General Engine Service Procedures
Torque Values and/or Fastener Tightening Strategies- Cylinder head bolts, the crankshaft bearing cap bolts, and the connecting rod bolts apply a torque angle strategy.
- In an on-vehicle situation where a torque angle meter may not fit into the vehicle packaging, a three step tightening process may be followed using a torque wrench.
- Certain fasteners should not be reused. Bolts, studs, or other fasteners that must be replaced will be called out in the specific service procedure.
Disassembly and Assembly Procedure
- Discard all used gaskets, seals, or O-ring seals unless otherwise indicated.
- Gaskets, seals, or O-ring seals that can be reused will be identified in the specific service procedure.
Thread Repair
Tools Required
General purpose thread repair kits. These kits are available commercially.
Caution: Wear safety glasses in order to avoid eye damage.
Important:
Refer to the kit manufacturer's instructions regarding the size of the drill and which tap to use.
Avoid any buildup of chips. Back out the tap every few turns and remove the chips.
1. Determine the size, the pitch, and the depth of the damaged thread.
Adjust the stop collars on the cutting tool as needed. Tap the collars to the required depth.
2. Drill out the damaged thread. Clean out any chips.
3. Tap the hole. Lubricate the tap with light engine oil. Clean the thread.
4. Thread the insert onto the mandrel of the installer. Engage the tang of the insert onto the end of the mandrel.
Important: The insert should be flush to I turn below the surface.
5. Lubricate the insert with light engine oil (except when installing in aluminum) and install the insert.
6. If the tang of the insert does not break oft when backing out the installer, break off the tang using a drift punch.
Cleanliness and Care
- Throughout these procedures, it should be understood that proper cleaning and protection of machined surfaces and friction areas is part of the repair procedure. This is considered standard shop practice even if not specifically stated.
- When any internal engine parts are serviced, care and cleanliness is important.
- When components are removed for service, the components should be marked, organized or retained in a specific order for re-assembly.
- At the time of installation, the components should be installed in the same location and with the same mating surface as when removed.
- An automobile engine is a combination of many machined, honed, polished and lapped surfaces with tolerances that are measured in millimeters or thousandths of an inch. The surfaces should be protected to avoid component damage.
- Apply a liberal amount of clean engine oil to friction areas during assembly.
- Proper lubrication will protect and lubricate friction areas during initial operation.
Replacing Engine Gaskets
Gasket Reuse and Applying Sealant
- Do not reuse any gasket unless specified.
- Gaskets that can be reused will be identified in the service procedure.
- Do not apply sealant to any gasket or sealing surface unless specified in the service procedure.
Separating Components
- Use a rubber mallet in order to separate the components.
- Bump the part sideways in order to loosen the components.
- Bumping of the component should be done at bends or reinforced areas of the component to prevent distortion of the components.
Cleaning Gasket Surfaces
- Use care to avoid gouging or scraping the sealing surfaces.
- Use a plastic or wood scraper in order to remove all the sealant from the components.
- Do not use any other method or technique to remove the sealant or the gasket material from a part.
- Do not use abrasive pads, sand paper, or power tools to clean the gasket surfaces.
- These methods of cleaning can cause damage to the component seedling surfaces.
- Abrasive pads also produce a fine grit that the oil filter cannot remove from the engine oil.
This fine grit is an abrasive and can cause internal engine damage.
Assembling Components
- Assemble components using only the sealant (or equivalent) that is specified in the service procedure.
- Sealing surfaces must be clean and free of debris or oil.
- Specific components such as crankshaft oil seals or valve stem oil seals may require lubrication during assembly.
- Components requiring lubrication will be identified in the service procedure.
- Apply only the amount of sealant specified in the service procedure to a component.
- Do not allow the sealant to enter into any blind threaded holes, as the sealant may prevent the fastener from clamping properly or cause component damage when tightened.
- Tighten fasteners to the proper specifications. DO NOT overtighten the fasteners.
Use of RTV and Anaerobic Sealer
Important: The correct sealant and amount of sealant must be used in the proper location to prevent oil leaks, coolant leaks, or the loosening of the fasteners. DO NOT interchange the sealants. Use only the sealant (or equivalent) as specified in the service procedure.
The following 2 major types of sealant are commonly used in engines:
- Aerobic sealant (Room Temperature Vulcanizing (RTV))
- Anaerobic sealant, which include the following:
- Gasket eliminator
- Pipe
- Threadlock
Aerobic Type Room Temperature Vulcanizing (RTV) Sealant
Aerobic type Room Temperature Vulcanizing (RTV) sealant cures when exposed to air. This type of sealant is used where 2 components (such as the intake manifold and the engine block) are assembled together.
