My friend has a 2009 Accord with a 2.4L engine that has a rough sound at startup. I attached a file. Initially I thought it might be a timing belt issue, but I believe the 2009 2.4L has a timing chain. The car sounds normal after startup. The oil is at the right level (though don't know when the oil was last changed). The car has about 131k miles. Any idea what the sound might be related to. I haven't test drove it yet, but will try it out later this weekend.

 

Sounds like the vtc actuator is going

 

I believe that is the hydraulic tensioner failing. When the car starts up the tensioner is not pushing out fast enough (by lack of oil pressure at startup) causing the chain to have slack and rub against the guides. When was your last oil change. I have a car that has done this and I changed the weight and no problem since. I've put about 15k on it since the change. Or you can get a timing kit and fix the issue completely.

Hydraulic tensioners fail prematurely or have early issues due to the lack of changing the oil or oil type being put in. On the newer accord full synthetic is best keeping everything lubed as it should and less gunk. I've been using 0w20 for about 5 years (switched from 5w20 full synthetic). I would clean the crankcase (Lucas or sea foam for 150 miles) and put 0w20 in to see what you get before deciding to change the tensioner. Once you drive a cycle with 0w20 which should fix your issue change the oil to back 5w20 full synthetic (Walmart brand is what i use. It's all the same) and I also use the original Honda filter (1st gen). It is still working and just needs proper lube for initial startup.

 

Agree w/ Poorman. This is a common problem. I have intermittently had this on my 2010 TSX. See following video.


good luck