GM I6 Diesel Impressions

[Tractorable]

Something I didn’t see mentioned in this thread are some of the questionable engineering choices GM made with this 3L diesel.

The oil pump is driven by a rubber belt located on the back of the engine. It has a 150k mile service interval and the transmission has to be dropped to change it. It has “active coolant management” which is numerous coolant valves actively routing coolant to different parts of the engine based on what the computer decides. It also has a dual EGR emissions system.

This might be all fine and dandy while under warranty, but if you buy used trucks, or are the “buy and hold” type who plans to drive the truck for hundreds of thousands of miles, it’d behoove you to be aware of the thousands of dollars you’ll be paying to maintain it.

This is going to be a huge cash cow for the dealerships because when they’re billing you a few grand to pull the transmission to replace the $20 rubber belt, it’d be the perfect time to upsell you on overhauling your 150,000 mile GM transmission, or low-ball you on a trade-in. By then, the cost of the service might be more than the truck is worth.

 

[Industrial Toys]

Thanks for that. I think I just lost all interest. They can keep their RUBBER belt. Just Like the VW timing belt!

Makes the thing worthless as a DIESEL except for bragging rights.

I guess my idea of what a diesel engine is all about and that of these "NEW" Engineers is quite different.

 

[Hay Dude]

Thanks for that. I think I just lost all interest. They can keep their RUBBER belt. Just Like the VW timing belt!

Makes the thing worthless as a DIESEL except for bragging rights.

I agree That is a less desired way to run a oil pump. However, I would add also that most of our vehicles would be disabled by a belt failure, like a serpentine belt failure, too.
I could probably see my way to working with a belt driven oil pump IF it was accessible without removing the transmission. THAT is pretty ridiculous

 

[Industrial Toys]

Reminds me of a friend that bought a Generac with Mitsubishi engine, for use on his Gas Wells, so something expected to accumulate hours in a hurry. He went ballistic when he found, not only that they had a non metalic timing belt, but that it was an interferance engine!

 

[Sawyer Rob]

Thanks for that. I think I just lost all interest. They can keep their RUBBER belt. Just Like the VW timing belt!

Makes the thing worthless as a DIESEL except for bragging rights.

I guess my idea of what a diesel engine is all about and that of these "NEW" Engineers is quite different.

It does have a rubber belt, but it's a timing chain in the rear and you do have to pull the tranny to change it.

I didn't think you had to pull the tranny to deal with the rubber belt though?

SR

 

[Tractorable]

The timing chain and the rubber oil pump belt are both on the back of the engine and require removal of the transmission to service.

 

[Sawyer Rob]

The timing chain and the rubber oil pump belt are both on the back of the engine and require removal of the transmission to service.

OK, thanks for updating me on that. SR

 

[lostcause]

The timing chain and the rubber oil pump belt are both on the back of the engine and require removal of the transmission to service.

I'd put money that says something seemingly trivial and emissions related will cause you a big hurt to the wallet long before something mechanical will on a new diesel. As much as I may like a certain vehicle I'm not going to get emotionally attached to a new diesel daily driver like this. These new diesels are great as long as you aren't paying the repair bill. Once that happens you will wish they are someone else's.

 

[s219]

Here's a good video on the engine -- they talk about the oil pump belt in the first couple minutes.

What you don't know about the 3.0-liter Duramax diesel - YouTube

 

[Hay Dude]

I'd put money that says something seemingly trivial and emissions related will cause you a big hurt to the wallet long before something mechanical will on a new diesel. As much as I may like a certain vehicle I'm not going to get emotionally attached to a new diesel daily driver like this. These new diesels are great as long as you aren't paying the repair bill. Once that happens you will wish they are someone else's.

And I壇 be betting same right alongside you. I lost DPF systems on all 3 of my 08 Superduty 6.4L diesels. One was replaced by previous owner. One I did by buying a used one off a young man who decided to remove his for $700 and the other I traded in on my RAM with a shot DPF. Dealer didn稚 care or even check.
Done by Ford with Ford parts, it was a $3,000+ job.

 

[tookielee]

Slide tranny back a little, then pull a cover to access the belt?
Doesn't sound that bad, after 150K miles. A couple of months
ago, I had to pull a turbo off of the Ecoboost to change a 50 cent
O-ring.. day and a half job at home, dealer wanted 900.00 minimum
for the job. All of the manufacturers are making equipment that is
hard to access for repairs

 

[Hay Dude]

Slide tranny back a little, then pull a cover to access the belt?
Doesn't sound that bad, after 150K miles. A couple of months
ago, I had to pull a turbo off of the Ecoboost to change a 50 cent
O-ring.. day and a half job at home, dealer wanted 900.00 minimum
for the job. All of the manufacturers are making equipment that is
hard to access for repairs

Some of the Ford 6.4L Diesels will develop a drip of oil, that progressively gets worse. It’s an oil return line for the turbo.
Now you won’t believe this, but its about $1,000 to perform this repair for a tiny o ring fitting.
These engineers are truly numb to the repair costs of these trucks. THEY DONT CARE.

