Hello guys.I have changed the engine on my car,and after this the new engine overheats(when I puted the new engine I took all the parts off and cleaned and substituted all the things).So,it was overheating and overheating,and the ventilator didn't switch on,I tried it directly with a battery,and it worked,so the problem is not a ventilator.Today I went to drive on the highroad about 30-40 minutes,and after I got down from highroad the gauge sudently started to go up,when I accelerate a bit,the gauge goes down for a bit,but once I go slow it goes up again... I connected the ventilator to battery directly and went do drive inside of the city,but it still overheats.I took the thermostat off,and now driving without it,but the problem still persists... I also took the old thermo-sensor out,and put the 1 I had from my broken engine,and it still overheats.. I feel up the radiator with liquid(antifreeze),did everything again,like step by step,and the radiator and overfill tank were full,after driving for a while in the city it overheats again.It seems that there is no smoke coming out of exhaust,but yesterday when I was going with my friend to supermarket(he was behind me on the scooter),and I accelerated like to full(7,3 RPM)and so,he said there was black smoke coming out of exhaust.when the car is on idle,it throws some whater or maybe even antifreeze from exhaust.what would you advise ?could the problem be in "air inside of the cooling system"?? cause it just gets about 2,5-3 liters of antifreeze,maybe it creates the air bubbles inside the cooling system? I have this car for 1,5 months,and I spent already 1200 €,I'm very disappointed with it now,first the engine,then some messed screw,now this overheating problem... what could it be ? :( :confused: :( ,waiting for any advice,help,insight,Thanks in advance to helpful people

OK guys,half an hour ago I tried to take whole the bubbles out,and it worked,the cooling system cannot have air bubbles inside now... I've also noticed that my RPM gauge "dances" from 1000 RPM to 1500 RPM(yes,exactly those numbers) when the car starts to overheat.I've also noticed that the temperature gauge dances from half to almost up and vice-versa.I really don't know what's happening with my car... the liquid seems to not leaking,unless the car is overheated.I'm sooooooooooooooo much disappointed buying this car that you guys couldn't imagine... I heard all my life that honda it is like something much superior then other cars,like our well known german cars,Mercedes,BMW,AUDI... but it's far not that... all this electronic stuff... and the new ones... I'm not even going to say nothing,I see the same number of hondas as these new mercedes on the roads broken... mercedes isn't good now too... Well,let's get to point,what can you guys advice ?thanks in advance for answers if any

You could have a radiator which is plugged, due to corrosion or mineral buildup. Only use a 50/50 mixture of antifreeze and distilled water. Don't use tap, well, or softened water. Therefore, you may need a new radiator. Have this situation fixed before driving it again or you run the risk of warping the head and damaging the valves.

Hondas are good cars, but so are most others. It all comes down to good preventive maintenance.