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Discussion Starter · #1 ·
2012 Highlander AWD V6 Base
144K miles.

I started to smell a faint smoke at a drive thru and saw light grey smoke come out from the side of the hood on the passenger side. Luckily, I got home okay but not sure what would cause such smoke? All I can see if looking straight at the alternator is where the smoke 'maybe' coming from. It's very faint but something is definitely cooking.

One thing I also noticed is that my battery voltage on the digital display has been showing 12.1V and dropped to 11.8V at the drive thru. I know the battery likely needs to be replaced soon but could this be the alternator going?

No liquid spilled, nothing rubbing, or anything else at least from what I can see from the top and sides.



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Discussion Starter · #2 · (Edited)
So I ended up replacing the alternator. I watched a number of videos and definitely helped in terms of not having to take apart more than I should. This seems very similar to many years from 06+ Highlander and 14-16 as well from what I understand.

Tools you'll need:

New alternator (I bought a 130A rebuilt alternator from Advanced Auto Parts which is 'supposedly' halfway decent compared to others but we'll see.....)

A wrench with:
10mm socket
12mm socket
14mm socket
An extension (6" or 10")
14mm crescent wrench
Floor jack & take off the passenger side wheel (you'll thank yourself later...)
Big vise grips to remove the clamps from the radiator hoses
A big jug of coolant
Optional but helpful: Funnel to release any air bubbles once everything is complete

Before you do anything = Disconnect the battery cable from the positive terminal

  • A number of wires that you'll need to disconnect that's in front of the radiator
  • Remove the radiator fan: There are bolts along the top (four 10mm I think) to move the radiator fans which can be tilted up to the right side; a must in order to wiggle the alternator out & install the new one. You may need to remove some brackets along the top including undoing the radiator hose; try not to spill it all over the O2 sensors nearby.
  • Take off the big radiator hose left of the radiator hose; you do NOT need to take off the metal pipe on the side next to the radiator like a lot of videos on YouTube show.
  • Lift the vehicle and take off the passenger side wheel and access the two 10mm bolts where it exposes the serpentine belt.
  • Optional: Replacing the serpentine belt: There's a tiny hole on the belt tensioner where you'll take a 14mm bolt and lock it in place with a small bolt. Slip the belt out, easy access also for the lower 14mm to undo the bolt.
  • The top 14mm bolt is the easiest
  • The bottom 14mm bolt can be accessed from the bottom where you just took off the panel looking at the belt
  • The tricky part is the 12mm bolt holding the alternator located just above the AC condenser I believe. The old picture below should help you. I used an extension to get to the back. Swap the bracket to the new alternator. I had the bolt taped with electrical tape so I can get it in without dropping it, and pull it off once it started to thread in. Don't tighten this all the way until the two 14mm bolts are tightened as the bottom can be tricky otherwise to re-tighten I found out.
  • Make sure all connectors and the ground is connected and the radiator fan secured in its place
  • Once everything is swapped, make sure to refill the coolant and allow bubbles to escape; I used Lisle's spill-free funnel to pour more in, and once everything was done, I turned the engine on and let it run for 10-15 minutes until the bubble stopped.

It does take about three hours if you've never done this before.

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The dreaded 12mm but with an extension, you'll be able to take it off. It's not as bad as I thought. I didn't want to try to guess the position of the bolt as it's very difficult to see from the top so once I moved the bracket to the new alternator, I took the bolt and taped the head using electrical tape so it will stay in place. I would tighten this 90% before tightening the two main 14mm bolts (short on the bottom, the long one on top) then tighten this 12mm all the way.

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Loosening the serpentine belt tensioner: 14mm bolt but you'll want a long handle or take a 14mm and use a 16mm crescent wrench as leverage. Turn counter-clockwise and insert a bolt highlighted at the bottom where you'll be able to lock it behind the small space as it moves to the right; the bolt will stay there with it loose enough the belt can be slipped off & installed. Just make sure to pay attention to how the belt goes back in. Once the new belt is installed, take the 14mm and pull the bolt out. There's nothing to tighten or align here.

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2008 Highlander Limited, 3.5, JBL
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I do it without pulling the tire. The bear for me was the bottom alternator bolt, which I had to get creative on leveraging wrenches in order to break it free. Once it was broken free though, the rest of the job is not bad, if you have done it before. The first time took 4 hours. The second took an hour.
BTW, Toyota specs are 13.2V minimum from the alternator.

Chris
 

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Discussion Starter · #5 ·
whats your voltage now while driving?
14.1V though I have a feeling the battery is next. I was reading 13.7V on my way home today. Before the alternator went, it was reading close to 12.1V 😬

I do it without pulling the tire. The bear for me was the bottom alternator bolt, which I had to get creative on leveraging wrenches in order to break it free. Once it was broken free though, the rest of the job is not bad, if you have done it before. The first time took 4 hours. The second took an hour.
BTW, Toyota specs are 13.2V minimum from the alternator.

Chris
Ya pulling off the tire made it a breeze get from underneath. Though if there's one tool I wish I had was a longer ratchet wrench for more leverage. Recently bought an electric floor jack which I was quite surprised...no more carrying the 2-ton floor jack across the yard.
 

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14.1V though I have a feeling the battery is next. I was reading 13.7V on my way home today. Before the alternator went, it was reading close to 12.1V 😬
Battery may be fine at that voltage, my alternator (both original and replacement alt when mine did something similar) never output more than 13.7ish on my old 08. ECM/ECU held it pretty low, never getting into the 14's.

I wills say though, when my alternator went, it took the battery with it, but the voltage was a lot lower than 12.1V. I lost like half the diodes, running voltage was like 11V. Just enough to keep the car running, but if you turned on too much load, let just say it didn't end well.
 
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