1. If the engine is start at low temperature and it is making "jeng jeng" noise, bluish smoke coming out from exhaust pipe togeher with harsh vibration, it could be the temperature of the engine during start up is too low which causing lack of lubrication in the cylinder, making the cylinder skirt grinding with cylinder wall. Such condition can be ignore for now and continue to drive, but suggest to send to workshop for diagnose later.
2. If the engine is start at low temperature and it is making "jit jit" noise, it could be the temperature is too low causing the already aged alternator v-belt lose its flexibility become hardened, hence producing frictional noise. Such condition can be ignore for now and continue to drive, but suggest to send to workshop for diagnose later.
3. If the engine is start at low temperature and it is making "pong pong" noise, it might be some issues on the lubricant circulation. Cold start in a low temperature condition causing poorer protective lubricating film, resulting in dry fricitonal noise produce from lack of lubricating in the engine. Majority of the root cause is due to the car is not service on time, or using a low quality lubricants which do not meet requirement. Such condition can be ignore for now and continue to drive, but suggest to send to workshop for diagnose later.
Suggest to perform diagnose at work shop, usually the keypoints of diagnose from the mechanic are:
1. Check if the lubrication of the engine still in good condition, suggest to use the lubricant oil which meet the technical requirement with suitable vicosity. A lubricant that is too thin will cause grinding wear more easily while a lubricant that is too thick is less fluidic, causing more friction.
2. Check the wear condition on the internal mechanism of the engine, suggest to perform periodic maintenance to the car on a timely manner, it could greatly help in minimize the wear in the engine and prolong the car lifespan.