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Mr_D · 03-11-2015, 08:18 PM

Bought a '09 CC Magna with the ISX 650. Ran good for 3,000 miles or so then started running rough and threw a yellow check engine light. Did not derate. Got it towed to Cummins NW in Portland.
They suspect it's a dropped valve on #6. If so it's the second time it's happened in the same hole in 25,000 miles. No warranty left on either the original nor the repair.
The question is: why would a valve break twice in 25,000 miles in the same cyl. on an engine designed to go 750,000 miles before a top end job and 1,000,000 miles on the bottom end?

PushedAround · 03-11-2015, 08:23 PM

Sorry to hear about your troubles with such a nice coach. First question, was it the exact same valve? Second question, where did it break? Did the keeper fail or did the head break off the stem?

Mr_D · 03-11-2015, 11:32 PM

Quote:

Originally Posted by PushedAround

Sorry to hear about your troubles with such a nice coach. First question, was it the exact same valve? Second question, where did it break? Did the keeper fail or did the head break off the stem?

Can't answer either question as the original problem was in 2010 and we just bought the Magna three weeks ago. The service order says "broken in half" but that really doesn't answer the question. They did replace the turbo, piston, rod bearings, rings, liner, valves, head and injector in 2010.

sknight · 03-11-2015, 11:58 PM

A few things cause valve failure, a straight up defect (It just broke, it does happen.) a manufacturing defect in the head (Guide not correct, binding, valve seat cocked) causing the valve to be stressed, or a combustion issue overheating the valve.

I'm concerned, as everything involved apparently has been replaced. Here's what I would do if faced with failure analysis.

If it is the same hole, especially if it's the same valve as before, then I would look at what remains. Were the valves adjusted correctly? Was the bridge bar between the valves properly contacting the valve tip? The remains of the valve stem is very important, to try and figure out how it snapped, the top of the piston tells a tale also.

If it checks out mechanically, then combustion is what's left. I know the injector was replaced, but is there a restriction in the line causing a lean condition? Maybe a problem with the wiring and computer causing the injector to improperly fire? Could it simply be a faulty injector?

They should check the balance rates in the ECM to see if that cylinder was firing oddly before failure. The snapshot data should show the conditions at time of the engine light coming on, which was probably a misfire code.

Good luck and keep us up on the progress.

Mr_D · 03-12-2015, 12:09 AM

sknight:
Thanks for the info. They're still working on scheduling an open bay since it's a motorhome and takes more time and work area than a class 8 truck. Seems strange that they replaced almost everything in the failure area and it happened again. I don't ever want to have to go through this frustration and expense again! Wife is not happy as she really didn't want this unit in the first place so it's going to be a sore point for years especially if we end up paying the total cost! Rig needs new batteries and tires and the money we spend on the repairs will take all of what we need for that plus more.

CampingCajun · 03-12-2015, 07:39 AM

If possible try to find out if the replacement head was from Cummins or a reman from a parts house. I have had a few bad reman heads in trucks in the past. The price was attractive compared to one from Cummins but the quality wasn't there.

Mr_D · 03-12-2015, 10:05 AM

The first repair was at a Cummins shop and under warranty so I assume it was a new or Cummins reman part. But would have to follow up more to know for sure.

Waiting for the shop (Cummins NW) to get back to me with more info.

**CountryFit** · 03-12-2015, 03:00 PM

i feel your pain hopefully cummins will cover the cost as it is still under warranty...

Mr_D · 03-12-2015, 03:24 PM

No, it's out of warranty by a year. In service date was March 10 2009 so the 5 yr warranty was up on March 10 2014. The actual breakdown was March 7 2015.

sknight · 03-12-2015, 07:39 PM

Quote:

Originally Posted by Mr_D

No, it's out of warranty by a year. In service date was March 10 2009 so the 5 yr warranty was up on March 10 2014. The actual breakdown was March 7 2015.

Still, don't let that be an issue. First, it's a major failure at low miles. Second, it looks like it's a repeat failure of the same sort.

Pressure them, odds are at the least they'll goodwill all or part of it.

srh · 03-12-2015, 07:50 PM

Quote:

Originally Posted by sknight

Still, don't let that be an issue. First, it's a major failure at low miles. Second, it looks like it's a repeat failure of the same sort.

Pressure them, odds are at the least they'll goodwill all or part of it.

I totally agree!! They should.
In the event they don't, just make sure to get a membership to Cummins Power Club - you get 10% discount on all Cummins parts and Service.
Wish you all the best!

Mr_D · 03-12-2015, 09:03 PM

Quote:

Originally Posted by sknight

Still, don't let that be an issue. First, it's a major failure at low miles. Second, it looks like it's a repeat failure of the same sort.

Pressure them, odds are at the least they'll goodwill all or part of it.

Nope, don't plan on giving up! Too low a miles for it to happen again unless the original repair or parts used were faulty.
No word back from Cummins NW as to even if they have a bay available to start work.

Mr_D · 03-12-2015, 09:05 PM

Quote:

Originally Posted by srh

I totally agree!! They should.
In the event they don't, just make sure to get a membership to Cummins Power Club - you get 10% discount on all Cummins parts and Service.
Wish you all the best!

Did that when I filled out the work order, they added the cost to the order and we'll get the discount. It's already saved us $510.

srh · 03-13-2015, 08:28 AM

Quote:

Originally Posted by Mr_D

Did that when I filled out the work order, they added the cost to the order and we'll get the discount. It's already saved us $510.

Mr_D: We are all rooting for you and hoping all goes well! You are a wise man and you undoubtedly know the saying "...speak softly and carry a big stick...", I know it is very easy to get frustrated and you every right to be frustrated. I hope their (Cummins) wisdom on fairness to their constituencies will prevail!!

All the best!