Heater and Temp Guage issues in 99 Venture

[DR_NO]

We have a 99 Venture van that we are now having problems with. The temperature guage will act erratically. when you start the van it will sweep way up, then back down, and when accelerating, it will sweep up like a tach, then back down. the coolant levels are fine, however i was reading a thread here that is concerned with the DEX-COOL, and that is what is in it.

It was flushed and filled a couple years ago. the secondary issue is that the heater is not working properly. what used to take minutes to heat up, now takes 20 minutes or more, especially when running around town. As my wife drives this vehicle, the heater is a MAJOR issue heading into winter.

Any thoughts on this? sounds like a potential thermostat/heater core issue, but I need some guidance.

Thanks!

[cdru]

Could be a fault coolant temp sensor or poor connection. It also could also be air bubbles in the line.