Cold start up engine noise
 

After starting the engine when it's cold (after sitting for more than 5 hours), once the engine is at idle, I hear some sort of light knocking noise at idle that sounds almost like piston slap. The sound only lasts for about the first 30 or so seconds after a cold start, then goes away. Is this a normal characteristic of the Alpha engine, or something I should take to the dealer for? It's done this even before I changed the crappy Quaker State dino oil for Mobil 1 synthetic, and I even used a genuine Hyundai oil filter (and always will). I thought I would ask before I run to the dealer lot, just to start another Accent with a cold engine and listen, before I go to service dept.

2011 Hyundai Accent Engine Knock?
 

Greetings,

Any updates on this one? Philippine 2011 Hyundai Accents have been experiencing these phenomenon lately, My brother is interested on buying the new Accent but while we were researching about it we encountered multiple owners having this problem of engine knocking noise. Some suggested it maybe just the rating of the unleaded fuel that was used but most already use 95+RON rating fuel and the knocking noise persists..

Are there any explanation to this? Looks like this is not isolated to the Philippine release of Hyundai Accents?

I test drove another '10 Accent, they all do it for the first 10-20 seconds after cold start, then goes away. Dosen't do it when it's warm when started. It's normal for these cars, with the 1.6 engine. I found premium unleaded gas seems to up the performance with this engine, and also shortens the cold start crank time a bit, even though it's ment to run on regular grade unleaded.