When do you do Rods and Mains? How about inframe?

Most guys that I know don't touch them until the oil samples show the need, unless you have to crack things open for something else. Then I'd slip a set in while it was apart. The truck I just sold had 800K on it and had never been touched and the samples were still good. That was in a carhauler with the higher duty cycle that goes along with that, plus the idle time while loading.

 

I'd heard bearing failure was associated with fuel dilution, more of a problem with older engines. Higher levels of wear metals in an oil sample would indicate this.

 

To me just swapping out bearings is a half a fix but it will extend the life but not near like a complete rebuild. The crank side wears too and sometimes like an egg. For a proper rebuild the crank needs turned and oversized bearings used. Then comes the question of rings and cylinder walls.

I'm like hammer drive her till it's time and do a complete rebuild.

 

If i bought it id run it at 15k-20k per oil change and pull a oil sample at either every one or every other to get a baseline over 2-3 samples then go from there, u start throwing $ at stuff that dont need done yet you'll have other stuff actually needin fixed, best to fix what actually needs it vs fixin when it aint time yet

my bearings got 900k on em and samples show hardly any wear at all, so the hammer stays down till i see otherwise

also watch ur oil pressure, u start havin alot of fluctuation up and down in oil pressure 8-10 psi also i sign they're wore, but then u should also see the correlation in the sample

 

This is the wrong place to ask that question, But any way your thinking is pretty close but talk to a shop that changes them regularly and ask them to get a feel of what to do but it never hurts to do them, it not much money for the piece of mind, I remember the N-14 if you didn't keep good bearings in them you could destroy a perfectly motor............

 

I always recomend a bearing roll in at 250,000 miles and every 350,000 after that, bearings are cheap, If you pay for the oil samples save your money and just change the bearings. Clean out the air filter housing and if it hangs on the cab use solvent to test it for leaks, every time you touch the filter.
You can get the engine history from Cat of most any truck dealership. The warrenty history will give you the dealership it was worked on at that might give you the service history for a phone call.
Just a thought!

 

Complete waste of money. Changing bearings every 3,4, or 500k will only buy you peace of mind. Bearing rolls as part of regular maintenance was the norm up until about 15 years ago. Today, bearings are good for the life of the engine. You would replace them at overhaul time, or like mentioned, fuel dilution or some other problem. I can understand if you are buying a used truck and just want to make sure, but if that is your mentality, you might as well replace everything to be sure. If you need bearings after 350k something is greatly wrong with your servicing. Bearings are not cheap and takes a full day's labor to do. Pulled many down that didn't need changing. Save the money for your overhaul, when it is needed.

 

If an engine is putting out a lot of HP it can take it's toll on the rod bearings. I've seen bearings look good at 500,000, but if I was buying a truck and wasn't sure, I would at least drop the caps and look, nothing but labor and oil pan gasket. I have never seen or heard of a crankshaft wearing from normal wear, they're harder than Chinese arithmatic, and the bearings are made softer for a reason, but I've seen several scared from a bad bearing.