At what mileage do you recommend replacing timing belt? And should I replace water pump at the same time? I currently have 99K on my LS430. Please advise.

Most water pumps come with a pulley already fitted. Replace the entire pump and pulley as the pump blades are plastic and wear over time. Most vehicle manufacturers recommend changing the pump everytime you replace a timing belt. If you are removing the belt to do this job swap the timing belt for a new one. Always a good idea on older and higher mileage vehicles.

you definitely need to replace the belt and water pump and sometimes the tensioner. i would recommend a high mileage belt and a water pump with a metal impeller.
failure to replace the belt immediately can cause severe engine damage.
believe it or not there is a youtube video that shows how to do the belt on a new beetle.

On these vehicles, the timing belt is recommended at 90K!! I recommend replacing the T-belt and water pump at the same time. The water pump is timing belt driven, and if it fails, you would be paying for another Timing belt service!! YOU WILL NOT experience drive-ability issues because the belt is aged or has not been serviced at its recommended intervals. Instead, if the belt fails, your engine will fail, and will require replacement or rebuilt ($3500+ job). Find a less expensive reliable shop thats experienced in EURO vehicles, and stay away from the dealer!!

The current smart thinking advice about Audi A4 2L manual timing belt water pump etc replacemnt mileage is 115 000 miles (180 000 km).

It is suggested by any mechcanic to perform this maintenace every 80,000 miles if you properbly maintain your vehicle. That mean going by the owners manual suggestions. Also I would highly recomend changing the water pum as well for it runs off this belt and water pumps only last as long as the belt will also. If a new belt is installed without a new water pump it may fail in no time. I seen it happen more than a dozen times in the past ten years

Recommended timing belt replacement.
90,000 miles
Note : This engine is an interference engine, which will cause major engine damage if belt is to break.Also good idea to replace water pump.

ECM CLEANED???? that sounds like some scam. It will need the timing belt replaced, and the water pump at the same time. You dont mention what engine and mileage? But if the water pump leaks, get it all done. Find a Independent Shop that works on Toyota.

Most car manufacturers recommend replacing timing belts after 60,000 miles. I have seen cars go 200,000 on a timing belt. But I wouldn't recommend that. Personally, that Max I would go, even if 99% of your driving is highway, is 80,000 miles. I'm not 100% sure about the sonata, but if it is front wheel drive and your replacing the timing belt, think about replacing the water pump at the same time. That is always good practice to remember.

every 90,000 to 100,000miles and yes it is strongly recomended to replace the water pump with it

90000 Miles on the Timing Belt. Do not let this go! A timing belt failure can cause internal engine problems.

Should cost around 200 or so, depending upon your local labor rates.

Good Luck!

Brian