Maybe you blew the headgasket?

 

Ok another update. Just for giggle I took the coolant cap of my wifes v70 put it on my 850r and it does not seem to be overheating?????

 

Maybe the cap is bad. Not holding the proper pressure will play havoc with the system.

 

You probably have your answer by now. If not, the signs you are describing fit a blown head gasket. You dont have to have fluids pass between the oil and cooling. The compression of the engine getting past a gasket into the coolant system will pressurize the system.

 

So what was the conclusion i have done everything upuntil here. a cap is the answer?
i replaced the top heater hose and coupling. started her up and she was doing the boiling out the reserve. lots of pressure from the top hose. could a temp sensor make this motor overheat? im clueless and about to pull the head off

 

Its been over a year since it happend and the fix was the cap, always try the cheapest way first, but also the water pump was going bad. Hopefuly this will fix your problem