I replaced my thermostat (motorad) about 6 weeks ago and learned about bleeding the system. Everything has been good until yesterday when I returned home from a 100 mile trip. No problems temps were steady at around 195 like usual. Took another short trip no problems. Washed the car. Turned the car on went inside to tell the lady I was going out again (5 mins). I get back and the temp is 221. I tried to bleed it with my no spill funnel and it boiled over. Today I notice that the hose under the stat is cool and I let the vehicle get up to 212. So i'm wondering if it could be anything else besides the stat. I've already ordered a new genuine dark grey one. Anything else to look at? Thanks in advance.

 

First, never try to bleed the cooling system if it is not stone cold.

Other than the temp being at 221°F what was the condition of the cooling system? Was the reservoir low? Was it empty? Was it full? What caused you to think that bleeding the system would be helpful?

 

My thoughts practice also.

That brand is prone to failures from reading here and there.
......

 

The car over heating was the #1 reason for me to try bleeding it since it worked before. The reservoir was low.

also the oil seems the same and the exhaust seems normal
I have a block tester coming but hopefully not needed.
I might have heard a few bubble earlier also.

 

The purpose of bleeding the system is to remove air from it. It needs to be done at the conclusion of a drain and refill, but otherwise not unless you hear the infamous "waterfall" sound from behind the dash indicating air in the heater core.

Overheating and a drained reservoir simply indicates a leak somewhere in the system. Can you see coolant on the ground or around the engine? Have you checked for evidence of coolant underneath the throttlebody heater, a well-known failure point? Is there any evidence of coolant underneath the reservoir?

If you can't spot the source of the leak you can get a loaner pressure tester from an auto parts store, pump it up to 15 pounds and see where the coolant comes out.

Diagnose, diagnose, diagnose.