I know this topic has probably been addressed many times here, but what is the root cause of the # 4 line failures in CRs? I talked to a guy the other day who drives a 2011 service truck with 260k miles on it, and he said he was stranded once on the interstate with a #4 line failure... This seems to be an unresolved issue??

First I have heard of it, but there is a long debate on wether or not to replace the HPCR lines and cross tubes every time they are removed. From my experience with them on different engines and working with techs from different companies there are no real set answers. Our Detroit dealer replaces them every time they are removed to prevent a warranty claim if even 1 leaks if reused, Cummins techs are hit and miss but Cummins does reccomend replacing them whenever they are removed from the engine, it is a crap shoot. I have 2 co workers with CR cummins and they have both had bad experiences with reusing them after injector replacements and have had them go bad one at a time and had issues while on road trips and wound up getting towed to dealerships for new lines. They are both advocates of new lines and cross tubes everytime they are removed now from having bad experiences with reuse.Really a flip of a coin decision. Another coworker just replaced his injectors and has had a couple lines come loose on him already but refuses to replace the lines or tubes.

I was reading a thread awhile back and the subject came up.. I think AH64 said he even carries a spare??I looked mine over and it seems to be ancored quite securely in a nylon bushing:think: Just wondering if a guy ought to replace this at some point as a preventative?

I do carry a spare. The #4 is the most common line to break, and while it's not common it's also not rare. My understanding is the rubber clamp isn't tight enough and the harmonic vibrations cause it to fail. I check my clamp irregularly, and my dad's 06 too. I have never found either to be loose.

I check my clamp irregularly, and my dad's 06 too. I have never found either to be loose.

I check mine every so often also.........never been loose.

I towed a friend's 5.9 CR from a #4 line failure, he'd never pulled injectors. High milage truck... he had the clamp come loose on him one time after replacing the line. He bought a set of spares to keep in the truck just in case.I haven't heard if this is an issue on the 6.7. do they use the same lines? With the same bore spacing and injection pump I'd guess they could use the same complete fuel system, but I'm new to common rail so I don't know.

The 6.7 uses different, larger, lines.

After reading your stories about #4 line I just checked mine, 8 years and 105K miles, never been disturbed and still tight.

I checked mine also and it was tight. But now I have probably jinxed myself for sure.You know how when you wash your car it always rains.Please, Please, I don't want this problem.

Dumb question? Is there a way to upgrade to the 6.7L lines as a possible upgrade?

Dumb question? Is there a way to upgrade to the 6.7L lines as a possible upgrade?

http://www.glacierdieselpower.com/product.aspx?pf_id=030767-MRS Thou from what I gather you had better be in the 1K plus range on hp for it to make much of a difference. The biggest benefit, IMHO, would be the wide mouth intake manifold and horn.

http://www.glacierdieselpower.com/product.aspx?pf_id=030767-MRS Thou from what I gather you had better be in the 1K plus range on hp for it to make much of a difference. The biggest benefit, IMHO, would be the wide mouth intake manifold and horn.

Wow! thats a bit more than I`m looking to bite off LOL! part off what perked my interest in this was the fact that I know at least one 2011 6.7 has blown a #4, and it seems to be something systemic with the CR:shrug: Maybe its just as simple as checking your line brackets as part of your regular maintenence??? It just seems peculiar it always seems to be the same line:think:

Here is a shot of the new style of line clamp that the dealership put on my truck last month when the #4 line broke.

That's interesting. IF I was to want to carry a spare #4 injector tube is this only a dealer item or are they available through any source? I suppose the new style clamp is probably only a dealer item.

They are obtainable thru Cummins, and from what I recall they are cheaper too.

They are obtainable thru Cummins, and from what I recall they are cheaper too.

I decided to get one for myself and just keep for insurance purposes. The Cummins dealer had them in stock. The part number is 5289447 and it cost $26.28. It comes with the new style clamp that drscott got when he had the dealer replace his #4 line.

The Cummins dealer had them in stock.

I think that says a lot.

After reading this thread ,I have a spare one under the back seat of my truck..