Hi, I have no heat at idle but I do have heat when I'm on the highway with the rpms around 2000 or so i.ve changed my termastat.but that didn't help I tried burping the system by jacking up the front of the van and taking the cap off and letting it run.I didn't see any air escaping.it seems like I feel water going through the heater hoses.any help would be appreciated.thanks,greg

Trying bleeding the air out of the system again. Don't jack up the front end; leave it at ground level.

I've tried that already no luck thanks.