05 1.8l no heat

I am working on a 2005 Nissan Sentra 1.8L for a buddy, there car has absolutely no heat coming from the vent but it overheats, he replaced the t-stat and still no go, took it to a shop and they said probably a bad head gasket, so i just got done replacing the head gasket and water pump and still no heat. both heater hoses are cold, lower radiator hose is cold, upper hose is hot. I am at a loss, I tried bleeding the system many many many times to no avail.

I seen there have been quite a few issua with these cars and this problen but I still haven't came across a fix for it.

Any Ideas?

so no one has any ideas to what is causing this problem? theres has been quite a few of these exact issues but no resolution.

sounds like an obstruction in the lower hose or possibly on the radiator since you already replaced the w/p