Myself and the mech at a shop i dropped my car off with yesterday are completely puzzled and if I could get some ideas, that would be fantastic...

Heres the story...
While driving from nc to philly, one of the small hoses on my radiator some how popped off (the small one at the top). Being that it was raining and how my arm was positioned so it was infront of the temp gauge, i never noticed i was overheating (the car has 130k mi on it and never been to the shop yet for anything other than routine maintenance so i never even think to check the temp). Anywho, i stopped to go to the bathroom and only then noticed the steam shooting out from under the hood. I was able to get the hose clamped back on, refill with some water and antifreeze, and got back on my way..

Heres where it gets interesting... When at highway speeds, the car runs perfectly normal temperature, with the needle a few ticks below halfway up the temp gauge. When i slow to 30ish or below, the temp goes back up. speeding back up to highway speeds cools the engine back to normal. The thermostat, radiator, and fans have all been checked and are functioning normally. When the car was at the shop yesterday, they had it sitting in the hot sun and running for 20 minutes and couldnt get the thing to overheat, checking it both with the temp gauge on the cluster, as well as a IR thermometer. The shop called last night to get permission to take my car out on the highway today (first time a shop has ever done that, much appreciated!) so we will see if they can recreate the problem.

Anywho, does anyone have any ideas at all what could be going on? I am completely puzzled.

Thanks!

 

btw, to add, this is on a 01 ex sedan, 5spd

 

bump

 

Air inside the block maybe?

 

i suppose anything is possible. this might be the first time ever that i just take it to the dealership. yea its expensive, but its cheaper than needing a tow truck half way home in a few weeks when im driving 400 miles