6.1 Alternator Replacement

I recently noticed a whining sound coming from my engine. Definitely tied to engine RPM, so the logical suspects were anything connected to the serpentine belt, so water pump, power steering pump, alternator, A/C compressor, and maybe, if I was lucky, an idler pulley, since those would probably be the cheapest of all those possible culprits to replace. Here's a short video of the sound. It's only 7 seconds, but it was still too big to upload to this forum, so I had to put it on YouTube:



I tried spraying some silicone spray into the idler pulleys, but that had no effect. The A/C compressor makes a certain sound of it's own, but that went away when I turned the A/C off, so pretty sure that wasn't the culprit, either. Water pumps usually leak when they go bad, and a power steering pump problem quite often makes more noise when the steering wheel is turned, so that leaves the alternator. A quick voltage check with the car running showed 12.32 volts, which is too low. It should be in the 14.0 to 14.5 volt range, so... looks like I gotta spring for a new alternator.
Yikes, they're not cheap! Local parts stores had remanufactured ones starting at $300 and they went up from there. A new one could be $500 or more and if you want an OEM Mopar replacement, well, I already have a second mortgage. Enter RockAuto which seems to be pretty hard to beat on price. They have a range of ones to choose from, and while I wouldn't go for the cheapest one listed, I did pick a middle of the range remanufactured Bosch unit, for about $200.

Now, the how-to part:
First thing first! Disconnect the battery! The main wire going to the alternator is pretty much a direct connection to the positive battery terminal, so if you don't disconnect the battery, sparks WILL fly! You really just need to undo the negative (-) connection, that's good enough.
Also, you'll have to get under the car to do this job, so jack up the passenger side behind the front wheel, prop with a jack stand, and pull off the bottom tray. It's the same tray you remove to change the oil, so no biggie there, 4 little bolts and it's free. I also removed the tray in front of that, the one just behind the air dam, but looking back I'm not sure that was necessary.

Back to the top. Remove the intake duct. There's two screws on hose-clamp-like things that have to be loosened, and the electrical connection to the air flow sensor has to be disconnected. Slide the red lock clip back, and then you can squeeze the connector and remove it.



With the duct removed, you can now get your hands down in there to loosen the tension on the serpentine belt and remove it. I used a 3/8" breaker bar. There's a square hole in the tensioner pulley arm that the breaker bar fits into, then you just pull up to release the tension.


The alternator is held in with 3 bolts, 2 on the bottom, one on the top. Get the bottom ones first. I was surprised how tight mine were, so a long breaker bar may be required. Here's where they are:



Back on top, remove the last bolt. The alternator should now be free. Ordinarily, I would undo the electrical connections first, before unbolting the whole alternator, but on this one you can't get at the connectors until you free the alternator. Here's the top bolt:



Once free, undo the connections. The control wires are on a tricky little plug. You gotta slide that red piece back before it will come apart. It's kinda like the one on the MAF sensor, it's a lock to keep it from coming undone on its own. Once back, you can then squeeze the connector tab and it will come apart. Here's a shot:



The main wire has a grey plastic guard over it, just squeeze and it comes off pretty easy. One nut holds that connection. Note the alignment tab, you'll want to put it back on the new alternator in the exact same position, so that everything lines up properly.





Now, the alternator should be totally free. And now comes the hard part. Getting that sucker out of there. I think by rights you should take out the upper radiator hose to make room but I didn't. I don't like taking things apart that don't have to be, and I especially don't like it if there's a chance those things might leak after being reassembled. So I fought like crazy and finally was able to get the old one out. Putting the new one it was a little easier, gravity helps that operation. I should also mention that I removed the "6.1 HEMI" plastic engine cover on that side, and slid the wire harness clips off the bolts that stick up off the right side engine head, so that I could get the wiring harness out of the way.

With the new alternator in its space, put everything back in reverse order. Hook up the main wire, then the grey cover, then the control wire, put the alternator where it goes, 3 bolts, tighten 'em up. Make sure you slip the wiring harness clips back over their studs.



Re-thread the serpentine belt through all the pulleys. You remembered how it goes, right? Of course you did. Easy-peasy. Almost done. Put the air duct back on. Re-connect the MAF sensor. Make sure you put the sensor in the correct orientation, same as it was when you took it apart. Here's a picture if you forgot:



Start it up! Whoa! No more whining noise! Whew. Glad this wasn't for nothing. Quick check with the volt meter. I'd say that looks like a happy alternator.



Oh - almost forgot! There's a core refund for returning the old alternator. Save the boxes the new one came in, they want the old one returned in the manufacturer's original box. I saved the shipping box, too, and used it over. RockAuto web site will let you print a shipping label. You have to pay for it, but it was cheap, like 7 bucks. Core return is $75, so well worth a trip to FedEx! Wait, that means the new unit was really only about $125 - hmmm, not too shabby.

So, if you're willing to get your hands dirty and don't mind losing a minor amount of skin, hope this helps you save some of your hard earned cerveza money! Vaya con Dios, muchachos!

 

Good pics &info!!

 

Thanks, guys. My car has a little over 72K on it. Yeah, I thought that’s a little soon to have an alternator go bad, but it is like 14 years old, so I guess I can’t complain. And the car has been pretty trouble free knock-on-wood.

There’s one thing I forgot to mention about diagnosing the problem. I started the engine to measure the charging voltage, and that was a totally cold engine. It ran for less than a minute, and after shutting it off, the alternator was too hot to touch. You expect things like exhaust headers to heat up quick, but not the alternator. So that was another clue as to what was failing.

 

Very nice write-up. Thank you.

 

You seem handy enough to consider a bearing and brush replacement the next time.

 

I’ve done that in the past, for a BMW alternator, (those are REALLY expensive ) but I didn’t see where that was available for this one. Maybe I shoulda dug a little deeper on the internets.

 

I'll keep that in mind when one of mine on the BMW's (have 2) goes. I buy lots from Rockauto (even big savings for us in Canada) and haven't been disappointed.