# Weird heater issue **URL:** \ **Category:** Maintenance/Repairs\ **Tags:** forester, heating, brakes, subaru\ **Created:** [February 25, 2020, 12:50am UTC](https://community.cartalk.com/t/weird-heater-issue/159436 "2020-02-25T00:50:31Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![autoMATTic](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/automattic/32/19676_2.png) [@autoMATTic](https://community.cartalk.com/u/autoMATTic)\ **Post date:** [February 25, 2020, 12:50am UTC](https://community.cartalk.com/t/weird-heater-issue/159436/1 "2020-02-25T00:50:31Z")
Hey there! I have a 2004 Forester with a seemingly unique climate control problem: As I turn the temp dial from cold to hot, it’s gets to max temp after only a few click. To better explain, if the COLDEST setting is at 9 o’clock, then the HOTTEST setting should be 3 o’clock. In my case, the air is hot by 11, but it won’t get any hotter by 12, 1, etc. (thankfully). It’s as if the entire temp range has been compressed. Any ideas? Thanks! ---
**Author:** ![kurtwm1](https://avatars.discourse-cdn.com/v4/letter/k/13edae/32.png) [@kurtwm1](https://community.cartalk.com/u/kurtwm1)\ **Post date:** [February 25, 2020, 5:57pm UTC](https://community.cartalk.com/t/weird-heater-issue/159436/2 "2020-02-25T17:57:48Z")
That’s not unique to your car. The heater core can’t produce more heat than the temperature of the engine/water. If the max is reached at 9 o’clock than that’s it. The other possibility is a somewhat clogged heater core. An inexpensive back flush could improve and raise the temperature. Search youtube, lots of videos on that topic. ---
**Author:** ![autoMATTic](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/automattic/32/19676_2.png) [@autoMATTic](https://community.cartalk.com/u/autoMATTic)\ **Post date:** [February 25, 2020, 6:15pm UTC](https://community.cartalk.com/t/weird-heater-issue/159436/3 "2020-02-25T18:15:48Z")
Thanks for the reply! What makes this more interesting is that at 11 o’clock, when my heater is it’s hottest, it’s as if we’re actually at it’s MAX setting. The heater gets plenty hot, just too soon. In terms of radial degrees (NOT temp), the entire 180° range of the dial is compressed to maybe 60°. When at it’s coldest setting, everything works as it should, a few clicks up and it gets uncomfortably warm. A few more clicks and it’s maxed out and perfect for a frosty morning. It won’t get hotter after that, but I wouldn’t want it to anyway. ---
**Author:** ![Tester](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/tester/32/15976_2.png) [@Tester](https://community.cartalk.com/u/Tester)\ **Post date:** [February 25, 2020, 6:28pm UTC](https://community.cartalk.com/t/weird-heater-issue/159436/4 "2020-02-25T18:28:42Z")
> [@kurtwm1](#): > > The heater core can’t produce more heat than the temperature of the engine/water. Explain that please? Tester ---
**Author:** ![kurtwm1](https://avatars.discourse-cdn.com/v4/letter/k/13edae/32.png) [@kurtwm1](https://community.cartalk.com/u/kurtwm1)\ **Post date:** [February 25, 2020, 6:49pm UTC](https://community.cartalk.com/t/weird-heater-issue/159436/5 "2020-02-25T18:49:07Z")
Heater cores are not designed to raise the temperature to not more than around 130 degrees. If the water temperature is ~160-170 at the core it won’t be raised. Give or take a few degrees. ---
**Author:** ![Tester](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/tester/32/15976_2.png) [@Tester](https://community.cartalk.com/u/Tester)\ **Post date:** [February 25, 2020, 7:12pm UTC](https://community.cartalk.com/t/weird-heater-issue/159436/6 "2020-02-25T19:12:51Z")
> **[What is a heater core? — Ricks Free Auto Repair Advice](https://ricksfreeautorepairadvice.com/what-is-a-heater-core/)** > > A heater core is a small radiator located in the cabin of your vehicle. But poor coolant maintenance can clog the core and cause low heat or no heat in your car. Tester ---
**Author:** ![kurtwm1](https://avatars.discourse-cdn.com/v4/letter/k/13edae/32.png) [@kurtwm1](https://community.cartalk.com/u/kurtwm1)\ **Post date:** [February 25, 2020, 7:15pm UTC](https://community.cartalk.com/t/weird-heater-issue/159436/7 "2020-02-25T19:15:55Z")
> [@kurtwm1](#): > > designed to raise the temperature The end result is not much different from what I stated, except I should have said “regulated” instead of “raised”, poor choice of words ---
**Author:** ![Tester](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/tester/32/15976_2.png) [@Tester](https://community.cartalk.com/u/Tester)\ **Post date:** [February 25, 2020, 7:26pm UTC](https://community.cartalk.com/t/weird-heater-issue/159436/8 "2020-02-25T19:26:06Z")
The vent control module may be sending an erroneous signal to the blend door actuator causing the blend door to open to soon. Tester ---
**Author:** ![shanonia](https://avatars.discourse-cdn.com/v4/letter/s/9de053/32.png) [@shanonia](https://community.cartalk.com/u/shanonia)\ **Post date:** [February 25, 2020, 8:39pm UTC](https://community.cartalk.com/t/weird-heater-issue/159436/9 "2020-02-25T20:39:31Z")
Any time there’s a cooling system anomaly (that includes this situation) I think of air trapped in the cooling system and a possible head gasket leak behind it all - especially with Subarus.