I have a BMW 530i 2007, the engine gets hot up o 115 degree of celcius, it actually fluctuate between 95 to 115(which is a little bit higher than normal specially when the outside temperature is 5 c)
I checked the water pump, it was working steady with no strange noise, and there was no air in the system(bleeded). I don't know if the water pressure was normal, but its like a human male is peeing with high speed in water reservoir😂
I replaced my burnt headgasket last year, and after getting it fixed, I still see green sludge under the water reservoir cap.it seems that the mechanic that replaced headgasket forgot or was lazy to flush the cooling liquid.
Now that the engine gets hot, I am guessing the oily sludges and residuals are blocking the liquid current somewhere in coolant system. Could it be the case? How much oily sludge in coolant system could prevent circulation of water?
The ventilated air is cold sometimes, when it is expected to be hot, for example while the engine is 90 degree of celcius.
I also think that the thermostat is failing cause the radiator fan start to spin with high speed at the morning while the engine is cold and is just started, though the fan does not continue with high speed and it keeps switching between low and high speeds.
With above comprehension, what is(are) the problem(s) with my car?