DIY: 987.2 Alternator Replacement

I’ve been having issues with my alternator ’s voltage regulator with the following symptoms The engine idled a little rough (especially on the first minute after startup while idling above 1k rpm) The lights would dim/flicker with the rough idling The car was a little slow to start. This was a very minor annoyance and I thought it would go away after changing the spark plugs; but learned after this job that you should be investigating the battery, alternator, and starter for this. The new (remanufactured) alternator has fixed these issues. Note: this guide only applies to the 987.2 . The .1 Cayman/Boxster uses a different serpentine belt, pulleys, and possibly a differently alternator part. It’s a similar process, but has it’s own challenges. Here’s a video for 987.1 alternator removal . From my research, Porsche calls for dropping the engine to do this, but I didn’t find it necessary. It may make it a little easier if you have the ability to, but I did this replacement without that. Links: 987.2 Alternator Replacement video (keep in mind, this video has some inconsistencies with my experience) Tools/Supplies Needed: Plastic trim removal tool T30 Torx bit E12 Torx socket (The video calls for an E10 Torx socket, 987.1’s seem to use an E14; maybe it differs by year) 10mm and 12 or 13mm hex sockets[1] 30mm wrench[2] Metal pry bar or flathead screwdriver that you can use as a lever, see video/step 9 New/remanufactured alternator (Bosch part #: AL0898N/AL0898X) New or remanufactured alternators can be found at Rock Auto, FCPEuro, and Pelican parts. I’m sure your local Porsche dealer would be happy to sell you one for 2x the price Bosch will. For what it’s worth, I bought a remanufactured alternator (AL0898X) and it looked brand new. Optional: PB Blaster penetrating oil or other lubricant to free up the alternator’s bolts[3] Sandpaper[4], see steps 10 and 11 Steps: Remove the upper and front engine padded covers [plastic trim removal tool] , upper engine metal cover [T30 Torx bit] , and the front engine metal cover [10mm hex socket] . Open the frunk and disconnect the battery cables [10mm hex socket]. Make sure to do this before disconnecting the alternator’s wires. Take note of the accessory belt routing and how it runs over the alternator’s pulley. Locate the belt tensioner- a metal hex post inside the belt below the alternator. Turn the belt tensioner clockwise to release the belt tension [30mm hex socket] and remove the belt from the alternator. Spray the 2 nuts at the bottom of the alternator with PB Blaster/penetrating lubricant before removing them [E12 Torx socket] . Disconnect the wire plugged into the back of the alternator. Press down on the clip locking the wire into the alternator and gently pull it away. Make sure to also remove the wiring clip that is pushed into the back of the alternator. If your alternator has a black plastic cover on the thicker cable on the back, remove the cover. Loosen the nut [13mm hex socket] securing the cable and remove it by hand to avoid dropping it. Remove the cable from the alternator. Gently work the alternator upward to free it from the engine block. You may need to use a metal pry tool or flat head screwdriver to separate the alternator up from the engine. With the alternator loose and disconnected in the engine bay, note the black rubber hose at the front upper edge of it. This hose will get caught on the alternator and will need to be moved up and out of the way as you work it out. First, lift the alternator off the engine block’s bolt holes. You may need a lever (like a flathead screwdriver) to help lift the alternator from the engine block, especially the left side, which often seems stuck. Lift the alternator up and move it forward. Try to get the back of the alternator up and over the bolt holes, then work the alternator down and out. The pulley should face down and slightly towards the center of the car. At a certain point, a bump at the top of the black plastic on the back of the alternator gets stuck on the hose that sits above the alternator. Move the hose up and over the bump to help free the alternator. Then continue working it out and down. As you pull the alternator out, be careful of the power steering pulley to the right of it- the old plastic can be brittle and easy to break off the outer lip of the pulley. Take note throughout the process to reverse it and put the new alternator in. Take this chance to clean the alternator cable and the grounding points (where the bolts go) for the alternator with sand paper or a metal brush to clear any rust or corrosion. Gently work the new alternator into position in the engine bay. Start the with the alternator pulley facing slightly downward and work the alternator onto the engine block reversing the process to work the alternator out. Again, be careful of the power steering pulley. If you get the alternator into position, but it won’t go down onto the bolt holes, the alternator’s brackets may be too tight a fit around the bolt holes.[4] Once roughly in position, reconnect the cable and reinstall the nut [13mm hex socket] . Finish putting the new alternator in place. Put the alternator bolts in place. Replace the cable’s plastic cover, the wire, and the wiring clip onto the new alternator. (This was quite annoying- it takes some fiddling and a helping pair of small hands.) With the new alternator in place, screw in the bolts [E12 Torx socket] . Torque to 45 Nm/ 33 ft-lb . Turn the belt tensioner clockwise [30mm hex socket] and reposition the belt on the new alternator. Make sure the grooves of the belt are positioned correctly on the alternator pulley and nearby pulleys. Also check the bottommost pulley as the belt may have come loose or out of position there. Reconnect the battery cables [10mm hex socket] . Check the belt once again and make sure it’s positioned correctly on all the pulleys. Start the car and let it run for a minute. Monitor the belt, alternator, and electronics to make sure everything is working correctly. You may receive some errors because of the disconnected battery, but these should go away after a minute of driving. If everything looks good, replace the front and top engine metal and padded covers [10mm hex socket and T30 Torx bit] . Notes: [1] On my car, the old alternator used a 13mm nut on the cable, but the new one used a 12mm nut. So it may differ for your alternator. [2] A 30mm hex socket likely will not work because the belt tensioner is positioned close to the bottom of the engine access panel. [3] I sprayed the bolts with PB Blaster but didn't need to, mine weren't stuck at all. [4] The brackets of the new alternator were slightly too tight to fit around the holes for the alternator bolts that are built into the engine block. I struggled with getting the alternator down onto the bolt holes for a while and finally I ended up sanding/light dremel-ing the insides of the brackets a little to create a millimeter or two of clearance for the alternator’s brackets to slide down onto the bolt holes. This job is not difficult but it is a bit tedious . Getting the alternator out is definitely the most time consuming part. Unfortunately, I didn’t record getting mine out and the video I linked does not do a great job of showing how to best do this. I tried to explain how I did it. Keep an eye on the black rubber hose above the alternator and be careful moving it up out of the way, because this is a fuel line. Getting the new alternator in, was not as difficult; but I struggled with getting it down onto the engine block’s bolt holes. I finally realized the bearings in the alternator’s rear brackets stuck out a little too much towards the alternator’s body and didn’t allow enough clearance for the alternator to sit properly on the engine block. Once I sanded them down a little, the alternator fit right in. I could maybe do this job in an hour and a half now; but it ended up taking about 3 hours figuring everything out.

