coolant leak

Find the leak, if external? Radiator--hoses--heater hoses--gasket, somewhere--water pump. You can check the coolant for oil or coolant in the oil. The coolant leak could almost anywhere.
I did see a service bulletin for your vehicle. The fan shroud may rub a hole in radiator? If so, the radiator would have to be replaced. At the bottom of fan shroud you would use cushion tape in a couple of places. Use a small spacer washer at the top bolts. I can give you more info, if you think the fan shroud is the problem?

https://www.2carpros.com/articles/car-is-leaking-coolant

This can guide help us find the problem.

I will check and tell you

I added to coolant tank and I found water was falling downward somewhere from engine

It looks like you have a water pump or freeze plug problem, Here need to see up where the leak is coming from a little better, jack the car up and use a flashlight.

Here is a guide to help you

https://www.2carpros.com/articles/jack-up-and-lift-your-car-safely

and

https://www.2carpros.com/articles/radiator-pressure-test

Please let us know what happens and upload pictures of the problem.

Cheers, Ken

I show it to mechanic he told water pump is faulty. My question is that any way to repair without replacing it.thanks

You must replace it with a new one along with the timing belt. Here are some guides and diagrams (Below) of how the job is done on your car. The guide is a general one but still give you an idea on what to do.

https://www.2carpros.com/articles/water-pump-replacement

Here are the parts on Amazon water pump and timing belt with tensioner for $107.00 and its AC Delco which is the best brand.

https://www.amazon.com/gp/product/B004JB5BIM/ref=as_li_qf_sp_asin_il_tl?ie=UTF8&tag=2carprcom-20&camp=1789&creative=9325&linkCode=as2&creativeASIN=B004JB5BIM&linkId=6a952a6d4571304bfe7c328402932d08

Book gives it 2.7 hours but it might take a little longer. Set some time aside and have fun.

Please let us know what happens and upload pictures of the problem.

Cheers, Ken