You know I have to say I've used Bars Leaks a few times and it worked great. My wife developed a slight leak between the block and the head of her 4.0L 6cyl Jeep Grand Cherokee around 100K miles and I used the Bars Leak silver seal and it held up until 178K when we sold the Jeep. The leak was slightly dripping down on the outside of the block. Have to say no complaints here with Bars Leak products. Again not the proper way to handle the situation but did not have the money at the time to do a complete head job.