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There are a lot of anecdotal reports about when a timing belt should be changed. For the LS400, Lexus recommends 90K but obviously it will go further than that as Lexus does not want any belts to break at 91K or 100K (I have never heard of a belt breaking on these cars). Here are 2 pictures of the belt from my 91 LS400 (25 years old), changed 8 months ago at 133K. I changed it as the water pump was leaking (does Lexus build a lesser life time in the pump to force a change of the belt?). On my 02 LS 430 at 128K I change the belt 6 months ago, also due to a leaky water pump.
Shown are both sides of the belt. Small cracks are seen on the smooth side when it is squeezed and 2 teeth, 180 degrees from each other, were a bit frayed. There are about 10 teeth engaging the belt on the crankshaft timing pulley at any one time, so 1 slightly frayed tooth should not jeopardize the whole belt.
Yea, I'm personally in the boat that people freak out more than they should regarding the timing belt and age.
If after 25 years that's all the wear it's showing, I bet 99.9% of people would be fine waiting.
Unless it was REALLY old, I think you're fine waiting until 90k miles is actually reached and even then you have a lot of wiggle room. But I see people freaking out if the car has 50k miles and is 9 years old that they should tow it in and get it changed ASAP.
It's far more likely to snap because of a bearing seizing up then the belt breaking.
Shops LOVE to scare people into changing their belts as soon as possible.
All I know is I have done T belt and water pump always for the next owner to enjoy. At this point in my life out of the 7-9 cars we have in the stable at all times, our LS is the only one that requires a timing belt.
I know I am not changing it a day before 120K miles. If I sell it before then, so be it.
I know I am not changing it a day before 120K miles. If I sell it before then, so be it.
It's a hit-n-miss. Timing belt isn't the only component that cause itself to break. Not long ago there was an 182K LS430 UL for sale with a broken timing belt. Given that at 182K, I would speculate that the car had at least 1 belt replacement, which average out to be 91K per belt, before the breakage. Needless to say, I felt sorry for the owner.
I think the belt broke on that LS430 at 182K. Manufacturing cars is a complex endeavor and the parts must meet a given life time expectance. Lexus undoubtedly has the statistics on when belts break, mean lifetime, standard deviation (SD), etc. For timing belts to last at least the guaranteed 90k miles, I would expect the mean life to be 140k-150k with a small SD (indicating that the manufacturing is carefully controlled process).
Years ago I sought to get data on belt breakage by calling sellers of LS400, asking when the belt had be changed. Many did not know, some probably lied but one person had owned the car new and had not changed the belt with in 167K .
I am not advocating taking the belt beyond 90k, just adding my take on the subject.
I still have not heard of anyone with an LS430 with a broken timing belt. I'm sure although recommended at 90K wihich most adhere to 150K would most likely be safe as well. From all my reading, Lexus has chosen the half life of what they have decided the true fail period of our belts should be.. thus 90K (1/2 of 180,000 miles). Freaking out at 100K is unnecessary as the OEM belts are quite robust..
My belt (replaced at 93K) looked a lot like yours except I had no cracking on the smooth side. I did have those same two ribs with 'frayed' stitches on them. My new belt had that stitching on two ribs as well, but not frayed obviously. I'm thinking that that was not a big deal and is some artifact of manufacturing.
Whatever, though. It wasn't that difficult to change, cost was minimal and it prodded me to change trans fluid (most definitely needed) and replace spark plugs. Car runs exactly the same before and after. No 'smoother' shifting, no 'smoother' idle etc that people like to imagine they feel.
03-08-16, 10:01 AM
Pictures of my old timing belt
