‘Stop Leak’: We do not recommend using stop leak UNLESS in an emergency situation.
If you discover a coolant leak, get it fixed ASAP. Don’t use stop leak as a solution because you are actually causing more damage. Stop leak will not only block the leak you have found, but it will block other cooling system components too. This will cost you more in the long run to replace extra blocked parts than just getting the initial leak rectified!
If however, you are in an emergency situation with no quick way of getting to a workshop, stop leak can be used for a very short period of time to get the vehicle to a workshop. Once at the nearest workshop, the stop leak must then be immediately flushed out of the cooling system.