Eastcoastdiesel Posted November 9, 2016 Share Posted November 9, 2016 Hey yall! I am back it seems. Now that life seems to have slowed down a bit. Right now however I have an issue. The same truck in the title, the flexpipe seems to have expanded from heat, and gotten damaged. I have the parts to fix damage... what is causing this?? As yall know I don't deal with dpf macks. This truck hails from my Sparta Tennessee location. Any help?? Quote Link to comment https://www.bigmacktrucks.com/topic/47621-2008-mack-cxu613-exhaust-problem/ Share on other sites More sharing options...
Timmyb Posted November 9, 2016 Share Posted November 9, 2016 I've not seen flex pipe like that before. It looks quite thin, although it's hard to tell from photo. The type I've used is as per photo below. Mind you, I doubt it could flex that tight radius your after. Quote Link to comment https://www.bigmacktrucks.com/topic/47621-2008-mack-cxu613-exhaust-problem/#findComment-351434 Share on other sites More sharing options...
Mackpro Posted November 10, 2016 Share Posted November 10, 2016 Here's a bulletin on it. Read it carefully. They had alinment problems and you had to also change another pipe. Early flex pipe issue.pdf 1 Quote Link to comment https://www.bigmacktrucks.com/topic/47621-2008-mack-cxu613-exhaust-problem/#findComment-351537 Share on other sites More sharing options...
turckster Posted November 11, 2016 Share Posted November 11, 2016 If the flex pipe looks "expanded" or pushed out, it is most likely cause by excessive back pressure. Either the dpf is plugged or the cataylist is plugged or both. You need to find out why this happened. A face plugged cataylist is usually caused by a poor flowing 7th injector. Quote Link to comment https://www.bigmacktrucks.com/topic/47621-2008-mack-cxu613-exhaust-problem/#findComment-351596 Share on other sites More sharing options...
ERoberts Posted November 15, 2016 Share Posted November 15, 2016 On 11/10/2016 at 10:10 PM, turckster said: If the flex pipe looks "expanded" or pushed out, it is most likely cause by excessive back pressure. Either the dpf is plugged or the cataylist is plugged or both. You need to find out why this happened. A face plugged cataylist is usually caused by a poor flowing 7th injector. turckster OP is a pre DPF operator. The issue was very prevelant to our CXU series series but if the SB is followed yo should have no other issues. Quote Link to comment https://www.bigmacktrucks.com/topic/47621-2008-mack-cxu613-exhaust-problem/#findComment-352020 Share on other sites More sharing options...
turckster Posted November 15, 2016 Share Posted November 15, 2016 4 hours ago, ERoberts said: turckster OP is a pre DPF operator. The issue was very prevelant to our CXU series series but if the SB is followed yo should have no other issues. Being a CXU chassis and a 2008 model, this chassis is equipped with a dpf unit. The service bulletin addresses alignment issues of the flex pipe and proper repair. The customer complaint is expansion of the flex pipe. The only thing that comes to mind, for me, is excessive back pressure. Not meaning any disrespect, just saying. Quote Link to comment https://www.bigmacktrucks.com/topic/47621-2008-mack-cxu613-exhaust-problem/#findComment-352031 Share on other sites More sharing options...
ERoberts Posted November 16, 2016 Share Posted November 16, 2016 18 hours ago, turckster said: Being a CXU chassis and a 2008 model, this chassis is equipped with a dpf unit. The service bulletin addresses alignment issues of the flex pipe and proper repair. The customer complaint is expansion of the flex pipe. The only thing that comes to mind, for me, is excessive back pressure. Not meaning any disrespect, just saying. You are !00% right i am in the wrong there. I jumped the gun and excluded the given facts after he claimed PRE DPF status. Rookie mistake. Thanks for setting me straight Turckster. Quote Link to comment https://www.bigmacktrucks.com/topic/47621-2008-mack-cxu613-exhaust-problem/#findComment-352097 Share on other sites More sharing options...
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