My heat wasn't blowing to its full potential in this 20-30 degree weather. It would blow warm at level 1, then would get cooler as you turned up the fan. Did a little research on here to see how others flushed their heater cores out to see if theres anything else I could do to get my heat back. I've flushed my core before, but with only water. This time I flushed it out back and forth then I poured in a bottle of CLR and let it fester around in there for like 5 minutes. Then flushed it again with plenty of water and then finally filled it with coolant to make up for any loss. Started it up and I have so much heat now I have to turn it down. I forgot how hot this thing can get, man am I glad I flushed it out. I had my intake manifold gasket replaced 2 months ago so I figured some junk got stuck in there when they were doing that. If anyone runs into a similar problem I suggest doing this flush.

 

Some idiot before me poured leak seal in the cooling system and this crap is the worst. It clogged the heater core.
I flushed out the whole system and the first few seconds there was just brown and black **** coming out. You can imagine how the core must have been clogged. Now it´s working fine again.