Two items here:

1) The charge light came on last week out of the blue. I had recently repaired the rubber protector that goes around the alternator plug so I didn’t think much about it. I shut the car off, got out and looked at everything i.e. battery connections, belt, plug, etc. I disconnected the battery and then made sure the 10 mm nut for the hot wire connection was tight as well. When I was done, I tapped on the alternator with my socket wrench and said, “hey wake up, I’m in a hurry here”. Got back in, started the car and all was well. I drove it for 3 or 4 days with no issue. I headed out on a business trip Thursday stopping in Ohio for the night. When I started the car Friday morning to head to Pennsylvania, the charge light was on again. I thought, “oh great, this is all I need.” I shut the car off, popped the hood, made sure everything looked good and it came to me that I had tapped on the alternator when the charge light came on previously. I got my socket wrench out and tapped on it again. I restarted the car, all was well, and I was able to finish my five-hour drive. Soon as I got to my destination, I researched “tapping the alternator makes it work again”, sure enough I found an article that stated, “Tapping the alternator with the hammer temporarily changes spatial relationships between the brushes and what they brush against and allow a failing set of brushes to transiently make the contact they need.” Needless to say, I purchased an alternator and changed it yesterday in the hotel parking lot—it’s that easy! Only tools required were: 10mm open end wrench (to remove negative battery terminal), 12mm socket (and wrench) for 2 front idler pulley bolts and a 14mm socket to remove rear bolt. Remember I said tapping, not hitting!

2) I searched the Internet and this forum for tips on removing the alternator, but did not find anything that addresses the device that puts tension on the belt (idler pulley adjustment mechanism) and the bolt that attaches this apparatus to the alternator. My suggestion is to loosen the adjustment bolt just enough to slip the belt off, then take the other bolt completely out (both are 12mm). The adjustment bolt is the bolt that faces the radiator, the other one (on the side) holds the mechanism to the alternator. Then of course take the rear 14mm bolt out and the alternator can be removed. If you take the adjustment bolt all the way out and then the other one, the cube (see pic) will fall down into the abyss and you’ll have to fish it out!

 

Some of you might remember when you could tap on a starter to make it work again. Maybe you still can. I mentioned tapping the alternator to the guy at the auto parts store and he looked at me kinda odd and said, "I don't think that would be good."

 

Back in the day the auto part stores had retired mechanics working there and it was a lot different, those guys really knew cars.
Did you get a rebuilt Denso or a new unit?

 

I got a rebuilt unit from AutoZone, It's not what I would have liked, but I"m on the road and had few options. It does have a lifetime warranty and thankfully, on this car, it is easy to change. Hopefully it will be a good unit and I won't have to mess with it again. When I first purchased this Lexus I noticed that the alternator looked new. I believe it was a reman from O'Riellys. I researched reman Denso alternators before I left on my trip, but no one could get it to me in time.

 

Pivot bolt/nut [not shown] of the alternator and number 2 bolt are the binding bolts and they should be loosened before the tensioner bolt 1 is touched.
Similarly, before building tension hand tight bolt 2 [that allows some slide action of the alternator] and pivot bolt/nut should be in place. Not too loose to cause flopping, but instead loose enough to allow smooth movement. Spin bolt indicated as 1 to get the desired tension. Then tighten bolt 2 and the pivot bolt/nut to spec.

Salim

 

I was appreciative of the picture because the first time I removed that block and bolts I couldn't remember whether the block went in with the adjustment bolt on the top or on the bottom

 

Update

Well the remanufactured alternator from AutoZone conked out on the second day of our vacation trip to Florida. The charge light came on sitting at a stoplight after six hours of continuous driving. It was just over 6 months old. Thankfully I was only 7 miles from one of their locations and changed it out in the parking lot without any issues. It has a lifetime warranty, so it didn’t cost anything but my time. So glad it is easy to get at, although there is limited room to work. I knew the risk of buying a reman, but as I posted earlier, when it went out before I was out of town on a job and had limited resources to even get one.

The alternator that was on the car when I got it was from O’Rielly’s (and the battery as well). Both looked brand new and the alternator had a remanufactured sticker on it and the battery was a “Super Start”, which is O’Reilly’s brand.

Point being, buy new, have it rebuilt, or purchase an OEM unit from a salvage yard (that has been tested).

 

Thanks for the update and glad things worked out for you with very little discomfort.

With first gen getting up in years, 24 or less, I would still pick salvage yard product over reman, but I would service it ... new bearings, brushes, diode pack and regulator. Usually this requires being at home.

Incidentally, I always prefer renting instead of taking my vehicles on long road journeys. I have not priced the rentals, but it the peace of mind and convenience + wear-tear.

Salim

 

In the past we have rented cars for long journeys, but the price has doubled in the last two years. They want $500 a week for a midsize SUV, and that's with our corporate discount. Also, hassling with Enterprise has been an adventure in and of itself. They never have the vehicle we want (unless I pick one up at the airport, which is 42 miles from our house) and several have just plain been a mess i.e. chemical smells from covering up smoke and who knows what else, filthy windshields, half washed, etc. One was wrecked in the front and I had to take pix and get verification that I would not be held liable for it when I returned the vehicle. They tether both keys/fobs together with a cable so I have another bundle of responsibilities to deal with (they inform you that each key costs $250 if lost). One time the vehicle was missing the key/fobs and all I got was a valet key, which meant I had to manually open the doors and trunk, which is fun when you load and unload a much as we do. Another time an employee called and said they were going to have to move my vehicle because the business next door (where Enterprise instructed me to park) was going to have it towed. When I asked how they were going to move it when I had the keys and was 1000 miles away, the manager said her husband owned a wrecker service and could move it. That was it for me. I realize there are other rental car companies, but to be honest I'm just tired of dealing with rentals and we've been talking about getting off the road anyway.

 

I found Denso's website for all their products, though remanufactured, they do have alternators for the RX300. They can also ship them to a local NAPA store for pickup.
https://densoautoparts.com/

 

Thank you for posting your experience on chain auto part store "reman" alternators.
I see nothing has changed in last 30 years as they still suck. lol