I have a collant leak somewhere it smokes when engine isn't running. The temperature Gauge inside the vehicle stays at about 85 Celsius once warmed up,it hasn't gone above 90 though. Is it a hose or should I use radiator repair fluid? I was told I needed a water pump then someone else said it could be the radiator. It was making a knocking sound earlier today.I've been keeping up with the collant & radiator warning light isn't on

 

Have a repair shop pressure test the cooling system. In most cases an external leak can be found that way.

It could be as simple as a loose hose clamp.

Cheers
DD