Honestly I can probably change a timing belt on an ls400 in about 1 hour now with all the tools with about how many times I've torn it down. The noise is difficult to hear but much more noticeable in person I tried my best to record it. It also causes a slight vibration in the steering wheel in park. I will plug in the radiator hoses and fill the reservoir before I run it. Just trying to get it to sound right again. I felt like I've done a lot of testing and just haven't been able to narrow it down. Hard to fix something that you can't see. I wanna drive the damn thing instead of letting it sit. I love driving it.

 

If you still have the old belt and pulleys etc u could swap out the new ones and narrow it down that way. Also check that new crank shaft seal, just make sure it was fully seated when installed. I really think the culprit will be creating dust and debris from whatever is getting chewed up

 

Sadly threw away the old tensioner or and pulley but I do still have the belt at least. I will throw the old one on and clean the sprockets and make sure the crank seal is seated well.

 

You can replace components all day and night if you don't either clean or replace (better option) the cam and crank gears you'll never get rid of the noise. But you're welcome to try, future you will think about this post and wish you had considered it.

 

Oh no I plan on cleaning the crank gear and cam gears while the belt is off. Probably won't replace just yet but I'm gonna clean the **** out of them.

 

That might not work 100%, or you'll clean them so well (oven cleaner) it removes the protective coating. That happened to me noise was gone but was afraid the gears would rust.

 

I was planning on using a strong rubbing alcohol with a hard bristle brush. Something to get the gunk but not be to abrasive will try my best.

 

I am pretty certain the gears are all brass or aluminum, (non-ferrous) and won’t rust. And any coatings would probably be to keep the belt from ever sticking if the belt got contaminated with oil or extreme heat even if parked for a long time.
I replaced my T-belt at 189k miles, and didn’t have trouble but I didn’t do my cam seals.
So I bought a kit with an Aisin water pump but the belt was a Mitsuboshi brand, which I confirmed was OEM, it sounds like this would be what yours is?
U can figure it out today, don’t give up, don’t put those timing covers back on til your confident it’ll be the final time, you can get a stethoscope that’s helps u pin point the source of noises like this, they are only $10 at a parts store or Walmart. Inspect everything that moves and hopefully it’s not inside the water pump or something.
Keep us posted

 

Well I'll be! Quite a coincidence Thank you for this.
I'm not going to tell you what I have done recently to try to find a noise like this in my car.
Ok , I will swallow my pride and tell you all.
Serp belt
Serp Idler
Clutch fan
Still had noise.
Timing belt
water pump
idler
tensioner
Still noisy
Hmm. Maybe it's the transmission.
Swapped trans with local CL part-out .
That seemed to do the trick for a while but I think my mind wanted to not hear it after that. Noise has returned.
Next items will be new cam and crank belt gears.

Thanks again.

 

So update on this. I ended up having to delay many things due to the Hurricane here in Florida. I cleaned the cam gears and crank gears put the old timing belt on and still the noise exists. It sucks but I think I just might have to live with it until I can hit a junkyard to find new to me gears. Until then I'm just going to drive it. Sick of having it permanently parked. I was going to focus on trying to see what was causing the noise but the Hurricane was coming and I decided to put it all back together as to not take any chances with me flooding the car out. I needed to move it to higher ground. Initially when I threw it back together it did sound a bit different but as soon as it warms up the noise still exists. The vibration seems to have lessened in the wheel which is nice. Hopefully I will find a car near me with the gears. Then i'll give it a go again.

 

First off, sorry to hear your area got hit by Ian. Well wishes to everyone effected. It'll be built back up better then before, just like it has in the past. But glad to hear you're ok after that disaster. In the past I moved down to Ft Myers Beach after Andrew hit, (cuz I had family in the area) but ended up coming back up north. I'd rather deal with the snow.
As for your car, good luck trying to find the noise. Like I said, I can't even hear it in the video. Take care of your other stuff first getting things back to normal to live. At least the car's drivable.
Good luck, thinkin' of ya.

 

Any update on the noise? My ‘98 LS400 also makes the same noise for some reason.