2006 5.3 Engine knock

PSSC · January 10, 2019

2006 silverado 5.3 130k 2wd

Symptoms - knock coming from drivers side wheel well. doesnt seem to be exhaust leak as it sounds mechanical metal to metal type sound. it doesn't happen directly on start up but as it warms up to about 205 degrees then stops as it reaches roughly 210 degrees. This is the only time it happens. Some times it is louder than others. some times it seems to last a little longer than others.

I have tried sea foam and a flush the place that does my oil changes recommended. Neither seemed to work for more than a few days.

I have read it could be piston slap but that seems to be more on start and disappears after warm up. there seems to be no loss of power before or during knock.

Oil pressure reads fine while knock is happening. As I write this I remember replacing the oil pressure sensor and feel like the knock might have started after that at some point.

I will try and post a video of the noise shortly.

riverbanks · January 10, 2019

You could use a 3' wood dowel for a stethoscope,one end to ear other to various places to try to isolate the noise

garagerog · January 10, 2019

No CEL or codes? Curious this happens only in a 5 degree window of coolant temp. Throwing something out there that may be off the wall, but I wonder about a lazy or faulty knock sensor.

PSSC · January 11, 2019

No codes. Just took it through emissions and passed no problem.

Link to video of the knock.

PSSC · January 14, 2019

Any one else have any suggestions or insight into this issue?

SouthPawCO · January 14, 2019

Hard to tell from the video but it sounds like a rod knock. They generally are louder until the engine warms up and can fluctuate in noise level. It's been awhile since I've heard piston slap but I don't recall it ever being that loud and obvious. I'd try a can of BG MOA and see if that helps any.