LEXUS ES300 Timing Belt

I am a senior citizen and own a 1999 Lexus ES300 with a V6 3000 Four Cam 24 VVT-i engine with approximately 102,000 miles. There is an ongoing problem with the car that the dealer’s service manager and master mechanic cannot figure out. Within the last 3 ½ years, I have driven my Lexus less than 15,000 miles and had 4 timing belts installed. The last timing belt was installed in September, 2014. During this time the tensioner, idler pulley and crank pulley have been replaced. The noise keeps coming back within approximately a year or 5,000 miles. I met with both the service manager and master mechanic and asked them if this was their grandfather’s car what would they advise him (besides getting rid of the car); the master mechanic stated he would tell him to just keep driving it. I am very concerned and want to know why this is happening. Any assistance would be greatly appreciated. Thank you.

Usually when the timing belt is replaced on these engines a timing belt kit is installed.

Was the water pump also replaced?



Please describe this noise

The water pump was replaced with the first timing belt replacement along with all the other belts. Thanks for asking.


Please describe the noise

It’s good that you’ve replaced the water pump

The noise sounds like a worn idler pulley or belt. After replacing the belt the noise goes away for approximately 5,000 miles or a year. Thanks for asking.


In my opinion, it sounds like the noise may be coming from the accessory drive belts, and not the timing belt. I would make sure to replace those belts with Toyota brand parts

I’ve seen it often, that aftermarket accessory drive belts are noisey, whereas the factory part was not. In some cases, the aftermarket belts are made of a slightly different material. I’m not sure if that’s a contributing factor

I agree with what you stated. I asked the dealer if he was using OEM belts and parts and he assured me he was. Before replacing the timing belt they remove each assessory belt one at a time to make sure it’s not one of them making the noise. Thanks

Why not try another mechanic next time?

The Lexus/Toyota dealership has had other mechanics work on the problem and they turned it over to their master mechanic who could not find anything wrong and he replaced the timing belt and once again the noise went away. They even checked their service bulletins for such problems.

Do you know the condition of the belt when it comes off? Does it show any type of damage or is it just making noise? The only thing I can think that may be causing a problem is if one of the teeth on the crank or cam sprocket has been damaged. I have seen cam sprockets damaged by holding them with large channel locks instead of the proper tool. Beyond that this is a simple belt to do and should last without issue for 100k.

You might try this. With the engine running and the noise present use a spray bottle of water and hose the accessory belt down a little to see if the noise goes away; even if for only seconds.

If you don’t have a spray bottle for water a shot of glass cleaner should work. This should show you if the problem is related to the accessory belt or not.

The accessory belt has to be removed to access the timing belt so maybe something is changing with the accessory belt after being reinstalled and the timing belt is erroneously getting the blame.

@insightful makes a great point. Just take your Lexus to a good independent mechanic and insist on a high quality belt, water pump and kit. Something is wrong if the noise keeps coming back.

I want to thank everyone for their comments. The crank pulley has been replaced, the cam pulleys to date have not. I have not seen the timing belt when it was removed (my mistake) as the dealer lends me a car and I leave. On the invoices it states timing belt noisy and on only one invoice timing belt nicked where they also replaced the crank shaft pulley. In September when the noise returned I brought the car in and I waited for the car while they assessed the noise. I was told the master mechanic sprayed the accessory belts first and then pryed the timing belt cover back and sprayed a lubricant inside it and the noise went away. I was scheduled the following week to have it checked out further and repaired. When I returned home approximately 10 miles the noise was back. A week later the timing belt was replaced which also included replacement of both cam seals. The mechanic stated one was leaking a little. I reminded him that he sprayed a lubricant in there a week ago. I also asked about perhaps using a better quality belt which they stated they only use Lexus/Toyota OEM parts. I agree with all the comments and I assure you the next time it happens I will have the dealer call me when the car is apart to see for myself. The dealership is honorable and I have been dealing with them for over 15 years. They are stumped by this as well, therefore, I decided to join the car talk community.


You’re certainly providing us with all the right information, and you’ve asked the dealership all the right questions.

Even though I don’t have your car right in front of me, I have a hard time believing the timing belt is the source of the noise.

The reason I’m not really believing it its because a timing belt does not ride in grooves, unlike an accessory drive belt.

For what it’s worth, somebody once tried to tell my brother that his timing belt was the source of the noise. It was actually the accessory drive belts

You might ask the Lexus people this…“Do any of the car models they are selling today still use the rubber timing belt??”

Toyota/Lexus has not used a belt in their engines for many years.

It seems that the Lexus forum has several posts concerning timing belt replacement noise. Here is a post that may help.

Several Ideas:

  1. If you over-torque the PS pump pinch bolt, the pump will make a whirring noise when re-assembled. I had this happen last week on a T-belt. I had loosened it fully and pushed the ps/vane pump aside to get clearance to get at the tensioner bolts. I over-torqued the pinch bolt when re-installing. (Pinch bolt is the blind one over the pump, not the two visible ones on the adjuster bracket). When I heard the noise, I realized what I had done wrong and I went back down, loosened it all up and re-torqued it in sequence to correct values and the noise immediately went away. I have a strong suspicion this is your problem based on your good description.

2nd option (as mentioned) is that if you have a weak bearing, it will get worse with a new t-belt and ac/alt belt. Mine did that too, and I had to go back and pull the alt. and re-build it (only $30 w/parts from a local auto electric specialty shop - I was totally unable to find a rebuild kit or bearings from any other source).

3rd thing is, if the thing is if a tooth off, it will screw with the ECU/ECM/PCM (whad eva ya’ wanna call it) signals to the VVT-I gear and the OCV will be out of synch. This will make an unholy racket asap, however this would clearly be noise coming from the valve gear and not down low.

4th, if Someone who does not know this engine did it, and they pulled the rear cam pulley off, two things could have gone wrong:

PS, unless you are a licensed cardiologist AND ASME card-carrier, don’t trust what you think you hear through your steth. I have a decent stethoscope for engine/mechanical use. My dad has two, and is a former professional motorcycle mechanic and racer, and diesel mechanic and machinist. I went to med school and got trained by top cardiologists at UW with my fancy “Littman Cardiology III” stethoscope to find the slightest murmurs. I was good; not tops in my class. But still, unless you get the cheap(er) mechanics steth on the exact right part, you will hear transmitted noise and easily misdiagnose it. He and I make mistakes with the stethoscopes often and between us, we should be as good as the very best professional mechanic.

The issue is we aren’t bad, the thing is the resonance of steel all firmly bolted together means the sound travels so much and so efficiently that you can easily be fooled.

a) it is not installed the same as the front bank pulley, the belt lip is reversed vs. the front pulley (same part, just installed backwards - kinda counter-intuitive). Lip could be grinding on back shield or front cover. I do not consider this likely as it would be self-resolving pretty quickly.
b) did not tension rear cam pulley bolt correctly and pulley loose. Again, not the most likely as it would lead to other problems first.

Hope this helps.

Read more:

DB4690: – When the noise comes back and the dealer determines it’s the timing belt; I will take your advice and have the dealer’s master mechanic put new accessory drive belts on also.

Knfenimore: – I did not know about the Lexus Club Forum. It appears I am not the only one with this problem and it has others frustrated as well. I only wish there was a conclusive answer.

I really appreciate everyone’s comments and I am also hoping perhaps Tom & Ray will weigh in on this also.

@Cargeezer, Tom and Ray retired. And, they did not participate in our little forum here while they still were active on the show. So, basically, we’re all you’ve got.