Injectors

[Rawze]

My engine has never been abused, nor has ever suffered reflected heat damage to the injectors due to clogging exhaust components and failing DPF cans.

I changed the back 3 at 950k miles when i did my inframe just because one of them got a very large leak, made a lot of bubbles on a test and engine started to surge sometimes.

I have small bubbles on my front bank, too small to find when turning by hand. The injectors have more than a million miles on them now. The engine sometimes runs slightly rough too but truck is still breaking 8-9 mpg. I am NOT going to change them until they start to cost me money in lost fuel mileage or they start to fail enough to find when turning by hand.

My own take on it is that a perfectly smooth running engine is nice to listen to, but do they make you any more money than one with worn components? -- Usually not, unless it becomes bad enough to make the engine have unstable operation and/or starts effecting your fuel mileage in a measurable way.

For my own truck, I will change my front 3 if my fuel mileage drops and I see the bubbles easily when turning the motor by hand. Until then, I will not waste money on them.
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Slightly rough running engine can be many things. Engine running moderately rough, something should likely be done about it, and very rough running engine will definitely cost you extra money to operate. With a million+ miles on it, if it has not been in-framed yet, you should have, or have saved enough money for to inframe it, or have that established plan in place, waiting for that day it gives up the goat. It would be poor business planning not to have this in place.

Just some words of wisdom ...

If you have not done so, At 1 million miles on it,.. pulling injectors that are leaky and replacing them if needed should also be accompanied with a LOT of other tests, and pulling/replacing rod/main bearings, boroscoping the engine, and finding out really what you have, and how worn it is overall. that way you can start planning on what to do with it to restore it, or replace it. -- I.E. -- no matter what you do -- S#$#T don't last forever. - Otherwise, you are only fooling yourself. - Would I change all 6? -- Myself, probably not, unless I saw evidence or cause to do so. I would change a leaky one, but I would start to focus on the metering and timing actuators first if they are that old too. Getting an engine that old running nice and smooth again will likely require both injectors AND actuators at the very least.