Hey,anybody else have problems with getting heat out of the 6.5L G-Van chassis? We have a bunch of mini-buses biult on the G-van cutaway and several of them don't make any heat in the bus when the temperature is below about 40degF. We have the same problem with both the Thomas Minotour and the Bluebird MicroBird.We've tried new thermostats and double checked the plumbing on the supply hoses but there still isn't a lot of heat. I've got a bunch of very cold very angry drivers.