Knock in Engine?

[joleary223]

I know diesels make some noise, but I have a problem. I have talked with a couple of shops and got the same answer twice. Crankshaft slap. When my 96 7.3L f250 is in gear (automatic) at a stoplight or something, it has a rythmic knock. Aparently the crank is sliding back and forth at idle the sound goes away when I am at speed. The mechanics said I should just wait until it dies because the repairs will be expensive one way or the other. They suggested just wait and buy a new engine when the time comes, I will save on labor that way. I have been told the truck might hang on for years so I drive and wait. I am currently saving up the the 4 to 6 thousand dollars I will need. I like this truck and I paid cash for it, so puting a new engine in it is way cheaper than a new truck. Has anyone ever heard of this before? Can I still put some mods on the truck to get more power for towing. I tow a 8500 pound camper on occasion. I don't care about speed the truck will run off with the camper now. Any Ideas or suggestions would be helpful.

[SCUFFY828]

crankshaft slap is a totaly new phrase to me , without hearing noise would be impossible to diagnose

[joleary223]

When the Mechanics diagnosed the problem they had me put the truck in gear and put the emergency brake on. They crawled under the truck to listed to the noise, it's comming from the bottom of the engine, I jumped in and out of the truck and they said they could here the crank sliding around ( the knock changed when I jumped in and out). Sometimes the truck sounds normal if I put it in neutral at stop lights other times it starts knocking. The first place I went to thought it was a collapsed injector but the truck passed every test the computer could produce. I had never heard a diesel make the noised this one did when it was going through the computer tests! After they ruled out the injectors they gave me the crank opinion. The truck seems to drive fine and tows well.

[ABOBB]

Scott.. I'm not the expert here.. but it sounds to me like the mechanics he is dealing with are telling him that the thrust is going out of his crank. Sounds like they are describing the crankshaft knocking, by moving forward and aft.

Don't know if that's possible.. and really wouldn't think it would be major expensive to fix (new set of bearings??).

[SCUFFY828]

i agree that it is very possible to have a crankshaft move back and forth and have some crankshaft end play due to possible worn thrust bearing , but moving enough to knock and not have a problem , im not sure

[BlackCloudStroker]

also i have noticed that with the new ultra low sulfer diesel there is alot more injector knock, if you you add additive to it it goes away, so im guessing that the lowersulfer diesel isnt keeping things lubercated very well. Just what i have notice kinda sounds like spark knock in leaded motors running unleaded fuel with additive. just my two cents.

[joleary223]

I tried additives. I use amsoil, I put a whole bottle in for two fill-ups with no change in the knocking. Now I use the suggested amount. I don't think I have any injector problems. The thrust bearing seems to ring a bell. That might be what the mechanics said was the problem. They seemed to think that if they open up the engine, with labor and any other problems they might find, in the long run I would be better off with a crate engine.

[BlackCloudStroker]

You could always cut open the oil filter and see if you are getting any metel flakes. If you are i would say its time to do some thing.

[joleary223]

Originally Posted by BlackCloudStroker

You could always cut open the oil filter and see if you are getting any metel flakes. If you are i would say its time to do some thing.

Roger That! I'm due. Should I just put the drained filter in a vise and use the sawzall?

[Performance Oil Products]

I wouldn't just cut a filter open, get a blackstone they can tell you everything going on with your engine. If it's bad i wouldn't spend that much to get it fixed get an engine.

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