I just did a head gasket maybe 3 weeks ago, new t-stat, flushed entire cooling system, added coolant/overflow reservoir, and had head checked.
Truck was running perfect nice and cool didn't budge off the little normal line and well today for no reason it jumped with in about a 1/8 of the temp gauge from the "H" Don't smell any coolant. But I pulled the Oil cap and it was slightly milky there wasn't any milky build up on the dip stick though

. Any ideas on why it is starting to get warm again? As far as I can tell it's not going threw any coolant.