# Heater - 2000 GMC Sierra Truck

**URL:** <https://community.cartalk.com/t/heater-2000-gmc-sierra-truck/37611>\
**Category:** Maintenance/Repairs\
**Tags:** heating, gmc, 1500\
**Created:** [October 5, 2009, 4:08am UTC](https://community.cartalk.com/t/heater-2000-gmc-sierra-truck/37611 "2009-10-05T04:08:17Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Robertsundberg](https://avatars.discourse-cdn.com/v4/letter/r/a9adbd/32.png) [@Robertsundberg](https://community.cartalk.com/u/Robertsundberg)\
**Post date:** [October 5, 2009, 4:08am UTC](https://community.cartalk.com/t/heater-2000-gmc-sierra-truck/37611/1 "2009-10-05T04:08:17Z")

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The heater in my 2000 GMC Sierra truck (non Air Conditioned) is not getting very hot. Anti Freeze has never been changed / flushed; but the reservoir is full. Does this sound like a an issue with my coolant and the system needing flushing or a problem with the heater controls. The temperature gauge shows that the engine is heating up normally. When I turn the heater temperature control on the dashboard, it rotates like it has always done in the past - but it does not heat up like it used to - the air coming out fromt he heater only gets slightly warm. I live in Alaska and it is getting cold outside and I need a good heater.  
  
 Thank you

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**Author:** ![circuitsmith](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/circuitsmith/32/40376_2.png) [@circuitsmith](https://community.cartalk.com/u/circuitsmith)\
**Post date:** [October 5, 2009, 5:17pm UTC](https://community.cartalk.com/t/heater-2000-gmc-sierra-truck/37611/2 "2009-10-05T17:17:33Z")

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Your thermostat could be sticking open.  
It’s overdue to be replaced, IMHO.  
I change mine every 4 years.  
So change your coolant and thermostat.  
Might fix the problem and needs to be done anyway…  
This will also save you gas.