Fuel getting into the oil
 

Hi...
Yesterday my husband was driving to work, 1997 Ford F 350, the engine started making a bad knocking sound, like he had thrown a rod, running really rough, and lots of smoke coming out the exhaust. Once we towed the truck home he check the oil and it was too full and smelled like diesel fuel. So it looks like somehow fuel is leaking into the oil. Once he drained the oil, the truck started up fine and no more knocking sound.

Any ideas on what could be causing the fuel to leak into the oil? He was thinking that it could be a bad injector or maybe the fuel pump but was not really sure.

He keeps the truck very well maintained and changes all the fluids regularly.

Thanks for your help!

Could possibly be bad injector o rings. Someone else will chime in shortly though

Check and make sure that you have not lost radiator fluid and then repost

The radiator fluid was fine, he checked that last night.

Thanks again for the help!!

A few more Q's
 

Has there been any recent maintenance?

Was the truck sitting for a extended period of time?

Is the wait to start light flashing?

Do you have a code reader?

High oil level will cause foaming and running issues as described.

Its very abnormal for fuel to get into the oil unless the cylinder hydrolocks, hydrolock is normally found during injector replacement.