figured id add mine in here. mine is similar except it goes past the L almost towards the HOT marking.. then goes back down. and my coolant seems to be disapearing also. im thinking it was a failed attempt at burmping? im not sure where the weep hole is but the water pump is about the cleanest part on the engine cause its new. so i didnt see anything dripping
rad is new, hoses are new, water pump is new. old owner had it done.
i flushed it yesterday and put in a new 190* motorcraft thermostat. havent had enough driving time to see if it resumes yet. i burned it til i only had a few tiny bubbles this time, using a large funnel.
and when i say flush, i mean run the truck using a flush kit in the heater hose. take the heater hoses off and spray down each hose. spray down into the heater core directly. spray directly into the thermostat hole on the intake, with it removed. all of that til the water was completely clear
one thing tho. my fan is cracked to holy hell. would that cause every bit of the problem?