Well I have been chasing a coolant leak on my '08 Sahara for a couple of years. Yep, that's right years. It would come and go, very strange indeed. At first I thought is was just the overflow tank with to much coolant, then maybe a bad radiator cap. However, it turned out to be the left side seam where the plastic tank and aluminum radiator meet. It is very small and hard to spot, it would leak just enough so you could smell it and sometimes leave the suspension parts coated in coolant. I have a new radiator coming in Wednesday so out with the old and in with the new. I really can't complain, the Jeep has 138+K on it and still running strong.