I have had a 1999 Chrysler LHS for three years with aprrox 100,000 mi, every winter when it is cold, it has a whistling sound in the engine. The sound sounds like it is coming out of the grill. If I let the car warm up for 20-30 minutes it stops, if I don't let it warm up that long, the whistling gets worse as I accelerate. Eventually it goes away when the car warms up. Do you have any idea what this problem is. My husband wants to get rid of it but I like the car and I hate to see it go. This problem doesn't happen during warm weather only in the winter. The colder it is out, the worse it sounds.