What i do when my car is mixing oil and water

This article says it is from the oil cooler heat exchanger.

http://www.teamfiat.com/threads/engine-oil-mixed-with-coolant.15125/

https://www.google.com/search?q=Tata+indica+vista+oil+mixing+with+coolant

Oil mixing with water is mainly due to head gasket that has blown between ports.

Check oil by draining. Trans tank on radiator bottom may be oily slick you see if oil pan drained clean. Then trans is probably contaminated with antifreeze and that's what is mixing.

Crack in head passages could link oil and water, if you verify antifreeze and oil mixed in oil pan.

Oil cooler on this engine is inside the engine under the intake manifold. If it goes bad water and oil mix.

Replace the head gaskets. It would have passed the smog test, because oil and water are not getting in to the cylinders.

Yes there is another way, someone can be messing with your head and pouring water in your oil cap. Do have water in your oil or oil in your water or both? A product called sea foam does a miraculous job at getting water out of oil. As far as keeping it from happening further, the cheap way of course is "bar's stop leak" but man can this stuff do a number on clogging your heater core, even if they say it doesn't, it can happen.

you have a cracked head or bad head gasket.

If it was not overheated real bad the intake gaskets are a big problem on those engines

The oil will appear 'milky' if water mixes with it.

yes it can mix, also check the timing cover for rubs from the timing chain. this is the common problem with 22r. many mechanics will tell you its the block but they are just trying to make money.