Temperature and rpm problem micra k11

[Dimitrios Giakas]

when i drive with around 3000-3500 rpm and more the car's temperature goes up and when the car is idle the rpms go around 1800-2000 i have changed the thermostat before 2 days and i saw a great difference but today when i drove like i said with 3500 rpm the temperature and rpm went up but after 2-3 minutes they went normal something that didnt happened before the thermostat changing,and also the coolant from the expansion tank was dissapearing but for this the mechanic said that could be the torn hose that we also vhanged from the refrigerator, so i would like to ask what could be the problem,Sorry for my english i am from greece

 

[MattInARedMicra]

It sounds like you may have 2 issues occurring at the same time

The engine coolant sounds like there could be air in the system. To solve this park on a hill with the front of the car facing up hill, idle the car and allow the radiator fan to come on and off a few times, when the car has cooled down fully make sure there is enough coolant in the radiator cap and the expansion tank by filling them up, and then repeat a few times idling on the hill until all the air is forced out of the pipes into the expansion tank. If the coolant is leaking from the pipes you will know from looking under the car, but white smoke from the exhaust would indicate you are burning coolant which would be very bad. the AC system and the engine coolant system aren't connected though if this was the hose replaced, the AC should be from a pulley on the engine belt.

The rpm issue could be something called "limp mode" which would require diagnostics to figure out why, it could be the throttlebody, a blockage of the air filter or fuel filter, timing issues etc

1800-2000rpm is a high idle though the usual idle is somewhere between 700 and 1200 for this car but without knowing what has been changed previously I wouldn't say to turn the idle down using the idle control screw the best idea for what to do will come from diagnostics mode using the data connector under the steering wheel first and then go from there