Engine Removal and
Disassembly
Chapter 50
© © 2012 Delmar, Cengage Learning
Objectives
• Label and organize parts prior to engine
removal
• Remove an engine from a vehicle in a safe and
methodical manner
• Disassemble the engine following the correct
procedures
• Keep parts organized for reassembly
• Inspect and interpret causes internal engine
wear
© © 2012 Delmar, Cengage Learning
Introduction
• Procedures must be followed carefully
– Parts must be removed and inspected in an
orderly manner
• You cannot hurry
• Signs of wear can be clues
• Correct repair will prevent the problem from
occurring again
– Be sure to consult the applicable repair manual
• Procedures differ
© © 2012 Delmar, Cengage Learning
Engine Removal
• Important steps
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Disconnect battery cables
Remove the hood
Remove air cleaner
Label all wires and vacuum lines
Drain coolant and oil
Remove the radiator
Remove the distributor and spark plug wiring
Remove the direct current (DC) generator
Remove the heater hoses and ground strap
© © 2012 Delmar, Cengage Learning
© © 2012 Delmar, Cengage Learning
© © 2012 Delmar, Cengage Learning
Engine Removal (cont'd.)
– Remove switches and sensors
– Remove the throttle linkage, cable, or wiring
– Mark accessory brackets and remove
accessories
– Remove exhaust components
– Remove and plug the fuel line
– Determine whether to remove the transmission
– Separate the engine and transmission/transaxle
– Unbolt the engine mounts
© © 2012 Delmar, Cengage Learning
© © 2012 Delmar, Cengage Learning
Engine Removal (cont'd.)
– Remove the engine from the vehicle
– Remove transaxle (if necessary)
• Remove lower ball joints
– Have drain pan ready
• Disconnect speedometer cable, transmission shift
linkage, and clutch cable
• Attach a sling to the engine and transaxle assembly
• Remove bolts
• Roll shop crane until the engine can be lowered
safely
© © 2012 Delmar, Cengage Learning
Engine Disassembly
• Important steps
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Remove clutch parts
Remove hybrid armature (puller required)
Mount engine to a stand
Remove coolant pump
Remove oil pan
Remove valve covers
• Slip a knife blade between head and sheet metal
valve cover
• Tap a curved, strong area with a rubber mallet
© © 2012 Delmar, Cengage Learning
Engines with Pushrods
• Stud mounted rockers
– Loosen nuts on studs before disassembly and
cleaning
– Turn rocker arms to the side to remove the
pushrods
– After heads are cleaned they can be removed
one at a time
– Keep pushrods in order
© © 2012 Delmar, Cengage Learning
Engines with Pushrods (cont'd.)
• Shaft-mounted rockers
– Should be loosened slowly and evenly
– Remove the pushrods
– Pushrods can be pushed through holes made in
a piece of cardboard
– Pushrods must be kept in order
© © 2012 Delmar, Cengage Learning
Engines with Pushrods (cont'd.)
• Valve lifters
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Remove valve lifters
Wipe oil off bottom of lifters
Label with a felt marker
Reused flat tappers must be used on original
cam lobe
• Usually replaced
– Roller lifters are usually reusable
– Use chemical cleaner to soften varnish
© © 2012 Delmar, Cengage Learning
© © 2012 Delmar, Cengage Learning
© © 2012 Delmar, Cengage Learning
Engines with Pushrods (cont'd.)
• Pushrod engine camshaft
– Some pushrod engines use bolt-on cam thrust
plate
– Varnish may builds up on edges of cam journals
• Makes it difficult to remove the cam
• Vibration damper removal
– Most engines have a bolt that holds it on the
crankshaft
• Some will slip off after the bolt is removed
– Others are pressed-fit
© © 2012 Delmar, Cengage Learning
Overhead Cam Cylinder Head
Removal
• Important steps
– Position the number one piston at TDC and note
the location of timing marks
– Compare the sketch in the repair manual to the
marks on the timing belt
– Draw a sketch of the cam timing
– Remove timing cover
© © 2012 Delmar, Cengage Learning
© © 2012 Delmar, Cengage Learning
Overhead Cam Engines
(cont'd.)
– Remove the cam drive assembly
• Pushrod engines
– Unbolt cam sprocket and slide or pry off the cam
– Remove the chain
– Reinstall sprocket and tighten one bolt finger tight
• Overhead cam engines
– Remove the chain or bolt tensioner
© © 2012 Delmar, Cengage Learning
© © 2012 Delmar, Cengage Learning
Overhead Cam Engines
(cont'd.)
– Remove the cylinder heads
• Mark one of the cylinder heads “left” or “right” if
there is more than one
• Be careful not to break a casting
– Inspect the head gasket
• Evidence of coolant or oil leakage
• Signs of detonation
© © 2012 Delmar, Cengage Learning
Cylinder Block Disassembly
• Modern engines use premium piston rings
– Will not accommodate a worn cylinder bore
• Ridge causes
– Pressure of combustion forcing the piston ring
against the cylinder wall
– Lack of clean lubrication at the top of the cylinder
© © 2012 Delmar, Cengage Learning
Cylinder Block Disassembly
(cont'd.)
• Important steps
– Turn engine over and mark main caps and rod
caps
– Main caps must be installed in one direction only
– Connecting rods and caps are mated to one
another and must be marked for identification
– Remove and inspect the piston and rod assembly
– Inspect the piston, rings, rod, and bearings
– Remove the crankshaft and inspect for wear
– Remove the camshaft
© © 2012 Delmar, Cengage Learning
© © 2012 Delmar, Cengage Learning
Cylinder Block Disassembly
(cont'd.)
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Remove and label cam bearings
Remove core plugs
Clean engine parts
Remove the crank sprocket or gear
Finish diagnosis and repair of engine assembly
© © 2012 Delmar, Cengage Learning