More cooling problems, now what?

[nomansland92]

Well i've been have problems with overheating and air pockets for awhile now so heres what ive done so far.

water pump
timing belt
thermostat
cross-over hose
fan clutch
rad cap
v belt
completely flushed the system
and just did the head gasket with oem one and torx head bolts

SO this is where im at now unlike before i now have way better heat and now my heat works when im at a stop unlike before. At stop the temp slowly rises however if i hold the rpm at like 1200 it drops right back down to half(I have no aux fan) to me it sounds like a flow problem becaosue reving it would just help it pump more.

But this is what has me all messed up, even after driving for half an hour the bottom of the rad is still completely cold so i guess that would be because the thermostat isn't opening but wouldn't if over heat very easily if it was stuck close? I can idle for like 5 min till it gets to like 3/4 temp.
I don't think it fott he best bleed becasue after i drained the whole system and filled it with screw open and i followed everyone's instructions but i didn't get much air out but everyday when i stop driving i open the screw and get a little more air out but only a little bit.

I just don't know what to do any more and im sick of dumping money in to the same problem so does any one have any suggestions on what to do now.
Any help would be really appreciated, Thanks Stevan

[NigelStu]

Have you confirmed that the thermostat is opening properly (at correct temp and fully)? Even new thermostats can have issues, like sticking part way. Put the thermostat and a thermometer in a pot of water - bring to a boil, check temp when it starts opening and when fully opened. If it opens late or not fully, try a different one.

Any way to check the there is flow through the entire radiator? Maybe something is causing a restriction in the lower half? You could try a reverse-flow flush with a garden hose, see if anything comes out.

[jlevie]

Have you check to see if the radiator is uniformly hot when idling long enough for the temperature to start to rise? You could have a partially plugged radiator.

Once the system is fully bled, the only way air can get into the system is from a head gasket leak. So the release of air on subsequent bleeds is evidence of a head gasket leak. When you had the head off did you have it checked for warp or cracks? If the head was warped, simply replacing the gasket won't work. A warped head requires surfacing.