Most enviromentalist will kill me for this, but unless you have a drivablity problem, the coolant leak isn't the end of the world. Just a annoyance and an enviromental hazzard. You can still drive the bus. You'll just need to keep an eye on the coolant level. <br><br>I drove mine for for about a year with a coolant leak. I used more coolant in the cold weather and less in the summer. I averaged about 1/2 gallon a week. I drove about 200 miles a week. Every few weeks, I used to put in a stop leak additive called Bars-leak. It would slow the leak up quite a bit. <br><br>Bob Donalds will tell you that any waterboxer engine over 100K miles should be replaced. I think that it should be replaced at about 150 or more. Mine had 160K when the leak appeared and I put another 13K or so before I replaced the engine. So if you have anything under say 120K my advice would be to save your money for a new set of heads and gaskets. Good luck.