The yellow light appear when I driving at nite hav to send to workshop the next day n check, so before I send in I hav to top up the engine oil before I go. The mach told me visual no oil leak so might b the piston ring problem n if yes I need to over haul it. They said since this is the 1st time I need to monitor another 1000 km see how much it less then only they check n confirm again. So I just ask the worst case happen how much I need to spend.