I think this is my first post but have been hanging around and reading alot.

I just bought an 02 SC430 with 23K miles. This car really looks and runs brand new. I question the change interval for the timing belt. 6 years OR 90K miles which ever is first. My car has 23K miles. There is no way the belt is in need of changing even after 8 years and only 23K miles. How does Lexus come up with this one?

The other timing belts I have replaced were all mileage determined and after 90K miles those belts looked brand new so whats the deal with the time limit? What if I bought the car brand new drove it home and parked it in my carport and then now today I have 100 miles on it, would the timing belt need changing? I don't think so!

 

I'm a bit of a lurker too, and just today read a post from someone whose timing belt broke. It did a lot of damage to the engine. Their car did have more mileage on it than yours, but it was I believe the same year.

Are you familiar with the term, 'interference engine?' The SC's engine is one. When the belt breaks, the valves can go down while the piston goes up, and they'll smash into each other. That causes a lot of damage. Other engines have clearances designed into them so if the belt breaks the engine will just spin to a stop without damage, but the SC doesn't.

As I understand it, the timing belt is more age-limited than, say, the water pump, which is more mileage-limited. I'd humbly suggest changing the belt, but see what others have to say.

I also read somewhere that the newer SCs have the interval increased to nine years, so even under those circumstances you're getting close. But, like I said, don't just take my opinion.

 

First off, congratulations on your new ride and welcome to the forum.

The belts actually do age. Sometimes they may actually last longer but other times they do age and crack. You do not want the timing belt to fail! The SC430 engine is an interference engine, meaning that if the timing belt fails, you will likely ruin your engine because the belt keeps everything moving in such a fashion to prevent collisions inside the engine which result in bent interior metal and broken pieces. This is an extremely expensive repair to have to make.

However, later models do mention longer than 6 years. The question here is whether Lexus actually changed belts, or did the belts start getting made better or do they now have better performance information on the belts. Personally, that wasn't a gamble that I was willing to take with my '02.

Let us know how it goes and good luck.

 

First, if you've been reading a lot you've stumbled into timing belt discussions here before and you know the rationale. Certainly, you can take any position you like regarding the effects of time on rubber compounds and belt fibers. I am one who replaced his timing belt ('02 SC at 37K miles) just to be careful. I did the work myself and was amazed at the condition of the belt I removed. The rubber appeared to be in about the same condition as the new one, and about the only difference I could tell was slight wear on the inside of the teeth showing some fibers. There was no noticeable accumulation of rubber or fiber dust in the covers. Idlers, tensioner and water pump appeared new. The way I look at it I didn't spend over $200 and I feel a lot better every time I turn the key.

I can't confirm that the PN of the timing belt changed over the years but the maintenance recommendation did increase in about 2005. For comparison you might check out what tire manufacturers recommend about aging tires.

Congratulations on your purchase of a great automobile and good luck with whatever you decide to do with the timing belt.

 

Do a search...been talked about a bunch and general consensus for most in your situation was that they did go ahead and change it. I would...consider it an insurance policy on your great investment!

 

As others have mentioned, it a peace of mind issue, or an extended warranty issue. What was that, you don't have an extended warranty. So I guess the question is peace of mind over the manufacturers maintenance recommendations. Good Luck and welcome to the forum...Please post some pictures of your new car.

 

It sounds like you have hit the jackpot! How much did you spend for this very young 02?

 

I too was one who was very skeptical that our '02 SC with only 15K miles on it when I bought it should have the belt changed. I had it changed recently at 36K miles. The water pump was starting to weep (very slow leak). The mechanic told me that the water pump on cars that don't get driven a lot tend to do that because the seals dry out.

For $700 at a local independent shop I now have all of that behind us for the next 90k miles.

Change it and be done with it.

 

I was shocked when I first saw the car, we had seen/driven other 02's and when the guy drove up to meet us the car looked brand new. It's 4Q8 Egyption Sand Pearl(GOLD) and Ecru with Birdseye Maple. The guy was asking $26300 and I offer $22500 based on the other 02's I had looked at and he took my offer. I will post pics when the sun comes back out here.Gloomy!

 

I am one who replaced his timing belt ('02 SC at 37K miles) just to be careful. I did the work myself and was amazed at the condition of the belt I removed. The rubber appeared to be in about the same condition as the new one, and about the only difference I could tell was slight wear on the inside of the teeth showing some fibers. There was no noticeable accumulation of rubber or fiber dust in the covers. Idlers, tensioner and water pump appeared new. The way I look at it I didn't spend over $200 and I feel a lot better every time I turn the key.(QUOTE)

I can't confirm that the PN of the timing belt changed over the years but the maintenance recommendation did increase in about 2005. For comparison you might check out what tire manufacturers recommend about aging tires.


Thanks for this post. This is exactly what I was talking about. The two other belts I replaced at 90K miles on other vehicles looked like you have described. No significant wear.

I questioned the timing belt change to the previous owner and he said the Master Mechanic at the local dealer said that with 23K miles even though the car is 8 years old would be fine. Now I happen to personally know this mechanic but I haven't talked to him yet. This Mechanic has been with Toyota/Lexus 28 years and the previous owner said that only this guy worked on his car.

I don't know, I trust these belts(if no out of the normal operation like contamination) and wish I knew more about the time issue that even Toyota themseles doesn't have a time limit on there vehicles that I know of??

Just something for me to investigate more and think about I guess.

 

To add a little to my earlier comment, I was unsure about how quickly wear will occur on a timing belt once it begins to deteriorate. The fact that there was little noticeable wear on the inside of the belt was somewhat comforting, but I have seen a lot of unstressed rubber components on a vehicle go bad over time. So when I weighed the relatively low cost of replacing the belt against the risk of a catastrophic engine failure I decided to do the work. In the beginning what got me to thinking more seriously about the timing belt was the condition of the serpentine (accessory) belt on the same car - it was original equipment - but cracked and dried. Granted it lives in a more hostile environment than the timing belt but I reasoned that 9 years after the build date the timing belt condition couldn't be far behind.

Incidentally, there is a post on this forum from an individual whose timing belt did fail. It will give you some additional perspective.

 

The belt which is rarely used will likely fail over time, rather than the belt which is used daily. Makes sense?

Belt which sit for months, then used, then sits again will likely have uneven stress on stress versus a belt wich is continually used every day. JM2C.

Hence daily ride cars survive longer than cars whic sit on the garage more than half their lifetime. Again JM2C.

 

A lot of good information here to the OP. Rubber (and other ingredients) being the key word. Piece of mind is so nice.

 

The newer manuals (my 2007 manual, for example) states 108 months or 90K miles - Did they upgrade the belts several years ago, or just have more information on failure rates available and change the recommendation?

 

Do the service. Currently going rate for a used engine on ebay is 4k+