Rich S, I Need To Change My Alternator

ToddLS400 · August 18, 2003

Rich, how long did it take you to replace your alternator. I'm pretty sure mine is going out. I can hear a faint chirp once in awhile from the alternator and I see a some PS fluid caked ontop of it. When I drive sometimes the battery, brake, oil, etc lights come on in the dash for no reason. When I rev it up they go away after so many RPMs (6K+?). Then it will do it again later. Today it did it quite a bit. It was annoying. I think the alternator is about to give up the ghost?

Do you have a online step by step that you can point me too? I replaced some stuff (alternator, radiator, theromstat<-that was harder than it sounds) on my old 300ZX's which was difficult. I got use to the cramped space and I did a lot of my own work on my Z32. I have a '91 LS400 shop manual that I'm borrowing from a friend. I'll look thru it tonight. So I need to replace the O ring on the PS pump then replace the alternator. That is a bad place where they put that PS pump. A design flaw by Lexus. I'm sure it has to do with limited space more than anything? There are not too many flaws on the LS400 but the placement of the alternator and the starter is 2 of them. The starter is buried in the back, rear of the engine. As you know...

I looked in the manual tonight and it looks fairly easy:

1. Disconnect battery

2. Remove drive belt:

Remove raditator upper hose, Loosen drive belt tension by turning belt tensioner clockwise, remove belt.

3. Remove engine under cover plastic

4. Remove alternator from beneath - unhook +/-, unbolt

I want to fix the PS pump O ring when I'm in there as well. Do I do it from underneath after I remove the alternator?

ToddLS400 · August 18, 2003

I just went through my receipts from previous work that the ex-owner has done. The alternator was just replaced and reman'd a year ago (6/02). It has a lifetime warranty so I'm bringing the car back to that same shop. I just called them and the mechanic said that I have to pay for labor (R&R) though. The last time it was done it was 1.0 hour labor on the old invoice. After looking at the manual it does seem like a pretty simple job? At least something is easy to replace on this Lexus. I guess I'll just pay the labor and get another reman'd alternator? I wonder if he'll complain about the PS fluid ontop of the alternator?

SW03ES · August 18, 2003

Clean it off ;)

Its possible the leakage from the o ring could be fouling the alternator...

ToddLS400 · August 18, 2003

Clean it off ;)
Its possible the leakage from the o ring could be fouling the alternator...

I know, that's I what I'm assuming. But....I just went to the shop and they tested it and it came out fine, about 14 volts. Hmmm... The stupid dash lights didn't come on when idling either. He said if the alternator was going bad then the battery light would come on only. It always seems your car never shows any symptoms when you actually bring it into the shop? Jeez...

The owner said the previous people that owned the car did just enough to keep it going. Not good... He said when they replaced the alternator (w/timing belt and waterpump) last year the dash lights still would come on once in awhile after the new alternator. He said to go have it looked at by a electrical shop when it happens again. I hate electrical problems. He also showed me on the work history how the starter began to go out back in 6/02. They drove it for over a year with a faulty starter (worn contacts). It cost me $560 to fix and replace the starter contacts(cheaper than most). A lot of labor fishing the starter from the bottom, back end of the engine.

Has anybody run into anything similiar like this? Does anybody know of an electrical troubleshooting site for the LS400?

SW03ES · August 18, 2003

See this is why it'd be nice if the LS had a voltage gauge...

Its possible that the alternator is systemically allowing the volts to run low. This actually isn't at all uncommon, and if the shop didnt hook up a voltmeter precisely when the problem was taking place, then there'd be no evidence of anything wrong. Its hugely irritating. I had an on off problem with the alternator on my Explorer for a month. It'd get low and the lights would come on, I'd race to the dealership, by the time I got there it'd be normal. I'd pull out, it'd happen again, I'd race back it'd be normal. FINALLY they spotted it on a test drive themselves.

It definately sounds like the alternator though, off lights, goes away with RPM, sounds textbook...

ToddLS400 · August 19, 2003

See this is why it'd be nice if the LS had a voltage gauge...
Its possible that the alternator is systemically allowing the volts to run low. This actually isn't at all uncommon, and if the shop didnt hook up a voltmeter precisely when the problem was taking place, then there'd be no evidence of anything wrong. Its hugely irritating. I had an on off problem with the alternator on my Explorer for a month. It'd get low and the lights would come on, I'd race to the dealership, by the time I got there it'd be normal. I'd pull out, it'd happen again, I'd race back it'd be normal. FINALLY they spotted it on a test drive themselves.

It definately sounds like the alternator though, off lights, goes away with RPM, sounds textbook...

Yeah, I know. It drives you crazy. The car was doing it all weekend too. It even did it this morning after starting it up. I got on the freeway then I arrived at the shop then it all of a sudden was fine. Huh? I just started it up about 15 min's ago and it now seems fine. What gives?

I'm going to spray Simple Green on the top of the alternator to disperse the ps fluid like you said. I'm kind of dumbfounded to be honest. If the alternator is going out you would think it would be consistent? But going by your expereince with your Explorer, I see that it is not. I know it's that stupid ps pump leaking ontop of the alternator causing havoc. I need to know how to change out the O ring on that thing so it stops leaking. Thanks...

SW03ES · August 19, 2003

Naa, alternators aren't consistent. They kinda flunk around like that then just die. Maybe try fixing the O ring and see if the problem goes away...unfortunately I havent the slightest clue how to do that lol.

ToddLS400 · August 20, 2003

Jeez, the dash lights haven't come on over the past few days. Maybe it's some kind of electrical issue? One thing that baffles me is when the dash lights would come on, the cruise control would turn off on the freeway. I felt no loss in engine power or anything like that. I've been driving the Lex and burning my own gas when I should be driving my company car with free gas. Gas prices have shot up.

Oh yeah, I put more coolant in the system after seeing that orange light. I didn't add that much though. It looks like the only place to add water or coolant is at the overflow reservoir? I didn't look all the way under the plastic shroud that covers the radiator though. I haven't seen the light since.

LS400Convert · August 22, 2003

I went through the alternator thing a couple of months ago. Here is the thread that discusses my problem and eventual diagnoses and fix. Your's sounds a little different, but at least this might help. :cheers: