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Topic: Cummins ISX valve problem (Read 2597 times) previous topic - next topic

Cummins ISX valve problem

We bought a 2007 Nimbus in 2018 with a 400 hp Cummins. In december 2018 later found a 2008 Phenix with the 600HP ISX so bought it and sold the Nimbus. Took the coach to a Cummins shop for a full service and replaced a leaking EGR cooler ($5000). The engine had eaten a valve prior to my ownership in 2014 (36k miles) and had a new cylinder head,turbo and some pistons replaced so I asked them to do a compression check. Was told Cummins does not recommend or do compression checks. Have since found out the valve in question can be inspected with a bore scope thru the injector port for about $300 labor. We put 10K miles on the coach this summer (now has 64K miles).
While traveling down I 85  Sept. in Noth Carolina the engine ate same #6 valve which took out the turbo and piston leaving us stuck along the side of the road for 2 days. Had to have the coach towed to Cummins shop 20 miles away for $2000.
During the repair process( $29000) Cummins informed us that they have had a Technical Service Bulletin
(TSB 150130 dated 05-Dec-2016) detailing the valve/seat failures and the introduction of improved material in the valve/seats installed in new cylinder heads.
Installing these improved heads can be done for under $5000 but Cummins doesn't have a system to inform/contact owners of the engines about the fix to avoid the expensive problem with a road side breakdown and engine damage.
We suggest any owners of coaches from 2007 to 2016 with ISX engines check with a Cummins shop and get a copy of Service Bulletin to avoid the catastropic failure we experienced.

Re: Cummins ISX valve problem

Reply #1 –
I am going to look that up. I was at Cummins in July  right before it went out of warranty and they didn't say anything about this
2014 ih45  (4th Foretravel owned)
 1997 36' U295 Sold in 2020, owned for 19 years
  U240 36' Sold to insurance company after melting in garage fire
    33' Foretravel on Dodge Chassis  Sold very long time ago

Re: Cummins ISX valve problem

Reply #2 –
Sorry to hear of your troubles.  This is a well-known issue with the ISX and Cummins is NOT standing behind it.  We won't touch a coach with that engine

New engine

ISX problems again? - iRV2 Forums

Cummins ISX broken valve in #6 - iRV2 Forums
Learn every day, but especially from the experiences of others. It's cheaper!  - John C. Bogle

2000 U320 36' non-slide / WildEBeest Rescue
2003 U320

Re: Cummins ISX valve problem

Reply #3 –
Quite a few other forum posts about Cummins eating valves, especially the 600-650HP ISX. A good friend's cousin came to town for vacation from the Phoenix area. He works at a Cummins shop and also said that #6 cylinder is the one that fails the most.

Faulty valves are a possibility. Valves are generally two-piece with the stem welded on to the head. It is a controlled process with the proper grade of metal and welding needed so it can withstand the high heat.

Valve seats are another possibility. The cylinder head has to be machined accurately and the seat pressed in correctly so it cannot come loose at high temperatures. If it does come loose, it will drop down a bit, turn sideways enough so it can't go back into position and then the valve cannot go back on it's seat and is hit by the piston. Valve seats are frequently manufactured

The cooler a valve operates, the less likely it is to fail. Since a valve transfers much of it's heat to the valve seat, the amount of time it spends on the seat is important, in other words, the valve have to be adjusted to factory clearances. Running high EGTs especially in high temperatures and high altitudes can cause the valve material to weld itself to the valve seat resulting in elevated operating valve temperatures over long period of time.

Higher HP ratings always mean more heat is generated under loads that generate high EGTs.

Nothing I can think of would point to number 6 cylinder as being more failure prone.

No excuse for Cummins not having all owners in a database to be contacted with the latest tech info.

Go to this link to come up to speed on valves and valve seats: Valves and Seats - Engine Builder Magazine).

Pierce

Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)

Re: Cummins ISX valve problem

Reply #4 –
And to think, all those years ago in a home shop in Easthampton, MA, a solitary worker installed hardened valve seats in the block of my Ford T engine and I never had a problem.

1992 Foretravel Grand Villa
U225 SBID Build No. 4134
1986 Rockwood Driftwood
1968 S.I.A.T.A. Spring
1962 Studebaker Lark
1986 Honda VF700C
1983 Honda VF750C
Charlie, the Dog was broken out of jail 24 Oct 2023
N1RPN
AA1OH (H)e who must be obeyed.

