I own a Santro Exec 2005. Recently I ran into this problem. The engine gives a sound on hard acceleration. I get most of the work done from Hyundai Sowan Motors Rawalpindi. I asked one of the guys there and he told me that this is a crank sound and it can only be fixed by overhauling.
Engine turns heavy even on 10KM/hour and sound starts coming. I won't call it noise because the sound is hardly noticeable.
No oil decrease issue.
No smoke issue.
Timing belt recently changed.
The mechanic said that I should keep the car running. I won't need overhaul in next 1.5 years provided that I don't hard accelerate. BUT that's not the solution. I highly suspect that complete overhaul is necessary in this case.
Is there any way that only crank can be repaired? I fear, that if I keep on running the car in this condition, that would wear pistons, valves, rings and other stuff in the engine.
Suggestions highly appreciated.
PS: btw they gave me an estimate of at least 65K for complete overhaul.
PPS: Please recommend me a good mechanic in Rwp/Isb who is dedicated and committed to his work.