I have an 09 Tahoe and i had a leaking radiator (fluid always dry in reservoir) so i had it replaced. The radiator that i received had 2 extra ports that arent used. After this change was done i noticed that my heat took long to get hot. With a hot system i can remove the cap with little no no pressure in the system. Also my oil pressure gauge was maxed out at 80 yesterday and now its at 0 today but no engine light is on. Any assistance would be grateful. It acts like it wants to overheat when idle but when moving it drives normal and actually never overheats.

 

Welcome to the forum. Moving your post to the Tahoe section of the forum where you will get more views. One thing you should check is your thermostat.