How Can You Tell The Alternator Is Worn?

[Tallguy196]

Greetings to you all!

I´ve been a silent wiever of this mb for some time now. It´s very helpful and some of you share a lot of useful information, I thank you sincerely! Beeing a proud owner of a LS 400 ´92, unfortunately in Sweden, where the shop fees are ridicoulus, I´ve found your hints and tips very useful. :D

Now to my problem: Suddenly, 5 warning lights glows on the dashboard.... They disappear when I rev the engine to approx. 3000 rpm, then they come back. Today, while driving home in the dark and the snow, 2 more warning lights came on, the ABS and the TRC.... everything flickers and the engine is not running as smooth as I'm used to...

Yes, I have the standard leak of P/S oil, can the oil damage the alternator? Or can it be the brush or voltage regulator?

The car has 1677702 miles, (276000 km) and nothing has ever been done to the alternator, to my knowledge.

Any help appreciated! I beg your pardon for the lousy english

Take Care!

/Lasse

[GreyBeard]

First, welcome to the club - i too have found it useful.

Second, glad you gave the mileage in kilometres, otherwise at over 1.5 million miles we could have put it down to old age!

Third, a couple of guesses: a poor earth, possibly between engine block and chassis, or a low output from the alternator - somewhere in the club i've read detailed instructions for checking this, but a reasonable volt meter should give you about 14.4 volts at the Battery terminals with the engine running about 1000 rpm, and about 12.6V 5 mins after you turn the engine off. if you're not getting 14V or so when running, is the drive belt loose or oily?

if it's not these, maybe someone else has a view?

[Monster-Mat]

is there oil contamination on the alternator, i seem to recall that alternator faults on the LS can be caused by oil contamination due to its location...

[obergc]

Alternator failure caused by leaking power steering fluid is a VERY common problem. If you look in the picture gallery you will find a picture of a clever shield designed to keep the leaking fluid from getting inside the alternator. Leaking power steering fluid is best taken care of sooner rather than later.

Curt

[obergc]

here is a link showing a shield for your alternator that one US member has fabricated.

Curt

http://us.lexusownersclub.com/gallery/LS/Alt2

[GrandAlf]

Could be just the Battery?. Try jump leads from another car to see if the problem dissapears. Worth a try, it costs nothing ;)

[Jason 92 Mk1 LS400]

I had exactly the same problem, it turned out to be the alternator - go along to a local "quick fit" or similar and ask for a free check - they can check the output from the alternator which should be approx 14V - I think you will find yours less than 12V (hence the lights comming on) - Get it fixed, straight away - unlike me - you ever tried puching one of these :shutit:

[Tallguy196]

Hello again!

I wish to thank you for your replies and support! Yesterday, me and my friend took down the alternator completely. It was´nt that difficult if one follows the instructions found on the US mb. I had already purchased the brush and holder, mostly because it was the cheapest part.... ;)

We took the alternator apart, VERY greasy from the P/S oil leakage, (I took some pics but I don´t know how to upload them) and located a VERY worn brush and holder. (Remember the mileage..) But, sad to say, that was not the main problem.

Due to the P/S oil leakage, a build-up of grease and small particles wear down the rotor copper paths........ and a rotor is quite expensive... that´s why they change alternators.... To keep a long story short, I´ve now ordered a swap(?) alternator from Toyota....It will arrive on tuesday! Keep your fingers crossed! By the way... The Nippon Denso alternator in the LS exist nowhere else in the Toyota family....

Thanks again for help and support!!

Take Care,

Lasse

[Scorpion]

Maybe worth fitting the cover when the new one arrives.

[soramad]

the cover is available through any good toyota dealership

i am looking at an exploded drawing of the 12v 120 a alternator and it would appear that everything internaly is replacable , however the part that is of the most importance when you have sorted your problem out is a cover the part no of which is 27029-46010 there is also a part no 27039 2of which i am not sure about but appear to cover the plastic connector end of the alternator but the parts people will be able to clarify that . this is something i intend to be doing in the very near future for my soarer /sc400 , the cost of the part is at the moment an unknown quantity as i think it has to be shipped in but you may be lucky and find one on the shelf , or via a breakers