About the valve seals, yes they were replaced during overhauling.
Before the car has been scheduled for ovehauling, these are the signs:
1. When rev at higher acceleration, black smoke is coming from the exhaust and significant reduced in engine oil.
2. During idle, white-blue smoke was also there.
Right after overhauling and break-in at idle speed, no black smoke has been observed. But when accelerated, heavy cloud black smoke is there to the point that excess gas also mixed with engine oil leading to the busted spark plugs (heavily carbonized). Replaced the exhaust O2 sensor and the spark plugs. Heavy smoke has gone. What remains is little black smoke coming out from the tail pipe when highly accelerated, but no signs of failure detected from scanner.
Wednesday, November 12th, 2014 AT 2:59 AM