A couple of weeks ago I had my truck at the dealer for a warranty issue. While there the service writer tells me that his tech is sure that I have an intake manifold leak and that they want to pressure test it but i'd have to agree because if there is no leak warranty won't pay for the test. I agreed and of course there is no leak. Since I've gotten it back there's been an intermitent anti-freeze smell. I can't find any leaks. Any thoughts on where the smell maybe coming from.