 

[tookielee]

Mine was the coolant return line fitting on the turbo

 

[WM75Guy]

Some of the Ford 6.4L Diesels will develop a drip of oil, that progressively gets worse. It’s an oil return line for the turbo.
Now you won’t believe this, but its about $1,000 to perform this repair for a tiny o ring fitting.
These engineers are truly numb to the repair costs of these trucks. THEY DONT CARE.

It is to generate service business, which is what keeps a dealer open. To change the left headlight bulb in my 08 the instructions starts with "Remove the grill to get at the bolts so you can remove the left fender". After that you can remove the headlight housing and change the bulb pretty easily. Whoever thought that was an OK process is definitely a company man.

 

[pmsmechanic]

It is to generate service business, which is what keeps a dealer open. To change the left headlight bulb in my 08 the instructions starts with "Remove the grill to get at the bolts so you can remove the left fender". After that you can remove the headlight housing and change the bulb pretty easily. Whoever thought that was an OK process is definitely a company man.

I was supposed to do the same thing on my friends 2017 F-150. I figured I'd be wise to watch a YouTube first. There was a short clip on just pulling the front half of the fender liner back and replacing the bulbs. Defiantly easier and faster to do than removing the grill.

 

[ruffdog]

Some of the Ford 6.4L Diesels will develop a drip of oil, that progressively gets worse. It’s an oil return line for the turbo.
Now you won’t believe this, but its about $1,000 to perform this repair for a tiny o ring fitting.
These engineers are truly numb to the repair costs of these trucks. THEY DONT CARE.

Some of those you have to pull the cab to get to.

 

[Hay Dude]

Some of those you have to pull the cab to get to.

The sad thing is, the 6.4L is a monster of an engine. It runs/drives like a gas big block, but has the torque of a diesel, of course. The sequential turbos are great, but not of the highest quality design for reliability. The rocker arms in the first year of the 6.4L were built too light and wore out, requiring replacement most times at about 150k miles.
It will go down in history with a bad reputation because of the way it was engineered into the truck for service and the awful DPF system shutting off a cylinder to regenerate and the related nonsense.

In other words, if the 6.4L was a pre ‘08 non DPF engine, it would be excellent. A real runner and worker.

 

[Snobdds]

The sad thing is, the 6.4L is a monster of an engine. It runs/drives like a gas big block, but has the torque of a diesel, of course. The sequential turbos are great, but not of the highest quality design for reliability. The rocker arms in the first year of the 6.4L were built too light and wore out, requiring replacement most times at about 150k miles.
It will go down in history with a bad reputation because of the way it was engineered into the truck for service and the awful DPF system shutting off a cylinder to regenerate and the related nonsense.

In other words, if the 6.4L was a pre ‘08 non DPF engine, it would be excellent. A real runner and worker.

I agree the 6.4 is the hotrod of diesel engines. The twin sequential turbos put a lot of air into the engine off idle and at WOT. It was a beast, but that **** thing was hard to work on because it was so shoehorned into the engine bay. Deleted and a few fixes to the top end of the engine, made them reliable. Plus it had that bombproof transmission behind it that just never failed.

I kinda wish ford would put a twin turbo on the 6.7, but the VGT is a pretty good design.

 

[Hay Dude]

I agree the 6.4 is the hotrod of diesel engines. The twin sequential turbos put a lot of air into the engine off idle and at WOT. It was a beast, but that **** thing was hard to work on because it was so shoehorned into the engine bay. Deleted and a few fixes to the top end of the engine, made them reliable. Plus it had that bombproof transmission behind it that just never failed.

I kinda wish ford would put a twin turbo on the 6.7, but the VGT is a pretty good design.

It kind of goes to show that light truck engineers are what failed the 6.4. Their DPF system design was junky and expensive to repair and replace. If they would have done their R&D more carefully, it would have been a good engine. Youre right, it was shoehorned into the truck without proper testing or consideration for those who had to work on them.
The rocker arm issue is the fault of International, but they did resolve it. They should have stepped up and replaced all the early rockers for free. The turbos are super high performance-almost hot rod in design, but not extremely durable, either. The oil cooler is another known issue. The number of coolers and the complexity of cooler lines is a problem. If they could have improved on the design, it could have been an awesome diesel.
Like you said, the Torqshift transmissions are a home run.

 

[Snobdds]

It kind of goes to show that light truck engineers are what failed the 6.4. Their DPF system design was junky and expensive to repair and replace. If they would have done their R&D more carefully, it would have been a good engine. Youre right, it was shoehorned into the truck without proper testing or consideration for those who had to work on them.
The rocker arm issue is the fault of International, but they did resolve it. They should have stepped up and replaced all the early rockers for free. The turbos are super high performance-almost hot rod in design, but not extremely durable, either. The oil cooler is another known issue. The number of coolers and the complexity of cooler lines is a problem. If they could have improved on the design, it could have been an awesome diesel.
Like you said, the Torqshift transmissions are a home run.

In Ford and International's defense, the emission part was not totally their fault. The EPA was putting so many rules in place it was hard to keep up with the technology needed to meet those rules. The DPF was a totally new concept in 2008 and nobody really knew how to add it in and make it work correctly. Every manufacture had issues early on. The EPA should have allowed for OEM's more time to get the technology right before they released it in the wild.