Diesel RV Club, an FMCA Chapter

Ask Dave => Hey Dave, I've Got a Problem => Topic started by: jumpwake on June 10, 2020, 04:43:53 PM

Title: Cummins ISB - 3 bad turbos in 2 years
Post by: jumpwake on June 10, 2020, 04:43:53 PM
New to the RV club this year.  I just bought a 2007 Freightliner Gulf Stream - FRED.  Has the 5.9L ISB Cummins - VGT turbo.  Previous owner had a power issue in 2018, several new items installed, including a new Turbo.  New parts in 2018: Both fuel filters, pressure relief valve, seals, EGR valve, Turbo HE351W, fuel lift pump.  Basically trying to solve loss of power.

I believe this solved his problem for a bit, but he took it back to Cummins dealer 10 months later complaining of high pitch whistle, CEL.  Codes 2961, 2962.  Dealer found a "big leak" at the Ex. Flex pipe from the egr valve.  Installed new flex pipe and clamp.  Filter rubber cracked, installed new filter....and replaced Turbo under warranty.

Fast forward to me buying.  We immediately take RV out for 2500 mile trip.  Seemed to run pretty well, until one HOT day...CEL came on when lugging up hills, clutch fan would run loud...then CEL would go off when I would ease up and the hill was over with.  The entire trip I did notice a very high pitch whine (not super loud) that changed with my rpms, but not having enough experience with it...I wasn't sure if it was just normal turbo pitch.

When we got home, I took it into local big rig shop.  I had an oil service done and the CEL light checked out.  Same inactive codes: 2961, 2962.  All visible inspections by them of the EGR and temp sensor looked good.  They ended up replacing 2 clamps and a new temp sensor.  Updated ECM (bricked it) and sent to Cummins to reflash.  After getting ECM back, took long test drive and did get a CEL to pop up.  2388, and inactive 2961, 2962.  2388 = VGT - Out of Calibration.

I had local shop call the last shop that replaced the Turbo and discuss this considering the Turbo is only 11 months old.  They basically tell me I need a new Turbo.  I basically brought the MH home so I can digest this and figure out what to do.  Currently its not displaying any codes, I'm assuming it would if I took it out on a hot day and let it work a bit.

Sorry for the long post, just wanted to be as detailed as possible.  I'd love to speak with someone with more experience with the ISB - VGT.  I realize the VGT is not ideal...not sure if I should just replace the actuator, or look into an aftermarket "Fixed" Geometry Turbo.

Looking for suggestions!

Serial Number: 46624833
Title: Re: Cummins ISB - 3 bad turbos in 2 years
Post by: David.e.atherton on June 11, 2020, 07:13:29 PM
Jumpwake, reading and reviewing your problem on turbocharger problem. My suggestion take you motorhome to a Cummins Service shop. This repair involves connection of Cummins InSite technical service testing tool.
I have mixed thoughts with the 5.9 engine is a simple troublefree operation engine. If perhaps incorrect part
replacement may have caused second turbo to fail but there are many factors present if not addressed by
a trained mechanic and not finding the root cause of failure you can lose your engine. Let the trained mechanic
troubleshoot and find the root cause. Not what you want to hear but will save you lot of money ahead.
Ask Dave, Dave Atherton Retired Cat Mechanic
Title: Re: Cummins ISB - 3 bad turbos in 2 years
Post by: jumpwake on June 12, 2020, 05:00:54 AM
Thanks for the reply.  The first turbo was installed by Cummins certified shop, the 2nd was at Cummins.  I don't plan on wrenching on this myself, but I'm just seeking as much info as possible.  I know Cummins won't replace the actuator alone anymore.  I do not know if they had it on Insite or not, but I can ask.
Title: Re: Cummins ISB - 3 bad turbos in 2 years
Post by: David.e.atherton on June 12, 2020, 07:06:27 AM
jumpwake, you mention wastegate actuator not being replaced again, yes actuator replacement had several
Problems and that practice had been stopped several years ago. The only way that turbo can be now replaced with A complete assembly. The variable wastegate actuator is a non- serviceable. You are doing the correct
approach on this problem wanting to find the root cause of Same part failure. My suggestion go with new
Turbo complete and not a reman or good used turbo. There many reasons for failure and the tear down and
inspection of your present turbo failure is the aftermath. Have Cummins Factory opinion something is being
overlooked because your problem is very rare. Ask Dave, Dave Atherton Retired Cat Mechanic