Hi, I have prado 96 model with 1KZ TE engine in it. When pull out the oil gauge tube or remove the oil cap there is significant blow by with smoke. The engine is running in excellent condition, no problem starting, excellent pick, no oil consumption. I went to local mechanic, he told me that engine is weak and needs overhauling. However, as per condition he recommended me to drive it for another 30,000 km before repairing. Can you guide me what should I do.