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How to Replace the Alternator in a Nissan Sentra

by Contributor

The Nissan Sentra uses an alternator to run electrical devices in your vehicle while the engine is running. A voltage regulator maintains a constant voltage level and is frequently integrated into the alternator assembly. If your battery continually runs down or your headlights become dimmer while the engine is running, you may need to replace the alternator.

Step 1

Determine which alternator your Nissan Sentra will need. You'll want to be sure the new alternator is compatible with your Sentra's engine. Models made from 1982 to 1986 may have a 1.5 L, 1.6 L or 1.7 L diesel engine and models built from 1986 to 1990 use 1.6 L engines. Models made from 1991 to 1994 may have a 1.4 L, 1.6 L or 2.0 L engine.

Step 2

Look at later versions of the Nissan Sentra. 1995 to 1999 models may have a 1.6 L or 2.0 L engine and engine sizes for 2000 to 2006 models are 1.8 L, 2.5 L and 2.0 L. The current generation debuted in 2007 and is available with a 2.0 L MR20DE engine.

Step 3

Disconnect the negative battery cable with a socket wrench. Take off the engine cover and engine under cover if you have a 2.5 L engine. Remove both lead wires and the electrical connectors from the alternator.

Step 4

Loosen the adjusting bolt for the drive belt with a socket wrench so you can remove the accessory drive belt. Remove the retaining bolts on the alternator with a socket wrench and take the alternator off the vehicle.

Step 5

Install the new alternator assembly and put the retaining bolts on loosely. Replace the drive belt and adjust the tension with the adjusting bolt. Connect the two lead wires and the electrical connector for the alternator. If you have a 2.5 L engine, use a torque wrench to tighten the upper retaining bolt to 18 to 23 foot pounds and the lower retaining bolt to 33 to 38 foot pounds. Otherwise, torque the retaining bolts to 25 foot pounds.

Install the engine cover and engine under cover if you have a 2.5 L engine. Reconnect the negative battery cable with a socket wrench.

Items you will need

  • New alternator
  • Socket wrench set
  • Torque wrench

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