Pinging Rattle Under Hood

beach3141 · April 13, 2016

I have a 2015 LTZ Z71 with the 6.2. I love the truck and have had it a bit over 6 months, just over 5K miles to date. About a month and 500 miles ago, it suddenly developed a metallic rattling noise seemingly coming from under the hood, and sounds similar to an engine that pings on bad gas, just not nearly as loud - but CONSTANT. I've fueled my truck with premium gas ever since new. The strange thing about this rattling noise, is that it doesn't start until I'm going 35-40 mph, and keeps rattling as I speed up as well. It makes the noise even when I'm off the gas, so it doesn't appear to be related to load on the engine or anything. When I slow down for a light or to make a turn, once I get under 30mph or so, the noise goes away. I've had it at the dealer for several days now and they are having no luck determining what is causing the noise... nothing in any service bulletin addressing something like this. The assistant service manager is bringing in some field support/technician/engineer to look into this more. I like my truck, don't want to "lemon law" it... I just want it fixed. I paid too much $$$ for this truck to put up with that sort of annoyance with so few miles on it. Plus... no one has been able to say for sure that it isn't engine related, and that continuing to run the truck as-is, won't end up causing damage down the road. Anyone else hear of anything like this? Anyone?

ejdziurka · April 13, 2016

Exhaust heat shield?

beach3141 · April 13, 2016

I'll keep that in mind when the truck goes back in for more troubleshooting next week. I didn't get to talk with the mechanic that was actually working on it for three days, so I'm not certain what he all looked at.