About 3 days ago I was turning onto my street and my 970 started to overheat. When I parked in the driveway I saw smoke coming from under the hood. Upon inspection and removing the manifold to see in the hot v I found the plastic coolant vent hose broken in pieces , probably the original. I ordered new and installed and reassembled everything today . Added coolant , turned the car on and let it idle until it got to temp. After I thought it was safe to test drive I got about 1,000 feet(end of my street) and temp started to rise quickly . Brought it home and checked/topped off coolant . It continued to overheat. Now I’m at a loss , could it be water pump ? Thermostat? What could’ve caused coolant vent line to burst other than simply its age . Sorry for the long story I just want to give the full scope .

 

You need a thorough diagnosis.

1. Are you losing coolant? Where? Why?

2. Does the cooling system hold pressure? Measure it.

Let the car idle for 30 minutes in your driveway. What happens?

 

Well I figured this one out with about 20 mins of YouTube videos. I was panicking and started watching videos on water pump replacement when I saw one of the mechanics open up an air pressure relief. I went back to the garage removed the cover around the coolant reservoir to find this valve . Opened it up and topped off coolant (it was about 3/4 of a gallon low) fired it back up let it idle heat on full blast then I drove on some back roads like a maniac for about 20 mins. Good to go !! No leaks and temp is stable

 

Appears you had a massive air block in the system... good for you to use the pressure relief valve. Keep an eye on it, but appears you have purged the system of air.