Terrible idle clatter at high elevation

[Spoolmak]

So we're on our annual fall road trip south with the camper on the truck. She's running beautifully hauling along on the hiways - smooth and great fuel economy, 16 mpg with camper on, 22+ with camper off. In Bishop CA, we stop for several days, take the camper off, and explore the high lakes. Yesterday, the first place, South Lake, elevation 10,000 feet when I pull into the parking lot and let her idle a bit to cool down before shut down, she clatters like crazy. She smooths right out when rpm is increased, but clatters when back at idle. Once we run back downhill into the town at 4000 feet elevation, she's smooth and quiet again. Same scenario today running up to North Lake.

The fuel filter was changed a two months ago - 5000 miles or 8000km ago. Did oils and filter changes just before we left. No codes showing or pending. She has 98,000 miles(151,000km) on the odometer. Injectors were replaced Oct 28, 2009 at 86,000 miles or 130,000km on the odometer.

I'm baffled. Does anyone have any ideas??

Sitting in Bishop, worried! :-(

Tor

[DmaxMaverick]

Don't be worried. It's completely normal. At 10,000 feet, the worst sound your Diesel engine can make is......Silence. There isn't as much O2 in the air, so it complains. Once off idle, the turbo helps cram some more in. That's the nature of the beast. Some engines, Diesels included, won't run at all, at that elevation. As long as everything returns to "normal" once at lower altitude, it's fine. Rest easy and enjoy your time in one of the most breath-taking places on the planet.

[Spoolmak]

Don't be worried. It's completely normal. At 10,000 feet, the worst sound your Diesel engine can make is......Silence. There isn't as much O2 in the air, so it complains. Once off idle, the turbo helps cram some more in. That's the nature of the beast. Some engines, Diesels included, won't run at all, at that elevation. As long as everything returns to "normal" once at lower altitude, it's fine. Rest easy and enjoy your time in one of the most breath-taking places on the planet.

Thank you for the quick response and setting my mind at ease!!!!!

This certainly is a breath taking place. Tomorrow we go into Yosemite for two nights - a place we've wanted to go visit as long back as I can remember.

Tor