rdkspkrv Report post Posted August 1, 2017 Stopped at dealer this past Friday to have window shades repaired. Upon exiting the coach noticed diesel running down the side of the engine and under the coach. This was on a Tiffin Phaeton that I bought new and was 1 yr old on July 28, only 8,000 miles. Turned out to be a crack in the fuel line. Fortunately, the Cummins center in Kenner, LA has the part but that required a 180 mile round trip. Borrowed brother in laws car and got the part to the dealer before closing,. 30 minutes later we were on the road. Understand this may be a common failure with this engine......any others experiencing this problem. BTW the new fuel line had brackets on it to limit vibration... Appears Cummins knows it's a problem. Seems like they should do a recall on this. Not a safe situation! Share this post Link to post Share on other sites
wildebill308 Report post Posted August 1, 2017 Welcome to the forum. It would appear the adding of the brackets is the fix. With the line stabilized it shouldn't crack again. Where was the crack? Bill Share this post Link to post Share on other sites
rdkspkrv Report post Posted August 1, 2017 Near the entrance point to the engine. Share this post Link to post Share on other sites
wildebill308 Report post Posted August 2, 2017 I think the added brackets will keep the vibration down. Bill Share this post Link to post Share on other sites
erl4702 Report post Posted August 26, 2017 I have had this happen twice. Yes, Cummins knows there is a problem, but it is not a recall problem according to them. It's the #1 fuel line. Share this post Link to post Share on other sites
BillAdams Report post Posted August 26, 2017 Wow, that happened on my 1995 Cummins engine. The fuel line just split lengthwise. It was the #6 line and when they tried to get that line it kept coming back with all 6 lines. There was an undeclared recall and if one line went they were to replace all lines. This happened to have happened on our way out of an FMCA Perry rally (our first) while headed to a Freightliner rally in GA. It blew along the way and we limped up the hills on 5 cylinders with instructions from Cummins on how to do so. They took REALLY good care of us at the rally! Share this post Link to post Share on other sites
gallatinflash Report post Posted September 8, 2017 Just last week we returned from a short trip to The Big South Fork National Recreation Area. As we pulled into our subdivision I noticed smoke and diesel spray near the engine compartment. Our tow car was covered in diesel. After getting the Motor home to the Freightliner dealership in Nashville, it turned out to be a broken fuel injector line. We have close to 6,000 miles and bought this 2016 Newmar Ventana new last November. Just today I learned that this problem with Cummins is a regular occurrence. Fortunately the warranty covered towing and repairs. Share this post Link to post Share on other sites
Kgeistfeld Report post Posted December 22, 2017 We just purchased a new 2017 Dutchstar and got it home and tried to start the engine and after 9 hours and a diesel mechanic later, find out it needs the same correction! The part is in but Cummins and Freightliner said another week to two because their mechanics are laid up? We have had our coach 2 months and never been able to enjoy it! Not a fun way to start RV'ing (Especially after spending so much money!). We had plans to use it for Christmas and took time off work and all the plans are futile. I have written Newmar the dealership, Freightliner and Cummins . Wish we wouldn't have bought a Newmar! Share this post Link to post Share on other sites
jleamont Report post Posted December 22, 2017 This seems to be a problem with other engine manufactures also. I just had a freightliner Tractor yesterday with a Detroit engine do the same thing, it was shooting fuel onto the turbocharger, no fire just a bunch of smoke from the fuel burning off. Share this post Link to post Share on other sites
hermanmullins Report post Posted December 22, 2017 Joe, Do you think these failures are due to too much Bio-Diesel? Causing seal and hose disintegration. Herman Share this post Link to post Share on other sites
jleamont Report post Posted December 22, 2017 21 minutes ago, Hermanmullins said: Do you think these failures are due to too much Bio-Diesel? Causing seal and hose disintegration. No, the lines that are failing are metal. I have seen them crack, almost as if the metal composition was wrong for the application i.e. hardened to the point that it shatters or cracks like glass. Given the amount of PSI in todays diesel engines (some into 40,000 psi) running through them, the lines are stressed beyond what their metal can handle, toss some vibration into that and they fail, we wont get into what country they were probably sourced from also doesn't help matters...... Share this post Link to post Share on other sites
hermanmullins Report post Posted December 22, 2017 How far back are the failing parts going? As in manufacturing of the engines and are the failures across all manufacturers ? Herman Share this post Link to post Share on other sites
jleamont Report post Posted December 22, 2017 It looks like 3-4 years is as far back for this issue.... in general. The Detroit that failed yesterday was a 2018 unit with 4200 miles on it. Other issues began when the EPA shoved the emissions systems down everyone's throat. I have had injection pumps fail from the casting not being able to handle the PSI and it boaring a hole in them on a 2012 Cummins ISL and a 2007CAT C7S. With that kind of pressure spraying around an engine compartment you can do some serious bodily harm, its like a water jet CNC machine. Share this post Link to post Share on other sites
