Replacing alternator on an '06 4L engine.

So, my alternator was dying, my stereo killed it. It was only the 90A version that comes with the SR5 truck, my model, so I needed an upgrade. I purchased a new alternator from Bill at Marion Bumper2Bumper (a vendor on the site), and in a week, had the alternator from paid for, to in my hot little hands. Good service from Bill, good communication and quality products. I'll give the final results at the end of the install guide.

First step. Pull the battery and tray. This will give you some room to work, as the alternator has to come out from the top.

Second step, take a 14mm socket, and loosen the idler pulley. It's the pulley right in the middle of all the action on the front of the engine. They say there's a hole that you can slide a screwdriver or something in, to hold it in place with the tension off the belt, but I couldn't see it, so I just slid the belt off the alternator pulley, and let go of the tensioner.


Third step. Take the same 14mm socket, and remove the two bolts that hold the alternator to the engine block. One is easily visible at the top, the other is between the pulley beside the alternator, and the compressor for the A/C, hidden underneath. The bottom one, the coolant hose kind of gets in the way, but it is removeable, just be patient. Also, remove the 10mm bolt that holds the connection to the battery from the positive post from the alternator. And the 10mm bolt that holds the wiring harness to the casing of the alternator on the bracket on the side.


Forth step. Wrestle that bad alternator out of there. There's a hardline with a rubber hose on it, that goes from the A/C condenser into the engine bay. Bend it a little towards the fan, and move the wiring harness that was attached to the alternator. Sorry, no pics of removal, just one of the alternator on the ground.


Fifth step, installation of the new alternator. It's reverse of the removal of the old one, I recommend getting the top bolt for the alternator started by hand, then using that pivot point, to get the bottom started and installed. I tightened the bolts to 40 ft.lbs., I couldn't find a recommended torque setting online, and that seemed like a good number. If you can find another #, let me know, and I'll edit.


Next step, is only if you're replacing the belt too. I did, as mine had 104k km's on it, but the old belt was still in decent condition, with no cracks or breaks in the rubber or V-belt portions of the belt, so I'm keeping it as a backup. Take a picture of the belt. To see how it's run through the engine. As another option, Haynes manual has a decent picture in it on how to route the belt, and is another option that you can use.


Route the belt, tighten it on the tensioner, and that's it. I had my belt pop off twice after using my picture, so I used the Haynes manual drawing, and got it secured finally, for perfect running.

Put everything back on, double check your connections, and put the battery back in the truck. One more check, then start it, and see if any lights show up on the dash. No, check the belt, to make sure it's spinning all the accessories. Good? No? Go back and check the routing again.

If you're good, button everything up, and go clean up. You're done.

Now the alternator from Bill. It's a 250A alternator, that delivers 70-75% of power at idle. I have a 160A stereo in the truck, so I needed something big. After much discussion with Bill, I settled on the 250A unit. At idle, with the stereo at full crank, louder than I normally listen, I get 12.2V. At cruise speed of 14-1500rpm, I get 13.6V. With the stereo turned down, hot, I get 13.8V. Cold 14.0V. Quality product. I'm happy with it, and doing this has given me courage to tackle the alternator belt on the wifes' 4Runner. But that's another day.

 

Good write up! I will try to see if I can find the specs for the bolts. I'll be honest, I classify those bolts as a "two-grunt" torque, and haven't ever used a torque wrench on them.

 

Thanks. So 40 lb.ft. should hold them. I also wanted to mention, and forgot in the main post, the new alternator is about 3-4lbs. heavier. I assume that's the extra winding and stronger rotating parts, but I thought it was something to mention.

 

Good write up, for what it's worth, here is some info that I found in TW on torque spec's. By the way, how did you determine to find out specificallly what amperage value alternator (Generator Assembly) that you were able to get that would be able to handle the electrical amperage? Was it a specific type alternator that cost more or ?

http://www.tacomaworld.com/forum/2nd-gen-tacomas/318116-torque-spec-guide.html

 

Through discussion with Bill. I know my amps draw a max. amperage of 160A. Bill told me that the 250A alternator puts out around 70% output at idle. I would say it's closer to 65%, but that's because my idle is lower than 700. My idle is around 560rpm. So, doing the math, you get around 160A at idle. That's enough for full current draw from my amps at idle, and the engine draws from the battery. Not too bad, as idling in traffic, and the transient current draw of the amps, allows for 12.2V minimum alternator output at louder than what I usually listen to. At normal for me listening levels, I get 12.7V at idle. When cruising, the alt. puts out a full 250A at around 1700rpm, and I get 13.5V while listening at loud enough for me levels. So, the 250A alt. was perfect for me. If you're wondering which one to get from Bill, I recommend either posting in his 2nd gen. electrical upgrade thread in his vendor forum (Marion Bumper2Bumper), or PMing him. Either way, he'll discuss with you needs, wants and what to get. We decided on the 250, and now I know, it was right for my needs.

Thanks for the torque specs guide, I'll read through it, and see what I need to do to make sure the bolts don't back out. Appreciate it.
*edit* Okay, so torque specs for the alt. bolts is 43. 40lbs.ft. was my guess, so I'm pretty sure I'm good. I'll make a few trips, then check them, to make sure they're still tight.

 

Okay, got back from a real stress test on the alternator today. Here in Calgary, it's snowing, yup, I said snowing. So the accessories were all on. The heater was on full, the HID projectors were on, the wipers were going, and of course, the tunes were bumping. I had a variety of music playing, including some Lil' John, with some real deep bass. At idle, my voltage went down to 11.9V, but at 1500rpm, I was up to 13.5V. Now, because I don't have the Sport or OffRoad Tacoma, my idle is 560rpm, so the voltage drop doesn't really alarm me. It stayed steady at that voltage, and then would go up to 12.2 or 12.4V at idle. At 60kph, and 1500rpm, the voltage stayed a constant 13.5V. It's doing it's thing, no issues, and no problems. Keeping up with whatever I throw at it, and doing it well. I'm happy with the performance of it, and think that if you're wondering IF you should do this, DO IT! Bill has a quality product, and the performance is definitely there.

 

Personally I found it easiest to take it off through the Fender Well