In case it is necessary to disconnect the air conditioning lines the system has to be bled down, following the procedure described in chapter 33, before dismantling the system. All openings should be securely plugged immediately to avoid entering of dirt and moisture into the system. They should remain plugged until just before reassembly. The air conditioning system requires evacuation and recharging once it is reassembled after completion of overhauling.
All wires, hoses, tubing, and controls connected to the engine are tagged for location before disconnecting. This causes the reassembly easier after overhaul. It is a good practice to remove the distributor, carburettor, alternator, and fan to avoid accidental damage during engine removal. It is also a good practice to recondition these units while the engine is being overhauled so that the finished engine performs satisfactorily and operates trouble free for a long time.
Under the car, the propeller shaft is removed and the exhaust pipe is disconnected. In some installations it is necessary to loosen the steering linkage idler arm to provide sufficient clearance. The transmission controls, speedometer cable, and clutch linkages are disconnected and tagged. These are properly secured so that they are out of damage during removal of the engine. The automatic transmission cooling lines and the starter wires are removed.
The engine has three mounts, one on each side and one at the back of the transmission. The mount bolts are removed so that the engine rests on the mounts. A sling, either a chain or lift cable, is attached to manifold or head cap screws on top of the engine. A hoist is attached to the sling and snugged to take up most of the weight. The rear cross member is removed and the transmission is lowered. The hoist is tightened to lift the engine. The engine noses up as it is removed with the front of the engine coming almost straight up while the transmission slides from under the floor pan (Fig. 20.1). The engine and transmission are hoisted free of the vehicle, swung clear and lowered on an open floor area. Blocks are placed under the engine to make it steady. The hoist is loosened, but kept attached to the engine as a safety measure until the transmission is removed.
Engine with the transmission attached being lifted from the chassis.
Fig. 20.1. Engine with the transmission attached being lifted from the chassis.
A thorough visual examination of the exterior of the engine should be hold before taking up any other work. After identifying any fluid leaks and obvious faults, the exterior of the engine should be thoroughly cleaned. Steam cleaning is recommended to clean the exterior of the engine.

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