Engine Noise

[keptor30]

1999 GMC SIERRA 5.3L 4x4 174000 miles. Truck never had any noises or issues. It sat for 3 1/2 years and I went to start it and it wouldent turn and seemed to be locked up. Tried it a couple more times and it kicked back and snapped the ear off the starter. I got a new starter and pulled all spark plugs. one cylinder was filled to the top with fuel but the rest were dry. I installed new plugs and started the engine. it runs and idles but there is a extremely loud noise comming from the right side. It is even louder during increased rpm but when you left off the throttle it goes away for a couple seconds and continues at idle. The motor is misfiring badly and has a random misfire code only. sounds to me like a piston is hitting a valve. Any ideas?

[00Silverado4x4]

Is it possible that you have an exhaust leak? These engines were known for breaking manifold bolts. It may be something external so check everything over closely.

[02suburbanZ71]

Exhaust manifold should sound like a ticking. It normally goes away when the engine is warm.

[jhm]

could be a lot of things. real loud knocking could be a connecting rod bearing. just a guess based on past experience.

[Coffeehound]

^{Sounds like it was hydro locked with fuel and you bent a connecting rod when you turned it over. Thats my guess.}

[keptor30]

There is no compression in the first cylinder bank 2. Same cylinder that was hydrolocked.

[Snow White]

I'd pull the valve cover off, pull all the plugs again and turn it over manually to see if the valves move... presuming the cylinder was full of fuel, it's likely the intake valve was froze open and you smashed it when you started it up and the head of the valve is hitting the piston or it's floating around and you're smashing the broken valve top against the cylinder head... either way... it's bad news and hopefully you haven't wrecked the cylinder wall beyond a honing or bore job.

 

to me, it sounds like that engine is coming out of that truck.

[Mervkirwin]

Hey, just wondering took my truck on a road trip, noticed a noise coming from the ride side rear like as if something was rubbing, I could get rid of the noise by playing with the gas peddle. Just wondering if anyone has had the same or simpler problem. Thanks

 

 

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[02suburbanZ71]

Hey, just wondering took my truck on a road trip, noticed a noise coming from the ride side rear like as if something was rubbing, I could get rid of the noise by playing with the gas peddle. Just wondering if anyone has had the same or simpler problem. Thanks

 

 

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Probably rotors or pads. I had a similar situation.