Hello all new here to TItan forums. I've got a 2008 Titan 2WD Ext cab with the 5.6 FFV and about 160k on the miles. My engine temp had been spiking in heat and wouldn't go down. Replaced, thermostat (didn't have one), and both cooling system caps. Did a drain and flush using Blue Devil until ran clear. I bought 4 gal of the Valvoline 50/50 Zertex to refill. I was able to get 2 gals in even after squeezing hoses to vent any excess air. Can't fit anymore in without getting overflow. Would appreciate any thoughts the group might have. Thanks!