Tom57

With the shipping cost for a heavy alternator, even if Denso accepted alternator cores, you wouldn't net much, if any, $$. Suggest calling a few local auto parts stores and ask if they pay for cores only, without a purchase.

BMW7_LS430

Thanks for the original post chunkyda
I followed instructions to the tee and worked slowly but still was able to finish the job under 2 hours.
I went for Duralast rebuilt alternator from Autozone because I wanted it on the same day (plus the lifetime warranty which is easier to avail locally). Car is back on the road. I feel lucky that it had died in the garage rather than someone on the road.

I still haven't returned the core and thinking of rebuilding it myself as a spare. Are there any rebuild kits for OEM unit? How to find out what is wrong and needs to be replaced?

Bocatrip

Just out of curiosity. Have you checked the voltage output of the new alternator compared to the one you replaced?

BMW7_LS430

Before replacement idle voltage started with 13.9 and then kept dropping to 13.4 and was 13.3 to 13.6 even when car was on road.

Now starting voltage starts at 14.3 and idle is still dropping to 13.4 to 13.6 but when car is running on the road it is between 14.0 and 14.3

Bocatrip

I have to apologize but I have not read this entire thread. I have an original alternator from 2001. Your readings from your new alternator are identical to mine other than what the output is on the road as I am not able to check. How are you able to get your readings when driving on the highway?

Tom57

On the '04 - '06 models, you can get voltage output on the screen while driving. Not the same with '01.

Tom57

Boca, suggest you check out the alternator output soon. Mileage isn't the only factor affecting alternators. This was my experience on my '01: https://www.clublexus.com/forums/ls-...001-ls430.html

Bocatrip

Thanks guys for your feedback. I've taken the alternator readiings years ago and they are consistent to today's reading however I am unable to check reading while on the highway unless reving the engine up for extended periods, but I assume they are the same as when the car warms up (in the 13.6 range). Considering I have never gotten stuck in my 5 years of ownership and am now on my 2nd battery,(close to 3 years per battery) I'lm fairly confident that the alternator is putting out enough to keep me going up this point. I've read of a post where the owner replaced his alternator with a Denso only to find the reading to be the same. His readings were the same as mine but he was concerned and decided to change the alternator as a preventative measure. I don't believe I'm getting the 14.2 output on the highway, but 13.6 is most likely enough to keep the battery at a decent charge capactity. Yes, I know that for maximum battery life we ideally want to keep our batteries charged as close to 100% as possible. When I do put a CTEK charger on my battery when leaving for an extended period without driving, it usually shows a full charge in a very short period of time.

Lavrishevo

iTrader: (1)

Your alternator is fine. When it gets into the 12's is when you approaching the end of the voltage regulator. Even my new Denso with new battery only hits 14+ volts on a cold start for very short period of time.

BMW7_LS430

I took readings again today and the alternators mostly stayed in 14.1 to 14.3 range. It never dropped below 13.9.

The previous readings were right after alternator change and they may be lower because battery must not be fully charges after alternator failure.

Lavrishevo

iTrader: (1)

The problem is measuring voltage is not the proper way to test an alternator. Voltage varies based on the load. Measuring amperage is what truly tells you if you have an issue. This is why electrical shops remove the alternator from a vehicle to test it properly. I'm sure RKW could elaborate on this as well.

Tom57

It's a pretty simple equation: volts x amps = watts. Volts is the force or pressure of the electrical current. Amps is the amount of electricity flowing. The LS OEM alternator is rated at 130 amps. The voltage varies depending upon the wattage demands (current draw) of the accessories, engine running and battery needs.

As an alternator ages, the maximum voltage output slowly declines. A reduced voltage output results in reduced wattage output. (Ex. A 1 volt drop in alternator output = 130 less wattage output.) A healthy alternator should be able to increase voltage as the wattage demands of the engine, accessories and battery call for it. Increased wattage demands are the highest just after the engine is started since the battery is drawn down by the starter motor. Since wattage demands vary, voltage will vary, so measuring voltage output under various conditions (to meet the wattage demands) is a measure of the health of the alternator. So, as the wattage demands of the vehicle increase, so should the alternator voltage output. This is why alternators are tested "under load" to determine if the voltage output will increase to meet the increased demands placed on the alternator. This also explains why alternator voltage output fluctuates, as the wattage demands vary.

A healthy battery should put out between 12.5 - 12.8 volts standing alone. A healthy alternator should deliver 13.8 volts or more. This doesn't mean your car won't start if the alternator output is below 13.7; it means the battery is not being charged sufficiently. Battery voltage output slowly drops over time; alternators voltage output slowly drops over usage (internal wear and heat).

See also: https://www.clublexus.com/forums/ls-...or-output.html

Bocatrip

Tom57, I've read your other threads with regards to changing your 01 LS430 alternator. Thank you for your very thorough info. At one time I was able to find a replacement alternator for my 01 LS430 on RockAuto. No more. As you mentioned most sites will not show Denso part number 210-0508 as compatible with the 01 but only 02-04. Can you recommend a retailer to purchase an authentic Denso rebuild for the 2001 with part number 210-0508? I would go to Lexus but don't want to pay the premium for their prices. Also, were you able to find a valid reason that even at the Denso site they show this part number not being compatible with the 01. Why??? Are the fittings for the rear plug the same? Thanks very much.

Tom57

Bocatrip, Amazon is offering a competitive price for authentic Denso re-manufactured (#210-0508) alternators.



*Note: In '04 model year, some early production LS's had the Denso #210-0508 alternator, and later production had the Denso #210-0570.

Tom57

Lexus dealer parts correctly shows the # 210-0508 alternator as being compatible with the 2001. Independent foreign auto parts also advised that the 210-0508 is the correct Denso (OEM) replacement. I concluded that the online websites are wrong, and somehow have a bad source for their listings - the bad source may, in fact, be Denso since their site is incorrect. (As noted above, there is a mounting difference between the #s 210-0508 and 210-0570 alternators. The # 210-0570 is a 4-pin connection, whereas the 0508 is a 3-pin connection.)

Summary of Denso Reman. Alternator Part Numbers

2001 - 2003 > # 210-0508
2004 > Either # 210-0508 or # 210-0570. If it's a 3-pin connector, then 0508; if 4-pin, then 0570.
2005 - 2006 > # 210-0570.