please i reside in Nigeria, my nissan maxima 2001 is experiencing serious heat underneath my engine causing leakage under my oil reserve tank, i topped oil and changed the oil seal since the car engine oil was short. My cooling fan is in good working condition and i have completely remove the thermostat.
After doing that, i still experience the heat from the engine from the driver's seat. my temperature gauge is normal but when i observe this heat i always notice that the engine will find it hard to move even if i rev the engine, but if i allow the engine to get cold a little it will start moving normal until it get hot again. Could this be exhaust problem?
What can be the cause of this, because i cant travel for more than 12km without experiencing this.

 

sounds like you may have a clogged cat. next time this happens look under the car from the driver's side door to see if the precat is glowing red.