Re: Cummins ISX valve problem

Reply #5 –
The lust for coaches with max (unneeded) HP is a costly adventure in brochure bracket racing.

Be nice though if Cummins would at least stand behind their product and post tech bulletins. And of course this illustrates why a diesel pusher (esp the ISX) needs to have a EGT gauge. Or at least learn to hit that down arrow on the shift pad.
Jerry & Nona and Kimeru the cat that thinks she's a dog
1998 36' WTFE U320  #5314 Motorcade #17711
USAF 1975-1995
2019 Subaru Crosstrek 'toad'
2003 Subaru Legacy touring car
jerry Fincher | Flickr

Re: Cummins ISX valve problem

Reply #6 –
Does your coach have a post EGR with regeneration cat, or just EGR.  I ask because I have been following this situation and most of the issues were with engines equipped with the new regeneration cats.  Also seems most prevalent in ISX 650's.

Re: Cummins ISX valve problem

Reply #7 –
My understanding especially as evidenced by Brad here is spiriting driving might lessen the odds of failure.

"Riding and rejoicing"
Bob
1997 U320 40' Mid entry, build 5132,  wtbi ce27, 4th owner
2007 Solara convertible
2 prodeco tech outlaw ss electric bikes

1095 watts solar
08 Ls 460 and a sc430
2000 Ford F-250 superduty 4x4

Re: Cummins ISX valve problem

Reply #8 –
After being down two years, our ISX 500 has been fixed. We are a 2012 nimbus. The number six valve is farthest away for cooling and also gets blow back on the egr crap. The egrsystem is not well made and despite some folks dislike of Bernd Ramspeck, he has corrected ours with a filter that is metal similar to what BMW and Mercedes-Benz uses in their Diesel vechicles. We no longer have a clogged up filter putting pressure on our #6.  Cummins couldn't say how long their filter would work, so we went with the substitute that Bernd had researched. Several of us tried to get a class action going, but so far nothing has been done.
Lynn and Linda Day and Harry the pug
RIP: Tank 01-2008 to 03-2020
2012 Nimbus 42' build 6555
ISX12-500hp
2015 Jeep Grand Cherokee
MC# 17723

Re: Cummins ISX valve problem

Reply #9 –
Based on your comments you have a particulate filter as part of emissions. What I found out is those engines pre particulate filter do not seem to exhibit the problem. My engine a 2007 built unit was the last engine produced without the particulate filters and the need to regenerate and have a high heat engine.

Re: Cummins ISX valve problem

Reply #10 –
Quote from: esaulten –
Also seems most prevalent in ISX 650's.

It's hitting any ISX.  Showed up in the 650's first, but many 600's and a couple of 500's have been reported.
Learn every day, but especially from the experiences of others. It's cheaper!  - John C. Bogle

2000 U320 36' non-slide / WildEBeest Rescue
2003 U320

Re: Cummins ISX valve problem

Reply #11 –
Michell true but again after PMing some of the rv forum members with ISX 600 issues their engines had the new particulate filter needed in 2008 engines by new emissions law.  it was later amended to include DEF. 

Re: Cummins ISX valve problem

Reply #12 –
Even the 5.9 is not immune. I remember a member with a 5.9 at Quartzsite in 2014 lost #6 the year before. Losing a valve in one cylinder usually effects the cylinder next to it also. Not that it make much difference in the cost to repair unless you do it yourself. It does not always ruin the head and a good shade tree mechanic may be able to do a fairly inexpensive repair.

Pierce
Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)

Re: Cummins ISX valve problem

Reply #13 –
Quote from: esaulten –
Michell true but again after PMing some of the rv forum members with ISX 600 issues their engines had the new particulate filter needed in 2008 engines by new emissions law.  it was later amended to include DEF. 

This is major issue that should be referred to with as much specifics as possible. I own a 2007 Phenix with a 2006 ISX600 CM870 engine. I have over 99k miles on it and have not had this issue. My engine does not have a DPF (particulate filter).
Previous coach - 2007 Phenix 45'

Re: Cummins ISX valve problem

Reply #14 –
Lots of links to sites that address the model/year of engines that have had problems and the fixes. Here is one link to read. Cummins ISX Problems and Failures | Highway & Heavy Parts Others easily found with forums or YouTube videos. I'm a big Detroit fan but have a lot of respect for a Cummins N14. Lots of good reads here: how to avoid cummins isx valve problems - Google Search

Pierce

Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)