1999 Saab 9-5 4 cylinder overheating issue

VIN: Ys3ef48e8x3071072

Recently my upper radiator hose came off spilling coolant. The plastic neck that the hose connects to has lost it's lip to the point where the hose sometimes has difficulty staying on. I replaced the standard clamp with worm gear clamp and the hose has not come off since. The car was filled with coolant and bled to the best of my ability, though I understand the system to be self-bleeding. Now the car overheats shortly after driving. When idle it seems to be able to maintain temperature (horizontal needle.)

The thermostat seems to open as the upper raidator hose is filled with coolant. The air from the AC blows very hot; initially after filling with coolant the air would get hot then "normal" temperature (assumed to be because of air pocket in the heater core.)

Coolant used was dexcool g-05.

Any guidance or ideas for moving forward with this are appreciated. Also if anyone has a service manual I would be in your debt!

Thanks

I've noticed that if I drive the car around with the heat on full blast the car does NOT overheat. My current plan is to take the thermostat out and do an oil change (it's about time for one) and see if that fixes the issue. Will keep you all updated FWIW.

Bump for info?

Did an oil change, no change in behavior.

I topped off my coolant (while cold) with some water, as not much was missing, and I have noticed the fluids do NOT seem to be mixing. It was my understanding that the coolant reservoir is part of the coolant system, so, shouldn't it be mixed?

Coolant in the reservoir doesn't mix. Maybe on an atomic level, some molecules do move but not much. If coolant expands and flows into the reservoir, some mixing will happen but almost none.

The same is with brake fluid. Otherwise, one could change brake fluid simply by sucking the reservoir and putting new fluid in.