Great write up. Hope I never need to replace mine, but your detailed coverage is a big help. I typically scan and save as a PDF, documented work descriptions like this one for future reference. In step #7, you mention removing the 13mm nut by hand to avoid dropping it. I’ll share my hack for those hard to reach circumstances. I bought a pack of those neodymium magnets, the super strong rare earth ones, and I slap one on the socket or extension I’m using to hold the nut or bolt or whatever in place. I also slap one or two on the shaft of any screwdriver I’m using when extracting a screw from a long reach into a confined space. The so-called magnetic tipped screwdrivers are far too weak to really hold a screw securely. I keep them in my tool kit and find myself using them frequently for lots of projects.

An excellent writeup. The linked video is interesting - several things were shown that should have been "don't do this" ( WD40 does not loosen rusted nuts, nor does it penetrate behind a bolt head to lubricate the junction..) But - it did show it's possible to get the thing out of the engine compartment without dropping the engine. I suspect from the alternator electrical noise I get - that mine may be nearing the time when it needs replacing. I won't be doing the job (I seem to have aged out of most DIY..) but this thread and that video will be good references for my mechanic (who I'm sure - since part of his job is caring for race 987s - probably has worked this out himself.)

Yes, the video was not the best guide. Good to know about the WD-40 - I removed any mention of it from my write up. I’m sure your mechanic will have this job done in 1 hr max haha.

Regarding “ figuring everything out”. The subsequent trips are always smoother by experience, that’s even true of the combinations of tools you use. The Spyder has a unique shelf void of pockets or speakers. Its disassembly is specific when it’s time for an AOS . Another example is coils and plugs, I mark the covers with painter’s tape, front, rear, top and bottom.