{"id":13025,"date":"2020-04-15T12:30:25","date_gmt":"2020-04-15T16:30:25","guid":{"rendered":"https:\/\/techlink.mynetworkcontent.com\/?p=13025"},"modified":"2020-11-30T11:32:26","modified_gmt":"2020-11-30T16:32:26","slug":"duramax-diesel-warm-engine-idle-knock-sound","status":"publish","type":"post","link":"https:\/\/gm-techlink.com\/?p=13025","title":{"rendered":"Duramax Diesel Warm Engine Idle Knock Sound"},"content":{"rendered":"<p class=\"western\"><span style=\"font-size: 12pt;\">Some 2020-2021 Silverado 2500HD\/3500HD and Sierra 2500HD\/3500HD trucks equipped with the 6.6L Duramax diesel engine (RPO L5P) may have a thumping or knocking sound coming from the rear of the engine. The sound is often more pronounced in the interior of the truck as it\u2019s amplified by the transmission bell housing.<\/span><\/p>\n<p class=\"western\"><span style=\"font-size: 12pt;\">To duplicate the engine sound:<\/span><\/p>\n<ul>\n<li><span style=\"font-size: 12pt;\">Idle the engine at about 600 RPM with the transmission in Park or Neutral. The engine oil temperature should be 113\u2013185\u00b0F (45\u201385\u00b0C). <\/span><\/li>\n<li><span style=\"font-size: 12pt;\">Turn the HVAC fan and radio off.<\/span><\/li>\n<li><span style=\"font-size: 12pt;\">Remove the accessory drive auxiliary belt. (Fig. 14)<\/span><\/li>\n<\/ul>\n<p class=\"western\"><span style=\"font-size: 12pt;\">If the noise level is significantly reduced, it should be considered a normal characteristic. No additional repairs are necessary.<\/span><\/p>\n<p class=\"western\" style=\"text-align: center;\"><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter size-full wp-image-13010\" src=\"https:\/\/techlink.mynetworkcontent.com\/wp-content\/uploads\/2020\/04\/F14-knock-1.png\" alt=\"\" width=\"740\" height=\"480\" srcset=\"https:\/\/gm-techlink.com\/wp-content\/uploads\/2020\/04\/F14-knock-1.png 740w, https:\/\/gm-techlink.com\/wp-content\/uploads\/2020\/04\/F14-knock-1-300x195.png 300w, https:\/\/gm-techlink.com\/wp-content\/uploads\/2020\/04\/F14-knock-1-85x55.png 85w, https:\/\/gm-techlink.com\/wp-content\/uploads\/2020\/04\/F14-knock-1-200x130.png 200w\" sizes=\"auto, (max-width: 740px) 100vw, 740px\" \/><span style=\"font-size: 12pt;\"><b>Fig. 14<\/b><\/span><\/p>\n<p class=\"western\"><span style=\"font-size: 12pt;\">Use the following procedure for accessory drive auxiliary belt removal, testing and installation:<\/span><\/p>\n<ol>\n<li><span style=\"font-size: 12pt;\">Remove the air cleaner housing.<\/span><\/li>\n<li><span style=\"font-size: 12pt;\">Remove intake air duct.<\/span><\/li>\n<li><span style=\"font-size: 12pt;\">Separate the charge air cooler (CAC) tube and position aside.<\/span><\/li>\n<li><span style=\"font-size: 12pt;\">Remove the belt and position aside.<\/span><\/li>\n<li><span style=\"font-size: 12pt;\">Install the CAC tube.<\/span><\/li>\n<li><span style=\"font-size: 12pt;\">Loosely place the air box and intake duct back in place. (So a DTC is not set for the sensor when starting.)<\/span><\/li>\n<li><span style=\"font-size: 12pt;\">Start the engine and verify the sound is gone.<\/span><\/li>\n<li><span style=\"font-size: 12pt;\">Remove the loosely installed air box and intake duct.<\/span><\/li>\n<li><span style=\"font-size: 12pt;\">Separate the CAC tube.<\/span><\/li>\n<li><span style=\"font-size: 12pt;\">Install the belt.<\/span><\/li>\n<li><span style=\"font-size: 12pt;\">Install the CAC tube.<\/span><\/li>\n<li><span style=\"font-size: 12pt;\">Install the air box and duct.<\/span><\/li>\n<\/ol>\n<p class=\"western\"><span style=\"font-size: 12pt;\"><b>TIP:<\/b> Do not run the vehicle more than three minutes without the auxiliary belt installed. Do not raise the RPM higher than idle with the belt removed.<\/span><\/p>\n<p class=\"western\"><span style=\"font-size: 12pt;\">The engine sound has no short- or long-term effects on the engine.<\/span><\/p>\n<p class=\"western\"><span style=\"font-size: 12pt;\"><i>&#8211; Thanks to John Stempnik<\/i><\/span><\/p>\n<p>&nbsp;<\/p>\n<p><em>Updated November 30, 2020<\/em><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Some 2020-2021 Silverado 2500HD\/3500HD and Sierra 2500HD\/3500HD trucks equipped with the 6.6L Duramax diesel engine (RPO L5P) may have a thumping or knocking sound coming from the rear of the [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_exactmetrics_skip_tracking":false,"_exactmetrics_sitenote_active":false,"_exactmetrics_sitenote_note":"","_exactmetrics_sitenote_category":0,"footnotes":""},"categories":[1],"tags":[],"class_list":["post-13025","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"_links":{"self":[{"href":"https:\/\/gm-techlink.com\/index.php?rest_route=\/wp\/v2\/posts\/13025","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/gm-techlink.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/gm-techlink.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/gm-techlink.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/gm-techlink.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=13025"}],"version-history":[{"count":4,"href":"https:\/\/gm-techlink.com\/index.php?rest_route=\/wp\/v2\/posts\/13025\/revisions"}],"predecessor-version":[{"id":14057,"href":"https:\/\/gm-techlink.com\/index.php?rest_route=\/wp\/v2\/posts\/13025\/revisions\/14057"}],"wp:attachment":[{"href":"https:\/\/gm-techlink.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=13025"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/gm-techlink.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=13025"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/gm-techlink.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=13025"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}