You can also contact CARid.com, give them your VIN, and they will tell you which one you need. You can usually trust them however, you can always price shop for alternators, etc. If you want the Lexus part number you can go to lexuspartsnow.com and put in your year make and model, and have the VIN handy, and you can the Lexus part number and discount price. The LPN is handy to have if you are trying to buy aftermarket.

When I had to have my p/s serviced the local Toyota dealer using Toyota parts was cheaper than either Lexus or a local using aftermarket parts. I got a 12 month 12k mile warranty on the Toyota parts installed by the Toyota dealer. The Lexus service was an order of magnitude more expensive. YMMV.

 

I recently had my car towed into the dealer because my battery light was on, and battery discharging, (suspected alternator). When the service writer called me and confirmed that, he also said that they didn’t have the alternator in stock, so I asked him if he could order a higher amperage one, as I was planning on installing a stereo that might stress a standard one. He told me that a higher amp one would or might damage the vehicle, and that the proper solution would be a second battery and cap setup. Is he right? I don’t know.

 

Perhaps, but ask yourself this question. How qualified is the service writer and how much training and background does this person have?

 

Hence the “who knows?”
I only plan on putting in less than 1000 Watts total, so I’m hoping to get by with a cap.

 

Alternators have built in regulators. You will not fry anything by putting a larger amperage alternator in. That's like saying putting a larger amperage rated battery will fry your car.

 

I'm not sure what you are trying to do. As Coleroad said alternators have regulators built into them. You will not fry anything with a higher capacity alternator. As to the second battery. I never heard of that and it is not a reasonable solution to a situation that you describe. The battery is only there to power the starter and other accessories when the car is not running. You say you will get by with a cap. Do you mean a capacitor? First, you will not be adding 1000 watts RMS. You will not come anywhere near that. If you do, you will have problems. Adding a capacitor will not solve your problem. Just get the 130 amp alternator and you will be fine.
I would be suspicious of the individual that gave you this advice.

 

Everything I’ve read agrees with you, I just relayed what he said. As far as my system goes, the 600 watt amp recommends a 75 amp alternator, don’t know about the smaller one. The reason for the cap is obvious, while the second battery would be helpful in avoiding inadvertent rundowns.

 

I just looked up the alternator that they installed (according to the paperwork) is a 27060-0p151-84, which is apparently rated 130 amp, so I should be fine.

 

okay so just came from parts store and 130 has that extra mount tab. Can I get it to fit if old one was 100amp with no third tab? If so do I need a extra bracket or something? This is so helpful. Thanks everyone!!!

UPDATE - so the 130amp fits fine. Clearly has extra third stud that was not being used so I guess I will go with that since this has Nav and heated seats and ML sound. Plus Mfr date is 7/2002. Will 30 more amps hurt my system if not correct? See my 1 min video… https://youtu.be/ca1Bw1XghCk

 

Nope, has a built-in voltage regulator that will slow/stop output if no electrons are needed.

 

that is very helpful. Thanks