Serpentine Belt Installation on a Buick 3.8 Liter

by Mark Robinson

The Buick 3.8-liter engine was produced by General Motors from 1975 to 2008, with several fundamental changes made to it over the course of its lifetime. In 1985, the 3.8-liter engine came equipped with a serpentine belt system to drive the engine accessories. This engine was used in a number of GM vehicles, including the Pontiac Bonneville, Buick Regal and Oldsmobile 88 and 98. The serpentine belt should be checked every 5,000 or 6,000 miles for signs of wear or damage.

Disconnect the negative terminal cable from the battery. Locate the belt routing diagram within the engine bay. If a diagram is not present, consult the owner's manual for the belt routing diagram.

Locate the belt tensioner pulley between the power steering pump and alternator. Place a socket and ratchet on the 15mm bolt located on the tensioner pulley and move the pulley up and away from the belt. Slip off the belt from the tensioner pulley and slowly release the tensioner back into position.

Remove the belt from the other pulleys. Compare the new serpentine belt to the old belt to ensure it is roughly the same size and type.

Route the new belt onto the other pulleys according to the belt routing diagram. Move the belt tensioner pulley up and then slip the belt onto the pulley. Slowly move the tensioner pulley back into position.

Inspect the belts to ensure they are seated properly. Reconnect the negative terminal cable to the battery.


  • close Always disconnect the battery before working on any engine component. Doing so will reduce the possibility of shock and serious injury.

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About the Author

Mark Robinson is a freelance graphic designer and writer. Since 2008 he has contributed to various online publications, specializing in topics concerning automotive repair, graphic design and computer technology. Robinson holds a Bachelor of Science in graphic design from Alabama A&M University.

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