You knopw what it reminds me of is the rod knock noise you would hear in the old V-8s. I did'nt hear it yesterday at start up. Who knows.

 

Hmm, my only other question would be: was the correct weight oil put in? Just trying to help you eliminate any "simple" possibilities...

Later
Allex

 

Yep 5W30




Goose

 

I have an 08 hhr 2.4 engine. It has the same noise in the motor, sounds like no oil in motor for 2 or 3 seconds when i crank it up after setting all nite or for a day or two. New oil, new filter. 34,000 miles on it. Thie noise sounds like it could cause unnessary wear on the motor parts. Sounds almost like a rod knock. Runs and sounds good other than that. Does not do it all the time, just every now and then. Maybe some of the more experienced chevy boys will have an idea as to what this noise is and how to fix it.
Thanks

 

I've had this once in the month or so I've had my '07 2LT 2.4, it happened after she was parked for 2 days....... parked for one day or overnight it hasn't happened. If it happened everyday I would be very worried...... as it is I listen for it every start.


...... it does sound like rod knock.

 

Any update on this?

I just got my 2009 & its happened about 3 times now. I agree that it sounds oil related. To me its like a lack of oil supply to the top of the engine. Specifically the valvetrain.

Any info would be great.

Thanks.

 

Sounds like the issue I had with my 2007 2.4L. On cold days or when it sat overnight, every once and a while I would get a 3 second rattle at startup. I narrowed it down to my Serpentine belt. I replaced that and have not heard the noise ever again. My belt was only 37K miles old.

My first though was Valvetrain, But It was the Belt.

 

I have a 2011 2.4L that started having that noise but not regular. Sounded just like a dry oil start with rod noise.

I took it into the dealer and by leaving the car overnight and going in to start it myself with the mechanic in the car the next morning.
Luckily it did it that morning, and he said .. I know what it is.
They replaced the Serpentine Belt and I haven't had a noise since then.

I went in at about 9,000 miles and I have 13,000 now.

I would have never guessed that was the problem as I am very knowledgeable about engine noises both 2 stroke and four stroke and can usually call the problem myself.

 

So what exactly is causing the belt to make a "knocking" noise? If replacing it worked for some of you, could you explain what the problem was with the original belt.

 

Ah, that's makes some sense now.

Think about it.

What happens when the belt stretches past the point at which the spring in the tensioner can keep the belt tight? During startup there's inertia in the system resisting the belts motion. Since the tensioner is trying to keep the belt taught and can't due to being near the end of its stroke (resulting in minimal spring tension) the tensioner slaps its limit stop repeatably until everything is moving smoothly. Thus being the momentary clattering noise we hear.

Just a theory, I could be wrong but based on your experience it makes sense to me.