Stop Leak Products: Do They Work?

I tested 4 on my own vehicles. Two slowed the leak, two did nothing, none fixed it.

The bottle is $12. The repair estimate is $1,400. That is why these products are tempting, and why the internet is full of confident opinions from people who never ran one.

I tested 4 on my own vehicles. Every result is in here, including the ones that cost me money.

- How to find the leak first: fluid color chart, tracing, UV dye

- Oil, coolant, rear main seal, power steering, transmission

- A 4-step decision framework: severity, cost, timeline, results

- Every product rated for heater core clog risk

- When to try the bottle, and when to walk away

Instant PDF download. 30-day refund.