hello all. first post here. my 04 spun a rod bearing the other day out of no where. question is i have the pan off and took the rod off and the crank seems ok. its a little grooved up but not bad at all. i played with it a little bit and it seems with some very fine emory cloth i could clean it up pretty well. anyone think i would be ok cleaning it up and putting a new bearing on and go with it. not sure why it spun. oil is changed regulary and truck is 100% stock with 120 k on it. any ideas on this. btw i blew brake clean and air through the passages on the crank and theres no obstruction so the bearing was getting oil. thanks

 

if that surface sees any movement across it, it has to be perfect. imho "sanding" it is not quite up to perfect. what you do is up to you, but if I were driving it after all that work, i would want it right. welcome to the site btw, enjoy it.

 

There is a reason the rod bearing spun. A quick clean up may work but then again it may not. I have a company that has 25 or so trucks on the road. (Mostly Macks) And we have done between the rail rebuilds plenty of times and in just about every case we have had no problems. Once in a while we have had to pull the engine. I melted a piston in my 03 and we just cleaned up the cylinder and fired some new bearings in it and 80,000 miles later she's still going strong. If you don't mind going back in if you spin another bearing clean it up and run it. Thing is if you spin another bearing it may cost you a bunch more money. (I have some pics if you want to compare)
Good luck,
Topper

 

As Topper said, there is a reason the bearing spun. A new one will do the same if there is a problem getting oil to it or something. Also, sanding the journal is only OK for very minor scratches or discoloration, and it is done best with the crank out where you can spin it or use a long piece of emery cloth to do it evenly. It's unlikely you'll get good service from throwing another bearing in and sanding it a bit. Once the bearing has failed bad enough to hear it knocking and you see journal damage, you need to turn it and go to an undersized bearing, or get another crank, and find the original cause.

 

topper, pics would be great. my understanding is the crank journal gets its oil through the next main pickup. i blew air and brake clean through the oil holes and all seemed good. even compared it to another journal . not sure why it would spin

 

Hey 007,
I looked and I have lots of pics of broken stuff like pistons and trans parts but all I could find was this 1 pic that kinda shows the crank. Look good the surface of the crank looks pretty good. If you have scratches like the grooves on a record I would say it's time to head to the machine shop.
Topper

 

if it has a grove then it is time to turn it. i think you would be wasting your time if you sand it down and slap in a new bearing. as said earlier you would more than likely do more damage the second time around.good luck with it

 

The problem with spinning a bearing is that it shreds the bearing into gazillions of small chunks. Those manage to get through the rest of the engine and do a lot of damage. After trauma like that you need to take the engine apart and clean. A lot of the parts can probably be re-used, though. But you'll have to replace things like oil pumps and lifters.

The last time I spun a rod bearing (gas engine), the bottom of my oil pan looked like this:

 

OH NO .boB.....

You got those Colorado Metal termites!!!