I have a 2002 Nissan Altima with 107,000 miles. It has no heat at Idle, other than that it runs great. I have tried to bleed the system by jacking up the front end, the system has been flushed, thermostats replaced with the same result. When trying to get the air out of the system, you can get heat at idle initially, but as soon as the car is driven 5 miles or more, no heat at idle. I feel there must be something else wrong with the car and searching for someone's knowledge and advise. Thank You.