When it comes to repairing coolant leaks, two popular products on the market are K-Seal ST5501 Multi-Purpose One Step Permanent Coolant Leak Repair and Permatex Radiator Stop Leak. Both of these radiator sealants are designed to fix leaks in a vehicle's cooling system, but they have some key differences.

K-Seal ST5501 is a one-step permanent repair solution that can fix leaks in the radiator, hoses, water pump, and other areas of the cooling system. It works by circulating through the system and forming a seal at the source of the leak. This product is easy to use, as it simply needs to be poured into the coolant reservoir and allowed to circulate through the system. K-Seal ST5501 is also compatible with all types of antifreeze and can be used in both gasoline and diesel engines.

Permatex Radiator Stop Leak, on the other hand, is a two-part solution that requires mixing before use. It is designed to fix leaks in the radiator, hoses, and other areas of the cooling system, but it may not be as effective at sealing larger leaks. Permatex Radiator Stop Leak works by forming a seal at the source of the leak, but it can take several hours or even overnight for the seal to form completely.

One key difference between these two radiator sealants is their permanence. K-Seal ST5501 is designed to provide a permanent fix, while Permatex Radiator Stop Leak may require reapplication over time. Additionally, K-Seal ST5501 is generally easier to use and requires less maintenance than Permatex Radiator Stop Leak.

In terms of compatibility, both products are suitable for use in most vehicles, but it's always important to check the manufacturer's recommendations before using any type of sealant. K-Seal ST5501 is compatible with all types of antifreeze and can be used in both gasoline and diesel engines, while Permatex Radiator Stop Leak may not be compatible with certain types of antifreeze or engines.

Overall, when it comes to choosing between K-Seal ST5501 and Permatex Radiator Stop Leak, the decision will depend on your specific needs and preferences. If you're looking for a quick and easy permanent fix, K-Seal ST5501 may be the better choice. However, if you're looking for a more affordable solution that can still provide effective results, Permatex Radiator Stop Leak may be worth considering.

It's also important to note that while these radiator sealants can be effective at fixing leaks, they should not be used as a permanent replacement for proper repairs. If you have a persistent or large leak, it's always best to consult with a professional mechanic to determine the best course of action.

In conclusion, both K-Seal ST5501 and Permatex Radiator Stop Leak are effective radiator sealants that can help fix leaks in a vehicle's cooling system. However, they have some key differences in terms of ease of use, permanence, and compatibility. By considering your specific needs and preferences, you can choose the best product for your situation and get back on the road with confidence.