I have had this problem ever since I have owned my car. Been about 1 month now and every time I start it up after I let it sit for more than maybe an hour or 2 it makes this sound like marbles are being grinded together inside the engine for maybe 2-3 sencods then idles nice and quiet. I thought it was engine knocking but then I learn what engine knocking was and it wasn't it. So I am really confused on what it could be because I don't know if it could cause harm to the engine if I keep driving and neglect it.

I have only used 92 octane and the previous owner has all the maintinence records up to 63,000 miles. The car now has 66,000 miles on it and I have been hearing it about 2-3 days after I bought it a month ago. It doesn't make anything sound when I step on the gas ONLY at cold start ups. Then it goes away after 2-3 seconds. I am so confused what it could be. I am pretty sure its not knocking because knocking occurs only at higher RPMS right?

Is the:
-Timing belt going bad?
-Auto tensioner?
-Busted motor mount?
-Spark plugs?

 

can you hear it in the head or in the block next time have someone start it while you have the oil filler cap off and put your ear to it to hear if it is in the head or not

 

Last time I had a sound like that it was my tensioner

 

yea, either tensioner or could be bearings from what you are describing. most likely auto fail tensioner

 

Can you guess tell me what an auto tensioner does? Does it tighten or loosen the timeing belt? How much would it cost to replace it?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by HS2G &raquo;</TD></TR><TR><TD CLASS="quote">Can you guess tell me what an auto tensioner does? Does it tighten or loosen the timeing belt? How much would it cost to replace it?</TD></TR></TABLE>

It tensions the timing belt, automatically.

The actual part isn't that expensive. But the labor to remove and replace it will pretty steep if you don't want to do it yourself.

 

If your hearing that marbles sound, chances are you have already bent some valves. I find it strange that it would go away after two or three seconds on start up.

 

Yea it goes away after 2-3 seconds or sometimes it doesn't make a sound and just turn over nice and smooth.

 

I had this same problem and just got my auto tensioner and timing belt changed and my noise seems to have gone away. I thought it might be bent valves too but my mechanic said that you would prob know if the valves are bent and I couldnt notice any power loss or stalling. So its prob just the auto tensioner