How to Replace the Alternator in a Chevy Impala

by ContributorUpdated November 07, 2017

Items you will need

  • New alternator

  • Socket wrench set

  • Torque wrench

How to Replace the Alternator in a Chevy Impala. The alternator in a Chevy Impala operates various electrical devices in the vehicle while the engine is running. A voltage regulator keeps the voltage level constant and is usually part of the alternator assembly. You may need to replace the alternator if your headlights become dimmer while driving, or your battery repeatedly runs down.

Determine which alternator your Chevy Impala will need. You'll want to be sure the new alternator is compatible with your Impala's engine. The first generation of the Impala covers 1958 to 1961 and these models were available with 235 cubic inch (ci), 283 ci, 348 ci and 409 ci engines. Second generation models made from 1962 to 1964 may have a 230 ci, 283 ci, 327 ci or 409 engine.

Look at later generations of the Impala. The third generation was made from 1965 to 1970 and was offered with 250 ci, 283 ci, 307 ci, 350 ci, 396 ci, 409 ci and 427 ci engines. The fourth generation Impala covers 1971 to 1976 and was available with 350 ci, 400 ci and 454 ci engines.

Check the engine sizes for more recent versions of the Impala. The fifth generation was made from 1977 to 1985 and may be equipped with 229 ci, 231 ci, 250 ci, 267 ci, 305 ci, 350 ci or a 350 diesel engine. The sixth generation of the Impala covers 1994 to 1996 and has a 5.7 L engine.

Examine the engine size for the latest models of the Chevy Impala. The seventh generation was made from 2000 to 2005 and is available with 3.4 L and 3.8 L (supercharged and non-supercharged) engines. The latest generation debuted in 2006 and may have a 3.5 L, 3.9 L or 5.3 L engine.

Drain the coolant and disconnect both battery cables and battery tray bolts with a socket wrench so you can remove the battery and its tray. Remove the drive belt, engine cooling fan, thermostat housing and radiator hose using a socket wrench.

Take off the idler pulley bolt with a socket wrench and remove the idler pulley. Loosen the positive battery to the alternator and unplug its electrical connections.

Remove the alternator mounting bolts with a socket wrench and remove the alternator.

Install the new alternator assembly and reverse the alternator removal procedure. Tighten the positive battery terminal on the alternator to 15 ft. lbs. with a torque wrench and torque the idler pulley bolt and alternator mounting bolts to 37 foot pounds. Torque the bolts for the thermostat housing to 80 inch pounds and the battery tray bolt to 44 inch pounds.

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