Nissan Repair: Engine sludge, oil sludge, kerosene oil

Question
What is the best thing to do if your car have engine sludge?

Answer
Akira,

Use a quart of engine flush.  It is kind of like kerosene oil and dilutes your oil in the engine.  You add a quart and drive it for the time indicated on the label and then change the oil.  It will take a couple of times to get things cleaned up.  Also, if you have the money you can use Mobil 1 5W30 for a couple of oil changes to get things cleaned up too.  Now, you need to make sure the thermostat is working because a cold engine will cause oil sludge.