I have had my 01 for 5 months now and have had the antifreeze topped off 2 times and is low again. I have looked for leaks and are none. I have told the Dealer adout a tick- knock sound and all they say is its a diesel and makes that sound. Do I have an internal leak. And is the ticking a problem not related or is related. This is B. S. to have to ad antifreeze every 2 to 3 weeks. I dont use alot and only have about 4500 miles on and has been no hard driving at all. Can anyone help as to whats going on. I sure dont want to blow up the engine. I hate the idea that the engine has a, Internal antifreeze leak and or is eating antifreeze. That isnt a good thing on it and I thought I heard someone say antifreeze trashes the inside combustion parts. Help!