I had a severe coolant leak through the timing chain cover on a 2006 Ford Ranger and it ran and held. Make sure your radiator is completely drained before adding this stuff, then pour coolant over it and make sure your coolant reservoir is also level while the coolant heater runs for about 30 minutes and that's it . should be good! It's an amazing thing, and I'm a woman, and I did it because it's bloody hard to throw away $1,300 on repairs right now.