i went to the auto part thinking to replace the lifter today then again this guys recommended me not to because its waste of money and it sounds normal for high k's holden engine so instead they gave me another engine oil 10w30 to try well the noise slightly gone but i still feeling paranoid that the rattle still there lol
seriously this issue hasn't really effected my car performance but it does effecting my tolerance level
To be honest, that does sound like an average high kms Ecotec, I wouldn't be too worried about it randomly exploding or anything.
The lifter treatment some of the guys have suggested might solve your problem, it's cheap and easy to try at any rate.
If it were me I'd be running a 20w50 in an engine with 280,000kms on it. 10w30 is quite thin, and would have been Ok when the engine was new, but by now it'd probably benefit from a thicker oil. I've found the Shell high-milage stuff to be good in those motors, but any of the big name brands should be alright. It's not something you'd need to run off and do, but when the next oil change comes around it's what I'd recommend. I would also say that if you are doing regular changes at 5,000kms, that you needn't worry about using synthetic oil (there's no harm if you do, but you won't gain much from it).
