akadeadeye Report post Posted March 15 Our 2009 Newmar Allstar mid-engine ISL 400HP diesel engine is making a whistling sound when climbing hills. Not nearly as much whistle, if any, when descending. Any thoughts? Don Share this post Link to post Share on other sites
wildebill308 Report post Posted March 16 Could be just the turbo. Your boost will be higher when it is working harder. I would check all the connections to see if any are leaking or loose. Bill Share this post Link to post Share on other sites
rayin Report post Posted Thursday at 08:00 AM In addition to what wildbill suggested,(and I suspect he's right) inspect the exhaust manifold for any leaks. There will be black soot at a leak/crack. Share this post Link to post Share on other sites
