LeX2K

Here's what happened to me. Replaced original belt* using the Aisin kit. As soon as I did had the noise, only happened when the engine was warm no noise when cold. Thought it was the idler, replaced of course no difference. Replaced belt with Toyota OEM, slightly less (maybe) noise. Got frustrated and eventually realized there was gunk on the cam gears cleaned them and used a Dayco belt. Noise gone.

What I didn't try: putting the Toyota belt on with the cleaned cam gears. I did put the Dayco belt on before I cleaned the gears, noise much less.

*given the age of the car I was told to replace the belt even though it was not due if factoring in mileage. This was a huge mistake there was nothing wrong with the original belt at all. I don't buy that a timing belt goes bad with age. Further proof of this is I recently installed a JDM engine (1990) the timing belt was original. Since it looked perfect I left it alone, didn't change any seals either. The engine leaks no oil and has since driven about 40,000 miles no belt failure. To me this says modern rubber compounds do not go bad with age as some keep insisting, well they do but takes many decades.
Agreed.

BTW this problem is not limited to the 1MZ/3MZ I've had it happen with 4-cylinder Toyota engines although the problem is not as bad since there is less belt material and only one cam gear.

funcrusher

How much are these parts from the stealership? Might be worth it biting the bullet and getting everything from there. I’ll probably use Lexuspartsnow when it’s time to do mine.

June1978

exactly my symptoms- I was very hesitant on changing the timing belt- I bought the car at 184k from the original owner. She had all the maintenance records with flawless history. All work done at Lexus. The timing belt was done at 90k and I thought with 184k it would be good to change the belt etc and update all the maintenance for my own peace of mind. When the mechanic showed me the belt that had been on the car since 90k, it was in great condition. Even he said I could have drove the car for much longer but it was good to follow the scheduled maintenance schedule.

My car currently sways on the highway with high wind. I'm being told struts and sway bars need replacing. Again, I'm hesitant on replacing parts, especially using aftermarket. I'm reading that Monroe, Moog and KYB all have their issues and could lead to clunking noise on our cars. I looked up OEM and they are $600 each. bummer. I might hold out as long as I can until they really start to show signs of failure.

June1978

Lexus parts now has everything you need. The belt was $54, water pump is $130, the idlers are $90 each. I may be wrong but the Aisin kit is ok as long you don't use the belt that comes with it and get OEM (as you can see why)- Aisin kit is $153 on rock auto

I only bought aisin because thats what was used and recommended by many members on this forum. If I didn't do my research i would have just gone OEM for everything. About $400 for OEM parts and $400-$500 for labor- not bad- you only do it once every 90k miles anyway

LeX2K

The Aisin kit has the same parts as OEM except the belt. All the other parts are identical, well the water pump might have the logo ground off. I have several times used the Aisin kit with the Dayco belt since it is only $14.* Will be very interested to see if a new Toyota belt along with new cam gears cures the problem. In theory this should 100% be a fix.

* again will issue caution it's been a while since I bought a Dayco belt so the manufacturing may have changed. I'm thinking not but it is possible.

June1978

Thanks- I'll keep the forum posted on the outcome. I'm set to go back next Saturday. I'm going to sit there and wait for the car. (and watch him replace the parts)

artbuc

I have installed many Aisin kits and never had a single issue. Also never heard of anyone needing to replace cam sprockets to eliminate noise. Not saying that isn’t your problem but have been reading automotive forums for decades and never came across it.

June1978

Not sure- reading some of the older posts in this forum and the comments in the youtube videos I posted, all fingers point to the actual belt. Not sure if its a common issue but enough people have complained about this noise after a timing belt install for enough data to be present in regards to the issue being the actual belt

One youtube user said he sprayed water on the belt as a troubleshooting step and the noise went away so he was certain it was the belt- I may have my mechanic do this next week while I'm present to try to pin point if it really is the belt or not

Lexus2000 said I could clean the pulleys but it looks like a very simple install and a cheap part so i might as well do both pulleys and use an OEM belt. If that doesn't kill the noise, I give up. Apparently some people drove around with this noise and never had issues- just an annoying noise that to be honest is really apparent when you lift the hood. I was just worried that this may lead to something catastrophic but it doesn't look like that is the case

June1978

Update- replaced the camshaft sprockets and used a genuine toyota belt and no more noise. Picked up the car and drove it around for 20-30 minutes and the timing belt noise did not return.

Not sure what the primary issue was- the actual belt itself, the sprockets or combination of both. Most of the comments I read on the youtube videos mentioned the issue was resolved by using a genuine timing belt- one user stated the noise is not the belt and instead the sprockets. I took Lexus2000 advice here and replaced both sprockets and used a genuine belt

So yea all fixed. Like I previously stated, this may need to be stickied considering that there are many lexus/toyota owners facing the same issue after a timing belt replacement

cam sprockets- $35 each (need 2)
genuine toyota Timing belt- $44

LeX2K

Good to hear. I've argued with quite a few people over this they refuse to believe a new belt can make noise. Well it does unless you clean ALL the old belt material fused to the sprockets, or replace them which I think is the way to go.