If the alternator on your F-150 is showing signs of failing, then it may need replacing. Replacing the alternator on a Ford F-150 is a fairly straightforward job, and doesn’t require any special tools or expertise.
This procedure details the removal of the alternator from the 3.5L turbocharged engines, but it’s similar for other engines across the F150 range.
1. Disconnect the negative battery clamp
The battery is located under the hood on the left of the engine bay. Using a socket wrench, loosen the 10mm nut securing the negative terminal clamp to the battery. The negative terminal is the black one to the front of the battery. Once removed, move the connector away from the battery so it cannot accidentally touch the terminal.
2. Remove the air intake Y pipe
Start by loosening the two clamps that hold the ducting in place. You’ll need a small socket wrench or flat blade screwdriver. Next, remove the coolant hose from behind the left side of the pipe by pulling it out. Then remove the air intake sensor connector from behind the right side of the pipe.
Now loosen the lower hose clamp that connects to the turbo intake pipe. You should now be able to remove the air intake Y duct from the engine. You may need to wiggle it about a bit to free it from the engine.
3. Remove the turbo intake pipe
From inside the drivers side wheel fender, open the clamp holding the turbo intake tube in place. This can be tricky to access, you’ll need an extension bar on your 7mm socket wrench to give better access. Once loosened, you should be able to pry off the turbo intake ducting from the turbo.
4. Remove the Auxiliary belt
You should now have access to the front of the alternator and the drive belt. If you can, take a photo of the drive belt path using a smartphone, to help when reinstalling.
Now, using a long breaker bar with a 15mm socket attached, rotate the drive belt tensioner to release the tension on the belt. When the tension has been removed from the belt, pull the belt away from the tensioner and slowly release the tensioner back into place. Now remove the belt from the engine.
5. Remove turbocharger bypass tube
The turbocharger bypass tube runs along the front of the alternator and needs to be moved to one side to gain access to the alternator. Rotate and squeeze the sides of the connector that attaches the tube to the turbo intake pipe. It should pull off easily and you can then push it to one side.
6. Remove the electrical connectors from the alternator
Start by removing the electrical connector from the front of the alternator by squeezing it. Then remove the positive connection from behind the rubber covering by loosening the nut that is holding it in place. Put the nut in a safe place when removed as you may need it when fitting the new alternator.
7. Remove The Alternator Mounting Nuts
There are two fasteners holding the alternator in place. The top one is a nut and the bottom one (located to the bottom left) is a bolt. Remove both completely to release the alternator.
8. Remove The Alternator From The Engine Bay
The alternator can now be removed from the engine. You’ll need a long flat screwdriver or something similar to free it from the lower mounting bracket. It can be quite difficult to do this by hand and you may need to tap the alternator gently with a rubber mallet or the end of a piece of wood. (tap the bottom left side of the alternator to free it). Once free from the lower mounting bracket, pull the alternator towards you and remove it through the top of the engine.
Fitting of the replacement alternator is the reverse of the above steps. Take care not to over-tighten any of the bolts. Use a torque wrench to tighten the mounting bolts to 35 Ft-lbs or 47 NM.