I thought my truck was running cold. I thought it should be 90-100C right now its at like 75C. Nonetheless I flushed the heater core and voila heat Thanks

 

well, since i had the same problem, i went ahead and flushed mine too.
didn't notice any difference idling in the driveway, but we'll see how tomorrows drive to work goes. thanks for getting back to me david...

 

my heat was luge warm, so i flushed the heater core with a hose, then use prestone SUPER flush, follow the instructions, and it cleaned ALOT out of my system, i was running at 180, now i run at 192 (checked with my scanner as i drove) and my heat is BLAZING and its 10 degrees out right now

 

i flushed my heater core last night and drove the truck to work today. the heater is blowing noticeably warmer now, but still has a ways to go. i might try flushing the whole cooling system this weekend. it was at least worth doing. thanks for the info.

 

I had the same problem until today.First off I have only owned the truck for a day and it is cold here in Wisconsin too! The first think I did was to stare at the water neck outlet for a while and wonder why in the hell they made it so hard to get at,then I removed it pulled out the T-Stat and replaced with high quality 195 degree one using a gasket to seal the water neck outlet not silicone.To use a gasket properly I had to grind of
the compresion bumps on the outlet so it would sit flat and compress the gasket. Then I drained the radiator from the bottom hose and watched all this brownish rusty coolant come out as it was too cold to keep flushing I re connected the bottom hose.Now for what did the trick,I disconected
both hoses from the heater core and blew threw it with compresed air and watched some thin sludge like crap come out.I did this in both directions,re-assembled,added coolant and enjoyed heat !!!!!!!!!!!