When I bought my DD a 2000 it had the heater core bypassed so I checked and the HC was ok and bought some hoses and hooked them up. I put a smaller diameter hose inside the heater hose on the inlet side to restrict the flow. I have done this on most of my cars because high RPM pressure I have seen split the heater cores. Fords are famous for it, nothing like a 7K shift in my Mustang and the windshield fogs up and my feet get a splashing of boiling water.

Ever since the temperature gauge does not rise smoothly? I tends to stay cold too long and then when it warms up it sometimes comes back to cold side after 30 minutes of driving? Also the heat is not very good.

Do you guys use a restrictor in yours? Should I remove it? I have already replaced the temperature sensor so that is not the problem.

 

Seriously, sustained high RPMs can blow out a heater core? No wonder doing all the drifting I used to do played hell on heater cores, as I replaced 2 of them. By the 3rd one, I got smart and removed all the hard-lines and replaced them with rubber hose and changed it out in 30 minutes.

 

Air needing to be burped from the head will cause the problems you mentioned.

 

Any suggestions how? I have tried nose facing trees and all. Remember this has been happening for the last 1000 miles over the last three weeks or so, I figured it would have worked it self out???

 

put the front of the car in the air
take the rad cap off
let the car idle up to temp
when the t-stat opens (or before) squeeze the soft lines and the air will come out