• A rebuilt engine is an overhaul which is different than engine service. The wear items of an engine are replaced components are cleaned, inspected and replaced or reconditioned as needed. Understanding the steps in an overhaul is the best way to understand what a rebuilt engine is. Depending on the particular engine, additional steps may be commonly required to be considered rebuilt.


    The engine is disconnected, all fluids are drained and properly disposed. Accessories like the alternator or fans are removed. The engine is disconnected from the transmission and body.


    Once the engine has been removed, it is disassembled into component parts. The manifold and oil pan are disconnected from the block. The internal parts are removed, organized and inventoried.

    Cleaning And Inspection

    Once disassembled, all the components are thoroughly cleaned. The block is degreased, all gaskets are removed and discarded along with the o-rings and seals. Once clean, the parts are thoroughly inspected. For example: piston heads are inspected and measured and replaced if out of specification. Rods are checked for wear.

    Reassembly And Testing

    Next the engine is reassembled. New o-rings, seals and gaskets are installed. The timing is checked to factory specifications. Fluids are replaced and the engine is run to check for performance and leaks. If everything checks out, the engine is reinstalled.

    Practical Improvements

    Practically, an owner should expect to see horsepower improvement similar to when the engine was new, as well as improvement in fuel efficiency and vehicle emissions. Any leaks or excessive use of oil should also be corrected.


    NASA: 4-Stroke Internal Combustion Engine

    Twin Turbo Zs of Dallas: Engine Removal

    Engine Repower Council

    More Information:

    Auto Zone

Copyright 2020, Wired Ivy, LLC

Answerbag | Terms of Service | Privacy Policy