[NavyCuda]

Has Nissan been giving a clear reason why the low pressure turbo is being replaced on the trucks that need it?

I just looked at the low pressure turbo that I got, that had been replaced as failed. No oil in the exhaust, shaft play is minimal, no blade contact or damage. The casting doesn't even have rust on it yet, so it's out of a low km truck. The only thing I can find is that the rotary valve seems to bind up easily. The rotary valve is part of the turbine housing casting, so if they wrote off the valve/casting they'd do the whole turbo. The rotary valve is removable though, so is Nissan just deciding they want to replace the turbo instead of fixing the valve?

 

[Two Yeets]

I'd be interested to see a solid answer on this. Surely they're not replacing an entire turbo without a good reason.

 

[JoeyS]

I wouldn't be surprised if the cop-out response when the dealers don't have real diesel techs is just replace the complaining part...

 

[Two Yeets]

Good point. With the diesel variants produced for only 4 years in small numbers, their techs probably have no idea how to work on them.

 

[NavyCuda]

Good point. With the diesel variants produced for only 4 years in small numbers, their techs probably have no idea how to work on them.

My dealership hired a diesel tech who formerly worked at their Dodge or Ford dealerships... I can't remember which. He didn't know he had removed the high pressure turbo when he was replacing the low pressure turbo that I got. The other factor isn't just finding and fixing the problem, it's the hours that Nissan has to pay the dealership to do the job. If it's an eight hour job (just guessing) to replace the low pressure turbo it could add another eight hours to correctly diagnose a problem with the rotary valve. Those extra eight hours could add another $1000 to the bill. Ignoring the complex geometry of the turbine housing, which is probably the most expensive part, the turbo is a big, fixed geometry holset. Not expensive to make. So I bet from a total job perspective it's probably cheaper to replace the whole turbo than the rotary valve.

My guess is that the plan was to send in the old low pressure turbos to be rebuilt and go back out to the parts network as new replacement turbos. Once production ended, Nissan and Cummins had no reason to bother building repair infrastructure.

 

[realbored]

My dealership hired a diesel tech who formerly worked at their Dodge or Ford dealerships... I can't remember which. He didn't know he had removed the high pressure turbo when he was replacing the low pressure turbo that I got. The other factor isn't just finding and fixing the problem, it's the hours that Nissan has to pay the dealership to do the job. If it's an eight hour job (just guessing) to replace the low pressure turbo it could add another eight hours to correctly diagnose a problem with the rotary valve. Those extra eight hours could add another $1000 to the bill. Ignoring the complex geometry of the turbine housing, which is probably the most expensive part, the turbo is a big, fixed geometry holset. Not expensive to make. So I bet from a total job perspective it's probably cheaper to replace the whole turbo than the rotary valve.

My guess is that the plan was to send in the old low pressure turbos to be rebuilt and go back out to the parts network as new replacement turbos. Once production ended, Nissan and Cummins had no reason to bother building repair infrastructure.

The turbo doesn't come as a complete unit. You have to order each separately. To replace it under warranty pays between 4.5-5 hours (to replace intake gaskets pays around 4.5 hours). As far as diag time goes, if there is a bulletin for the code you basically get the replacement time. If there isn't a bulletin you might get a couple of hours for diag.

 

[Rolling20s]

The letter I received in the mail, states that they are replacing the turbo actuator and the high-pressure turbo as needed. Not the low pressure turbo. My service manager showed me some of the units they have replaced. The shaft on the actuator is sticking kind of like an old worn out carburetor butterfly linkage shaft bushing would wear out and cause it to stick. That’s the analogy he used. I felt it on one they had replaced and it’s noticeably sticky.

 

[Two Yeets]

I wonder if it's possible to simply take it apart, clean the moving components, and apply some grease. I could see enough dirt and crap building up and creating a lot of reistance with moving parts.

 

[NavyCuda]

I wonder if it's possible to simply take it apart, clean the moving components, and apply some grease. I could see enough dirt and crap building up and creating a lot of reistance with moving parts.

It’s part of the manifold. no grease will survive that. The hotter the exhaust, the faster it wears out.

edit: brain fart, circle and laugh!

 

[Two Yeets]

Good point. I was thinking of the controller, not the valve itself.

 

[NavyCuda]

Good point. I was thinking of the controller, not the valve itself.

No no, I mean to laugh at me. I thought you were talking about the valve and not the actuator. So it was me that got confused. I think.

 

[Mark Crenna]

My 2017 Nissan Titan XD diesel has just been diagnosed with low speed turbo failure. Codes indicated on a scan it was low doors turbo by dealership and by an independent Cummins diesel garage. Is there any extended warranty on low speed turbo as there is one for the high speed turbo.
I live in Ontario Canada. Nissan is out of low speed turbos as there on back order.

 

[NavyCuda]

I wonder if your turbo has actually failed (unlikely) or if it's just the rotary valve sticking...

 

[Rolling20s]

I, too, have received the code, stating the rotary valve is sticking open. The tech says it’s more than likely the low pressure turbo that is causing it. I am really curious why Nissan is extending the warranty on the high-pressure turbo when it seems that the low pressure turbo is the one with the issues.

Not sure if anybody has looked it up, but I just looked up the part number for the turbo assembly and it says it’s discontinued. That can’t be right. They have to offer parts for these trucks for at least 10 years.

