Coolant leak

Do you mean you need help in knowing what to look for? Or how to find the leak?

You need to include some details or observations so we know where to start. How fast does the coolant leak out? Do you just fill the reservoir once a month or does it take a gallon to drive across town? Does it run out on your foot as fast as you pour it in? Is there a puddle on the ground? If so, where and how big?

For really slow leaks there is a dye that can be added, then you search later with a black light. The dye will show up as a bright yellow stain that you can follow back to the source. Some leaks only occur when the cooling system is under pressure. You can use a pressure tester to make some of those leaks show up.