OldLs400

How hard is replacing the alternator on a 98? I'm pretty sure the alternator died because my dash lit up like a christmas tree with random error messages like ABS, VSC OFF, etc suddenly after the low battery warning light came on. My PS pump has been leaking, and I had to top it off recently with some stop leak. It stopped leaking after the stop leak, but I'm afraid the damage has already been done.

Does anyone have any instructions for how to replace the alternator on a 98? I read that the 98-2000 models are much more complicated to work on with regard to the alternator than the earlier ones.

Would replacing the alternator in a parking lot at work be feasible? I don't have a garage to work in currently, only a parking lot.

Scraape

you could absolutely replace the alternator in a parking lot as long as you have correct tools.

You just have to take off the power steering pulley to give you enough clearance

OldLs400

Thank you so much. Do you have a diagram of something with all the steps? I'm also unsure what the power steering pulley will look like. Is it a case of I'll know it when I see it? Any special tools required?

Michael88

Importantly, is the power steering pump leaking on to your alternator? They all do. I just did mine and I am a 48 year old self maintaining my vehicles ever since I started driving. This job is the hardest alternator I have ever done. It can be done in a parking lot, but be sure no one can back into you while you are under the car. If that were to happen you would get crushed. Also, most people have to change both the power steering and the alternator, otherwise the alternator will just get soaked in power steering fluid again. It would need replaced next year, too. The job requires upper arm strength as there is a lot of "tight" spaces doing the job from underneath the car. If you are so lucky as to not have a leaking power steering pump, then I would not try taking the power steering pulley off. You run the risk of warping that pulley and having to replace it. I have successfully taken the bolts out the side of the power steering pump. Backed the front bolt out as far as it will go and slid the pump forward so the alternator can clear the pulley to come out. Hope this helps. And do be careful in a parking lot. People back into cars all the time. Have it double jack standed and wheel chucked. Even better yet, do the job in a driveway or garage.

OldLs400

Thank you so much. I heard of your alternate method of backing out the pump.
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what year was your ls?

Michael88

I have a 1998 LS400

OldLs400

Awesome. For some reason I read that the 98 LS400 is MUCH more difficult to work on than earlier models. One person mentioned that he had to remove parts of the radiator like the fan shroud AND THE UPPER RADIATOR HOSE (!!) just to get to the alternator. Does this sound like BS to you? I don't want to be refilling coolant and burping the cooling system in addition to replacing the alternator.

https://us.lexusownersclub.com/forum...on-1998-ls400/

Michael88

I didn't have to remove the fan shroud, but I did have to unbolt it and be able to move it around a little bit. Be careful not to rub the radiator coils, though. I didn't have to remove any hoses, but I did have to press against them, a lot.

bradland

Ideally the alternator is removed from underneath. It can be removed from above as well, I've done it both ways, which requires removing the fan shroud. There's not much room to wiggle it out from above, you end up dragging it against your radiator a bit, but it is possible. Quite often approx 80% of your time will be spent unplugging the electrical connector as it tends to get STUCK. The last time I did the job it took about an hour...

bradland

Just 2 bolts holding it on. PS pump pulley, top left in the pic, has to be removed to allow clearance when removing.

OldLs400

Complete noob question, but to remove the pulley, I just loosen the bolt in the center of the PS pulley? Is the bolt a standard right-hand thread or something weird? And is it possible to replace the fan belt while I'm at it?

Michael88

I am not sure, but I think it is standard thread. It is 100x harder to that pulley off with the pump on the car. You will have to stick 3/4 in pipe or heavy gauge screwdriver or something like that into the pulley holes and wedge it into the casing of the pump or block in order to keep the pulley from turning. Not only do you have to do this taking it off, but also when you put it back on. Trust me. Take the two power steering pump bolts to the engine block out from underneath the car, then back the front bolt all the way out and slide the pump forward letting it rest on that single bolt. You will need an assistant if you take all three bolts out, and this might be easier if you have one. Just have them hold the pump from above when it is time to slide the alternator out. This is a great time to change the fan belt.

OldLs400

Thank you so much. Do you have a picture or diagram of the power steering pump bolts so I know where they are ?

bradland

Sorry but I have to disagree- the PS pulley comes off very easy. Leave the PS pump where it is no need to do the extra work AND you def don't want to disrupt the PS hose by moving the pump. The nut holding the pulley is regular thread. Slip something through one of the pulley holes to keep it from turning and you'll have it off with very little effort.

Michael88

This was not what I experienced. Knuckle busting trying to keep one hand on a screwdriver wedged into unforgiving casings and turning a socket with the other all while trying not to gouge the radiator and warp a pulley is a gambler's choice. However, you do need an angle adjustable socket wrench if you take the bolts out and slide the pump forward. If you don't have one, then you may have no other choice but buy one or gamble.