Use the following information when using RTV sealant:
- Do not use RTV sealant in areas where extreme temperatures are expected. These areas include:
- The exhaust manifold
- The head gasket
- Any other surfaces where a different type of sealant is specified in the service procedure
- Always follow all the safety recommendations and the directions that are on the RTV sealant container.
- Use a plastic or wood scraper in order to remove all the RTV sealant from the components.
Important: Do not allow the RTV sealant to enter any blind threaded holes, as it may prevent the fasteners from clamping properly or cause damage when the fastener is tightened.
- The surfaces to be sealed must be clean and dry.
- Use a RTV sealant bead size as specified in the service procedure.
- Apply the RTV sealant bead to the inside of any bolt holes areas.
- Assemble the components while the RTV sealant is still wet to the touch (within 3 minutes). Do not wait for the RTV sealant to skin over.
- Tighten the fasteners in sequence (if specified) and to the proper torque specifications. DO NOT overtighten the fasteners.
Anaerobic Type Gasket Eliminator Sealant
Anaerobic type gasket eliminator sealant cures in the absence of air. This type of sealant is used where 2 rigid parts (such as castings) are assembled together. When 2 rigid parts are disassembled and no sealant or gasket is readily noticeable, then the 2 parts were probably assembled using an an aerobic type gasket eliminator sealant.
Use the following information when using gasket eliminator sealant:
- Always follow all the safety recommendations and directions that are on the gasket eliminator sealant container.
- Apply a continuous bead of gasket eliminator sealant to one flange. The surfaces to be sealed must be clean and dry.
Important: Do not allow the gasket eliminator sealant to enter any blind threaded holes, as the gasket eliminator sealant may prevent the fasteners from clamping properly, seating properly, or cause damage when the fastener tightened.
- Apply the gasket eliminator sealant evenly to get a uniform thickness of the gasket eliminator sealant on the sealing surface.
Important: Gasket eliminator sealed joint fasteners that are partially torqued and the gasket eliminator sealant allowed to cure more than five minutes, may result in incorrect shimming and sealing of the joint.
- Tighten the fasteners in sequence (if specified) and to the proper torque specifications. DO NOT overtighten the fasteners.
- After properly tightening the fasteners, remove the excess gasket eliminator sealant from the outside of the joint.
Anaerobic Type Threadlock Sealant
Anaerobic type threadlock sealant cures in the absence of air. This type of sealant is used for threadlocking and sealing of bolts, fittings,nuts, and studs. This type of sealant cures only when confined between 2 close fitting metal surfaces.
Use the following information when using threadlock sealant:
- Always follow all safety recommendations and directions that are on the threadlock sealant container.
- The threaded surfaces to be sealed must be clean and dry.
- Apply the threadlock sealant as specified on the threadlock sealant container.
Important: Fasteners that are partially torqued and then the threadlock sealant allowed to cure more than five minutes, may result in incorrect clamp load of assembled components.
- Tighten the fasteners in sequence (if specified) and to the proper torque specifications. DO NOT overtighten the fasteners.
Anaerobic Type Pipe Sealant
Anaerobic type pipe sealant cures in the absence of air and remains pliable when cured. This type of sealant is used where 2 parts are assembled together and require a leak proof joint.
Use the following information when using pipe sealant:
- Do not use pipe sealant in areas where extreme temperatures are expected. These areas include:
- The exhaust manifold
- The head gasket
- Surfaces where a different sealant is specified
- Always follow all the safety recommendations and the directions that are on the pipe sealant container.
- The surfaces to be sealed must be clean and dry.
- Use a pipe sealant bead of the size or quantity as specified in the service procedure.
Important: Do not allow the pipe sealant to enter any of the blind threaded holes, as the pipe sealant may prevent the fastener from clamping properly, or cause component damage when the fastener is tightened.
- Apply the pipe sealant bead to the inside of any bolt hole areas.
- Apply a continuous bead of pipe sealant to 1 sealing surface.
- Tighten the fasteners in sequence (if specified) and to the proper torque specifications. DO NOT overtighten the fasteners.
Separating Parts
Important:
Many internal engine components will develop specific wear patterns on their friction surfaces.
When disassembling the engine, internal components MUST be separated, marked and organized in a way to ensure reinstallation to original location and position.
Mark or identify the following components:
- Piston and the piston pin
- Piston to the specific cylinder bore
- Piston rings to the specific cylinder bore
- Connecting rod to the crankshaft journal
- Connecting rod to connecting rod cap
- Crankshaft bearings and connecting rod bearings
- Engine camshaft and valve lifters
- Valve lifters and valve rocker arms
- Valve to the valve guide
- Valve spring to cylinder head location
- Engine block bearing cap location and direction
- Oil pump drive and driven gears