This 2008 Buick Enclave CXL came in with the complaint that the battery would go dead while driving. The battery light was on and there was a message on the dash to service the charging system. Something else that I noticed but cannot duplicate here is that there was a steady moan from the engine area. This article is more about how to replace the alternator and less about diagnosis. The battery should be disconnected. It is located under the floor board behind the passenger front seat.
The first step in removing the old alternator is to remove the oil filler cap.
Doing so allows the top engine cover panel to be removed.
After the oil filler cap is removed the cover will lift straight up and off of the engine. Notice the two silver studs with ball tops at the rear of the engine. These match up to sockets in the cover.
The coolant overflow tank is the next part to be removed. There is a hose attached to the tank that is easier to remove before the tank is unbolted.
Now the two 10 mm headed bolts that hold the tank in place are removed.
One more bolt holding the a/c high pressure line in place. The a/c line and a power steering hose will need to be moved around slightly while working the alternator around the engine compartment.
The tank can be positioned out of the way in several different directions depending on the area of access needed at the time.
Following the a/c liquid line around to the front of the engine you will find a 10 mm nut holding the clamp down.
The belt tensioner assembly is accessed from under the vehicle. I used a 1/2″ drive breaker bar to move the tensioner and then removed the belt from the alternator.
While in the same area the bolt that holds the back idler pulley in place also needs to be removed. That bolt doubles as an attaching bolt for the alternator.
It can be accessed from the bottom or the top of the vehicle. The bolt has a 15 mm hex head.
This is a better view of the pulley, bolt and alternator as they are assembled in the vehicle.
The bolt and pulley will need to be moved to the most forward position possible in order to remove the alternator.
After the alternator is free enough for it to rotate up, the pulley and bolt should be removed. This will make moving the alternator around much easier. It is a must to remember to reinstall the pulley and bolt back into the alternator housing before securing the alternator to the engine. This pulley and bolt cannot be removed from the alternator while it is still bolted in place and by the same token it cannot be installed if the alternator is already secured to the engine.
Moving to the mounting studs and nuts that hold the bulk of the alternator to the engine. The GM service information states to remove the bolts but this vehicle uses studs instead. So after removing the two 15 mm nuts and the hose bracket from the studs, the studs themselves will need to be removed.
A 7 mm socket is needed. There are quite a few threads so it takes a lot of turning to remove the studs.
This is how it looks in the engine compartment. I will tell you that it is easier removing the studs than it was to re install them. I had to use my left hand under the front of the alternator to support it while I re installed the studs with my right hand. You may notice the alternator output stud slightly right of center in the next picture. The attaching nut has a 13 mm hex. I had already removed it and moved the cable out of the way earlier. Same goes for unplugging the alternator harness connector.
Now the trick for easy removal out of the engine compartment. Under the vehicle at the front the of the wheel well there is a phillips headed screw that needs to be removed.
There are several more along the front half of the inner fender. It is easier to work with the wheels turned to the right.
There are several push pin style plastic retainers that also need to be removed. After all of the fasteners are removed the front portion of the wheel liner will pull down and out of the wheel well.
The alternator can then be maneuvered out through the passenger wheel well opening. It may seem like a pain to take the alternator out this way but it is far easier than doing it by the factory manual. It states to drain the coolant, remove the upper radiator hose, remove the front engine mount and then the engine mount bracket before unbolting the alternator.
Hope this helps.