Replacing Your Alternator


From a post on renntech

Replacing the Alternator on a Boxster is easy for anyone who has a basic toolset and about 2 - 3 hours to spare.

Take a few minutes to read the following note before you purchase a new Alternator. A new alternator can cost you anywhere between $500 to $1,300, but a 10 minute check can save you hundreds. Here's how:

Alternators have 4 major components:
* Alternator core (the wire winding and the entire Alternator body)
* Bearing (what the shaft and the pulley rotate on)
* Voltage Regulator (rectangular component on the back side)
* Rectifier (Horse shoe shaped component on the back)

If you know that the Alternator is bad and has to be replaced, first proceed with the following tests:

* Check to see if the inner wire winding look OK (clean) and does not smell burnt (if this case your alternator core is OK)
* Check to see if the pulley (what the belt sits on) rotates smoothly and freely. (if OK it would mean your bearing is sound).

If your core and the bearing are both OK, chances are that either the voltage regulator OR the Rectifier has gone bad. These will cost you anywhere between $20 to $80.

On a bad Alternator chances of a faulty Voltage Regulator are rather high, but to be sure you can simply unscrew the regulator OR take the Alternator to any auto electrical shop - they can tell you if the regulator is shot. In this case you can simply replace the regulator on the old Alternator.

Here is the simplified version of the Alternator OR Alternator component change procedure: 

* Access the engine bay on the Boxster

* Disconnect the battery. (You may have to re-enter your radio code after you have reconnected things, depend on your model year)
* Remove Passenger seat
* Remove carpet panel and the front panel cover (see pic)
* Relieve the pressure at the tensioning pulley and remove the Belt
* Unbolt and remove the Alternator by unbolting the right hand fastening screws, loosen the left hand fastening screw by three turns, tap the fastening screw to losen the threaded bushing in the generator arm., lift generator up and out of the slotted alternator bracket, unscrew the fastening screw and remove the deflection roller, turn the generator clockside so the swivel arm is near the crankcase and the holding arm projects beyond the fastening eye, pull the alternator foreward a little and undo the electrical connections.

* Replace components (Regulator OR Rectifier) or New Alternator

* Follow: Put in first what came out last.

Reconnect the battery.

And if you have to replace the entire Alternator because the mechanical parts are bad (bearings or windings), you can go to NAPA or any number of other sources, you don't have to be the captive of the dealer and buy the Porsche branded part. There is nothing special about a Boxster alternator that any auto electrics shop can't handle for you.