1million mile isx15 never been touched - what now?

[dccustomfarms]

I have just purchased a 15 model 389 Peterbilt with a million miles and 30k hours on the clock. Previous owner stated that the head, or the pan has never been off. I bought it knowing it was about do for rebuild. I have always had caterpillar engines. It's always been my practice to do rods and mains around every 300k mark. Are the red engines different? A million seems pretty far.

My question is, do I pull the pan and replace rod/main bearings? Inspect liners, and possibly change oil pump? Or do I go ahead and do complete in frame? Engine has good oil psi and very minimal blowby. Or should I run it a bit and see how it acts, and measure oil consumption? I do not want to do anything premature, but also don't want to take a chance of a rod destroying the block. From my research, a large percentage of these engines only make it to the 3-400k mark before failure. In this situation, what typically fails? Blown gaskets? Massive blow by and oil consumption? Or is it a ticking bomb wait to explode?

I do all of my own repairs and am not in hurry to put the truck on the road. Trying to decide the best approach for this situation. And also trying to learn the way of the red. Thanks for any and all input.

[hhow55]

If it were mine........Mr Hag shop in Griffin, would be my destination, for an inframe.

[tree98]

Infame it..... a million miles is really all you should ask out of an ISX or you risk catastrophic damage.

BUT it must be rebuilt properly. All OEM internals no aftermarket, the counterbores absolutely have to be cut and the liners shimmed up to .014

the head must be replaced with brand new OEM not a reworked or rebuilt one. It also must be torqued down properly by doing the initial torque and then letting it sit overnight for the gasket to crush and then doing final torque.

All the proper steps are in Rawze's rebuild series on YouTube.

I'm curious if this engine is still mandated or has it been tuned? I'm also curious if anyone has ever rebuilt the high pressure fuel pump? Those have to be rebuilt every 400k miles or you risk complete engine destroying damage, we're talkin boat anchor type stuff.

[Rawze]

ISX's have shorter rods and very different compression ratio, very different components,. and very different designs, even in how they are programmed and how they run. They are thru, a very, very, VERY different engine all together compared to the old yeller you had there, so forget everything you thought you knew. None of it applies.

ISX's are actually a good engine, but a person has to care for them properly. THIS MEANS NOT NEGLECTING AND ABUSING THEM! .. or you get exactly all of the nightmares about them not lasting very long, and all of the other issues that people say about them. The bulk of people who own trucks these days neglect, abuse, and shove bad custom tuning./delete programs in them due to sheer ignorance and then always blame all results of this abuse on the engine. It is the norm, not the exception.

Learn to care for it properly. Have it rebuilt 100% properly (rare to find anyone who will do this any more)... and if it is in fact, de-mandated(deleted).. then just like preventing sand in your oil .. Only use a program that has been 100% vetted, reviewed, etc. by myself (Rawze) at some point to ensure nothing in it will harm the engine long term. 90%+ of all programming that I review every year is absolutely harmful to these modern engines and is an absolute plague in the trucking industry.

Does not matter the engine has a lot of miles on it .. if the engine/truck is in fact de-mandated (deleted), then that is top priority to have the programming reviewed for safety. copy the program out of the ecm and e-mail it to me for a proper review of what someone did, good, bad, or downright ugly.

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replying to your post...

(02-01-2023 )dccustomfarms Wrote:  ... a million miles and 30k hours on the clock....

Previous owner stated that the head, or the pan has never been off.
...

What you mentioned above is a form of neglect all in itself. The rod/main bearings should have been done at the 800k mark if someone wanted it to make it past a million miles with it.

Since it was not done, it is now a ticking time bomb, waiting to put a piston thru the block with zero warning at this point. Not doing the rod/main bearings at 800k sets it up for accelerated wrist pin wear, and eventual wrist pin failure. Doing it now at a million+ will not make it any better if this wrist pin wear has already starting setting in.

Is it time to inframe it.,.. and like others have said.. it has to be done right, and hardly any one any more does them right. Hence all the ignorance-based horror stories about how they do not last very long.

Here is how it needs to be done... Any shortcuts and it will not last another million...
ref: http://rawze.com/forums/showthread.php?t...6#pid70606

you also did not mention what rear end ratio the truck has. If it has tall gears, this = engine abuse due to it lugging its whole damn life with some complete fool trying to climb every damn hill they see with it below 1500 rpm.

Red engines are not yellow engines. They need to be driven ABOVE 1500+ (1500 - 1900) rpm range when under any kind of heavy load to retain the longest engine life and reduce wear.

[dccustomfarms]

Thanks everyone for the information.

The truck is still fully mandated. Nothing has been removed or tuned. I was told the DPF has been replaced once and that's all. Not sure on the high-pressure pump.

Also, the truck has 336 rears behind an 18 speed.

I am leaning towards putting it in my shop and doing the rebuild. I have to get the cummins counter bore tool in order to do the mid stop. Mine is only set up to do the deck on caterpillars. Does anyone have a list of shim options for Cummins? I have the list and part numbers for cat only. What is spec for protrusion on the isx, and does the isx use a spacer plate?

As I start this process, I am sure that I will have many questions. I appreciate everyone's input.

[Rawze]

(02-02-2023 )dccustomfarms Wrote:  Thanks everyone for the information.

The truck is still fully mandated. Nothing has been removed or tuned. I was told the DPF has been replaced once and that's all. Not sure on the high-pressure pump.

Also, the truck has 336 rears behind an 18 speed.

I am leaning towards putting it in my shop and doing the rebuild. I have to get the cummins counter bore tool in order to do the mid stop. Mine is only set up to do the deck on caterpillars. Does anyone have a list of shim options for Cummins? I have the list and part numbers for cat only. What is spec for protrusion on the isx, and does the isx use a spacer plate?

As I start this process, I am sure that I will have many questions. I appreciate everyone's input.

with 336 rears, it is not set up for freight very well unless you hauling nothing but air. You need to start looking into replacing those rears with some thing better. What gear ratio it will need will depend on what you are hauling and how heavy. A set of 3.79's are ideal for 80k freight, 4.11's or deeper if your hauling heavier than this.

as far as specs go, use the cummins hardened brass shims for them 0.020" oem shims are the standard to use on a first inframe. here are the numbers...
ref: http://rawze.com/forums/showthread.php?t...9#pid28349

lastly, it being a square-brick that belongs in a museum .. when driven on the highways, driving it above about 63~ish is noting but costing you fuel like a pig. This means that learning to drive it at lower speeds (and higher rpm ranges when pulling) is the key to success with that thing in today's low-margin, high fuel price market.

[Waterloo]

I have 3:42's in mine, with the 18 speed, but I drive it as Rawze stated above, keep the RPMs up, speed down. I haul lite freight in a box, heavy for me is 15,000 pounds, and I rarely leave Michigan. Ohio is a foreign land... The 18 speed is probably what has saved that motor, and the gentleman driving it. I would in frame it, and keep an eye on that pump. New damper too... Cummins says 500,000 miles and change them out. ;-)

And only use OEM parts, do not cut corners.