Strange overheating - urgent (holiday)

[Silenus]

First of all sorry for eventual bad english and for another overheating prob. but couldn't find a simular one...

Have a E34 '88 6cyl. and since the "filler screw" on the radiator came loose while driving (probably not tightly screwed enough I got eye on a diff. problem.
Refilled it and did the bleeding thing.
When driving T° stays kinda low (about a bit lower then 1/2 mark),
even after drivin' about an hour but when idle the T° goes up untill the red (after about an half hour)
and only then the cooling starts to blow a lot of air. Imo this ain't normal, or am I wrong ?
I guess it should start blowing more when the marks on 1/2 or between this and the 3/4 mark at least,
though the guy I bought it from, a non-certified BMW dealer, says it shouldn't be a prob..
He checked if everything worked; did the blleding thing, thermostat, fan clutch, waterpump, no strange smoke and stuff...
Problem is, after 2 days I have to get on a 1.400 km (=900miles) holiday drive with possible traffic jams
(though I'll ride during the night, so less heat and stuff).
Normally in this condition it won't go into the red (or a slight bit 'till the full cooler activates and sets it back at 1/2 mark)
but that ain't a stressfree way of traveling imo.

Thanks for reading and any comments/hints/help

[e39dream]

if it's still filling with air you have not bled the system properly. You need to get it hot (halfway on guage, not in red), crack vent screw to relieve pressure, tighten. stop motor, allow to cool over night. refill coolant as neccessary in the morning, repeat until no more air comes out and coolant level is full cold.

[LJSE34]

search for "bleeding m20" threads, it can be a nightmare

[Silenus]

Didn't knew it would take that much bleeding sessions...
and that it could cause such late cooler starts.
Gonna give it a little more bleeding then...though I think the bleeding thing was done enough
'cause the heatingsvents blew hot air and all...
Thanks everybody for reading and the quick answering

[forsaken]

it doesn't matter if the vents blow hot.. they will blow hot with some air in the system.

When you get it warm, you need to get all the air pressure out... when you bleed it, it should look like a tea kettle that is blowing steam. That is a good sign as this is getting rid of the air (along with a little water vapor.) When you have a full stream of coolant coming out with no bubbles, then the system has been blead. Then keep running her, and do it again, and again...

good luck.

[Silenus]

I hope it's not a headgasket problem...
Can this be? Even if there is no white smoke coming out of the exhaust?
(My first heating problem occured when the coolant reservoir cap came loose
and therefor had coolant loss...)
Thanks again