 

[Tiger Fan]

My 2016 has been kicking a P226C code randomly for the past few months. Finally took it to the local dealership and tech discovered sticking RTCV. The repair is replacement of the low-pressure turbo since the rotary valve is built into the turbo housing. The tech discovered this by disconnecting the actuator rod from the RTCV and attempting to move the valve itself which was extremely tough to do. It was so tight that when he reconnected it, he couldn't perform the required calibration, which meant rolling the dice to get it home. He suspected carbon build up which is not uncommon for this motor. I started it up and drove it locally to get the intake hot and maybe loosen the valve which worked well enough to perform the calibration and get it home. I have since sprayed PFTF lube onto the valve housing and linkage ball joint which seems to have loosened it a little. Just drove truck today for a few miles and no dead pedal or CEL. This all started when temps dropped so not sure if cold carbon is causing the binding or if that is just coincidental. From pics it looks like you can remove the valve, and maybe replace it, but to be honest, I'm looking for another truck. Tech commented parts are hard to find and expensive. Love how this truck drives, rides and pulls but I want some road confidence. And the aftertreatment on this truck is unreliable as well as extremely expensive. Too bad Cummins didn't choose a better turbo set-up because this truck would have been a home run. As for the high-pressure turbo and RTCV actuator, I believe this is specific to the 2016. Seems the turbos in that year had an oiling deficiency causing premature wear of the turbo and potentially sending shavings into the engine. I bought mine used and the high-pressure turbo had already been replaced.

 

[NavyCuda]

My 2016 has been kicking a P226C code randomly for the past few months. Finally took it to the local dealership and tech discovered sticking RTCV. The repair is replacement of the low-pressure turbo since the rotary valve is built into the turbo housing. The tech discovered this by disconnecting the actuator rod from the RTCV and attempting to move the valve itself which was extremely tough to do. It was so tight that when he reconnected it, he couldn't perform the required calibration, which meant rolling the dice to get it home. He suspected carbon build up which is not uncommon for this motor. I started it up and drove it locally to get the intake hot and maybe loosen the valve which worked well enough to perform the calibration and get it home. I have since sprayed PFTF lube onto the valve housing and linkage ball joint which seems to have loosened it a little. Just drove truck today for a few miles and no dead pedal or CEL. This all started when temps dropped so not sure if cold carbon is causing the binding or if that is just coincidental. From pics it looks like you can remove the valve, and maybe replace it, but to be honest, I'm looking for another truck. Tech commented parts are hard to find and expensive. Love how this truck drives, rides and pulls but I want some road confidence. And the aftertreatment on this truck is unreliable as well as extremely expensive. Too bad Cummins didn't choose a better turbo set-up because this truck would have been a home run. As for the high-pressure turbo and RTCV actuator, I believe this is specific to the 2016. Seems the turbos in that year had an oiling deficiency causing premature wear of the turbo and potentially sending shavings into the engine. I bought mine used and the high-pressure turbo had already been replaced.

The m2 turbocharger setup is the best and most performant turbocharger setup available for a pickup. Emissions is what screwed this truck. That valve also gets extremely hot in stock configuration and most delete tunes.

The high pressure turbo is the turbo that does the vast majority of the work. The low pressure turbo doesn’t even start to light until 2200rpm.

I don’t have numbers from stock which is a major foresight on my part, but deleted trucks are hitting 177,000 rpm on the high pressure turbo and the calibrated max is 165,000. Seeing exhaust back pressure at 77 psig and the calibrated max is 65. It’s not the turbos, it’s the calibration and all the bs to satisfy emissions.

 

[Two Yeets]

Too bad Cummins didn't choose a better turbo set-up because this truck would have been a home run.

I think the Holset M2 is an incredible turbo system, it just doesn't like soot buildup. Neither do variable geometry turbos, and many wish our trucks had one of those instead of the M2. I think you just need to clean the turbine housing to the best of your ability. Perhaps taking it apart as much as you can and blasting everything with brake cleaner will do the trick. No sense in replacing the whole truck over a little carbon buildup, if that is the issue.

 

[Tiger Fan]

Agree the Holset performance is top-notch...just not confident in the lubrication system for the HP turbo. It's obviously an issue, at least with the 2016 models. And Cuda is right, the emissions components are major culprits with maintenance problems in these trucks. There was a 2017 parked next to mine at the dealership waiting on a DPF pump, EGR cooler and one other emissions part. Tech said lead time is 2-6 months.

I could definitely pull the turbo and clean the valve, but the fact that I need to pull a turbo with 76K miles doesn't instill a lot of confidence. Especially when I hear a tech tell me that they are having more of these trucks show up for work and have less parts to support the platform. Definitely a tough decision...when this truck is on, I wouldn't want to drive anything else. But the writing seems to be on the wall with lack of available parts.

 

[realbored]

Not sure if anybody has looked it up, but I just looked up the part number for the turbo assembly and it says it’s discontinued. That can’t be right. They have to offer parts for these trucks for at least 10 years.

The turbos are available individually and not as an assembly.

 

[Tiger Fan]

I was looking at a 15-day lead time for my turbo, which in my opinion, is very acceptable. I also did a quick search on line and found both turbos at Z1 Offroad for roughly the same price. The remove/replace looks pretty straightforward with the exception of re-calibrating the actuator. Again, having to remove the turbo for cleaning or replacement at 76K should not be part of scheduled maintenance.

On a potentially good note, I just re-installed my factory air box yesterday so I have an S&B CAI intake for sale cheap!