Cadillac CTS-V - Coolant change

Just changed the fluid and the thermo and now the hose that comes out of the thermo housing collapses overnight. Once I open the tank its fine. Also after driving its fine. Are there any tricks to get the remaining air out ?

Let it run with the cap off

Let it run with the cap off

I did that in my driveway. Should I go for a short drive ?

Is there a crossover in the TB?

Is there a crossover in the TB?

Yes, I have not made any changes except the thermo.

Your cooling system is not filled all the way. Let it run and get hot with the coolant reservoir cap off, then hold the RPM's to about 2000-2500 RPM and fill it all the way to the top. The only fast way to completely fill the system is to have the waterpump drawing from the reservoir with the thermostat open. Do not let the engine idle until you tighten the cap or all the coolant will surge back out.

Once you tighten the cap and return to idle, the cooling system should be pressurized as normal. Grab the upper rad hose and make sure it has pressure on it. No pressurized cooling system = underfilled.

Your cooling system is not filled all the way. Let it run and get hot with the coolant reservoir cap off, then hold the RPM's to about 2000-2500 RPM and fill it all the way to the top. The only fast way to completely fill the system is to have the waterpump drawing from the reservoir with the thermostat open. Do not let the engine idle until you tighten the cap or all the coolant will surge back out.

Once you tighten the cap and return to idle, the cooling system should be pressurized as normal. Grab the upper rad hose and make sure it has pressure on it. No pressurized cooling system = underfilled.

Sounds good, I will try that.
Thanks