Need help guys,
I have a 2004 chevy silverado ext. cab 2wd 4.8l v8. After it warms up at idle it has a knocking sound like a rod bearing. It just recently started and I only have 29,600 miles on her. Once you give it gas or rev it up the noise goes away for about 30 seconds then returns so that rules out the rod bearing. Drained oil today to see if there were any metal shaving and the oil was clean. the sound is at the bottom of engine towards the front. I am suspecting the oil pump or O-ring where the pickup tube goes into the pump.
Not sure though, has anyone ever had this problem or can you give me any ideas on a fix! Doesn't sound like piston slap!

Thanks

 

Mine does it too... Doesn't sound like slap but it must be cause I give it hell and its got 75k on it now..

 

If it's still under warranty, take it to the dealership, don't mess with it. And don't let them tell you it's a normal noise...that's bull

Lisa

 

Only got the 3/30,000 been expired by 6mon. They claim they will look at it and might cover under good faith warranty but only after they look at it. If they decide not to cover I'll only be out of pocket around $150.00. At that point if I'm out of pocket and they tell me its normal carractoristics of engine my next stop from dealer will most likely be the jailhouse after they call the law on me. LOL!!!

 

Have you had any problems with motor besides the noise? Did you have it looked at or find the cause? Like me I'm sure you would like to get rid of that noise. I want to build up but I'm afraid to for fear the motor is going to go out on me. It doesn't sound like piston slap to me either but sure would like to find out what the noise is.

 

Mine does that sometimes i have to the conclusion that its a lifter in my case...

 

mine use to do it, check your oil level, i replaced the water pump too. i know it sounds stupid..i also seafoamed mine and it stopped

 

I had a noise similar to yours and I even made a thread about it, after checking everything out I ended up doing a chemical engine flush using B.G. additives from my dealership and the noise is gone, I was very surprised.

Give it a try, it might help!

 

Listen, I had this same prob about a year after I bought the truck. It was back and forth to the dealership twice till I myself made the call to GM and crawled up someone's piehole to get something done.

The Regional GM rep made a trip to the dealership and it was said, "Fix It". Since then, there hasn't been a problem.

So maybe you can do the same. In the meantime, I will do my best to look thru my records to help, if I can.

Lisa

 

Thanks everyone, you have givin me some ideas to go on. I may try the seafoam first, then flush if seafoam doesn't work. It's an inexpensive shot in the dark anyway! Lisa, thanks for the advise on dealership. If all else fails that may be my last resort. If anyone has anymore ideas I'm all ears!!! I'm hesitant with seafoam/engine flush, seems like a bandage to a problem not to mention I feel it has to low of milage to have to do that!!! AGAIN THANKS