Problem With Rebuilt Engine
 

After the first slowly 1000klm,I change the oil and the coolant flush. the radiator loose coolant and I change it.After I saw the add light come on and I put again flush but I look and at the oil cap.1. Coolent Overflow in the Tank2.oil cap has water.3.engine start with one rotor and after few time come them in right.4.when I open the radiator cap spits at me flush ,air/bubbles .5.after half hour no coolant flush in the upper hoses.5.temperature is down.6.smoke only at first two second .7.no strong smell. what happen????????BAD REBUILD?

Oil cap has water, or condensation (water droplets)?

Is there coolant in the oil? You can see this on the oil dipstick, the oil will be milky chocolate in color...In that case, yes, bad rebuild...

water droplets is at the time on the oil cap and the oil dipstick is clean (the oil is new 20klm)

I feel for you . . .

You have classic symtoms of an internal coolant seal leak.

The seal between combustion gasses & water jacket is a rubber O-ring in a groove all the way around the aluminum housing.
If it leaks you get coolant in the combustion chamber and overheating symptoms, just like a blown head gasket in a piston engine.