dickandlois Report post Posted December 22, 2017 Joe, You might take a look at this link. Lines Available in SS or other materials They can make about any tube for any make and model vehicle and engine. If they do not - sending them the tubing information and bending pattern / even an OEM line as a pattern and see what they say. They also make Brake lines and kits. Classic tube Lancaster NY 1-800-882-3711 http://www.classictube.com/index.php Rich. Share this post Link to post Share on other sites
jleamont Report post Posted December 22, 2017 Great link Rich, thank you. Share this post Link to post Share on other sites
hermanmullins Report post Posted December 22, 2017 Are we speaking of the individual lines from the pump to each cylinder? I am not that familiar with the diesel fuel supply system. What might be the PSI from the injector into each cylinder? If it is close to 40,000 PSI could that erode tops of pistons and even cylinder walls? You can see by my questions I know ever little about Diesel Engines. Herman Share this post Link to post Share on other sites
jleamont Report post Posted December 22, 2017 The Cummins failures so far have been between the "rail" and injectors. This video explains how some Cummins systems operate. Share this post Link to post Share on other sites
jleamont Report post Posted December 22, 2017 The one I had was the 7th injector line, which supplies fuel to the exhaust after treatment system. Share this post Link to post Share on other sites
hermanmullins Report post Posted December 22, 2017 Joe, does this mean that all of the lines after the Hi pressure pump are subject to the reported line failure? Herman Share this post Link to post Share on other sites
jleamont Report post Posted December 22, 2017 8 minutes ago, Hermanmullins said: Joe, does this mean that all of the lines after the Hi pressure pump are subject to the reported line failure? Herman It seems like the longer ones fail more frequently. Speculation; vibration due to the length? I have seen one fail after the pump before the rail but it looked like it was bumped during engine installation or while working on something else. When I say bumped, it had a dirt mark, no bend or scratch on the paint. Share this post Link to post Share on other sites
hermanmullins Report post Posted December 22, 2017 Thanks, learned more each day and hope to continue learning. Herman Share this post Link to post Share on other sites
jleamont Report post Posted December 22, 2017 9 minutes ago, Hermanmullins said: Thanks, learned more each day and hope to continue learning. Herman You're welcome, Anytime buddy! Share this post Link to post Share on other sites
Kgeistfeld Report post Posted September 17, 2018 On 8/1/2017 at 1:25 PM, Rdkspkrv said: Stopped at dealer this past Friday to have window shades repaired. Upon exiting the coach noticed diesel running down the side of the engine and under the coach. This was on a Tiffin Phaeton that I bought new and was 1 yr old on July 28, only 8,000 miles. Turned out to be a crack in the fuel line. Fortunately, the Cummins center in Kenner, LA has the part but that required a 180 mile round trip. Borrowed brother in laws car and got the part to the dealer before closing,. 30 minutes later we were on the road. Understand this may be a common failure with this engine......any others experiencing this problem. BTW the new fuel line had brackets on it to limit vibration... Appears Cummins knows it's a problem. Seems like they should do a recall on this. Not a safe situation! Our fuel rail had to be replaced the first week we brought it home 2017 Newmar Dutchstar. Its in the shop currently for emissions problems! Frustrating! Share this post Link to post Share on other sites
richard5933 Report post Posted September 17, 2018 Interesting thread. I know that it started quite a while ago, but I had a similar thing happen on a Yanmar diesel engine in a tractor. Primary fuel pump housing cracked after only a few hours, causing a pretty serious fuel leak. When I got the warranty replacement it had an improved mounting system with added brackets. Same thing happened a couple of months later when the air cleaner mounting brackets cracked. What was explained to me is that diesel engines are often set up and tested in one application. For example, the unit on my tractor was apparently designed and tested to be used as a skid steer engine. When it was repurposed as a tractor engine it was suddenly being called to run at a different RPM. This change in RPM caused a different vibration pattern to set in, and with it various problems such as the fuel filter and air cleaner mounts. I'd be curious if something like that happens with the engines being put in motor homes. They were originally designed and tested for use in one application with a specific transmission combination (OTR trucks with a manual transmission, for instance), and then the engineers decide to put that engine in a motor home to increase power. They combine it with an automatic transmission, and suddenly the engine is running at a speed slightly different than originally tested and along come problems like cracked fuel lines. Just a working theory, and I'd be interested to see what others think. Share this post Link to post Share on other sites
jleamont Report post Posted September 17, 2018 Richard, I’d bet you are onto something. I ran into this before in a utility vehicle, when the engine was designed no one thought about the Lineman in the air for several hours with the engine at idle with the PTO engaged and the truck goes into regen and raises the rpm’s, truck got real jerky like a carnival ride almost tossed a few out of the bucket, the fix caused more frequent tows away from a job site. Share this post Link to post Share on other sites
