Just pick up a coolant dye kit, put it in, run it for a few days, and then use the little flashlight to find the leak. If it is an external leak you'll find it.
No, I certainly don't. I friend bought a new Ford pickup about 4-5 years ago and it (under warranty) developed a hairline crack in the upper inlet where the radiator hose connects. He had to take it back several times before the "mechanics" at the dealership figured it out. It only leaked coolant when the engine was hot and run at highway speeds. If the "mechanics" would have actually grabbed the upper radiator hose and wiggled it they would have found the leak. Instead it took several return trips to the dealership because of the coolant smell; the owner finally found the leak simply by poking around himself and was able to point it out to the "mechanics" who couldn't find it.
Originally Posted By: turtlevette
If it was something simple like a cap, reservoir, or hose don't you think the mechanic would have found it?
Agreed. Find the cause of the leak first, then decide how to fix it correctly.
Originally Posted By: KB2008X
Adding anything to a cooling system, like a "car-repair-in-a-bottle" is a really bad idea, especially at this point. It is way too early to add any crud to your cooling system. Adding that stuff should be a desperate, last chance, Hail Mary pass, kind of a deal. Diagnose the problem correctly first.