I noticed my coolant was low the other day. I also noticed that wonderful antifreeze smell from the exhaust when unloading groceries today. Now I've got to find the leak, but there is no coolant leaking externally on the engine. Has anyone had to deal with internal engine coolant leaks? Is there some sort of commonality (like 3.1/3.4 GM engine intake gaskets)? I'm going to dig in this weekend but would like to know if there is a common failure point on these engines. Thanks!