Heater on=big temp change

[BlackDynamite]

Well it just started getting cold here, and i started to use the heater(note the last time i used my heater it blew out the freeze plugs....Because the machine shoppe put in too small of size)

Well it was idleing the other night at Walmart, while i was talking to friends, and then noticed that it went from the halfway mark on the temp to about 4/5s....I was like WOAH!....so i turned it off, i turned off my heater and set it back down to 65....then turned off the fan....i let it cool and drove it back to the house, then it dropped really low and would fluctuate between 1/4 to 1/2....like constantly, then it blew white smoke out when i revved it once but then it stopped...i was like WTF!?!? BHG?(geddy metal head gasket)

So i let it sit over night and checked the radiator, THE WATER WAS FREAKIN BROWN AND GUNKY.....it had NEVER been like that, so i unscrewed the drain plug and got all of that brown stuff out....flushed it etc....put the plug back in and filled it up with 50/50 it never turned brown again....what the hell happened?

 

[cuel]

If I'm not mistaken, there's a valve that closes the heater core off from the cooling system when its not in use. Brown crud was probably stuck in the heater core, or was from the coolant/water sitting stagnant in the heater core while you weren't using it. Did you turn the heater on when you filled the cooling system after the f.p. incident?

 

[BlackDynamite]

no......

 

[jdub]

And some of the gunk may have clogged your thermostat...I'd pull it to make sure the stat and water neck it's attached to is clear.

 

[cuel]

^^ What he said. Fill the radiator with correct coolant/water mix, then start the car and turn the heater on full. Should pull water through the heater core, and chase the air out. Just run it for a minute or 2, it won't take long. Refill the radiator and reservoir, and you should be good to go.