New PSD owner needs some help

[cjnspecial]

Just bought 99 f350 w/248K miles in excellent shape inside/out, doesn't smoke or leak oil, starts easily and idles great however.....the engine makes a knocking noise and there is a little bit of oil in the coolant. Previous owner said he just changed the oil cooler o-rings and it's probably just some residual oil....hopefully that is the case. There is no coolant in the oil.
About the knock..it's tough to pick it out from the normal diesel noise but is clear as a bell when decelerating in any gear between 1800-1100 rpm. It sounds like a cracked flywheel but the flywheel is not cracked and all the TQ bolts are tight. I also checked for play in the turbo shaft bearings and there is none, the fins have no visable wear either. I rode in my neighbors f250 and when he lets off the accelerator the engine is just about silent for a few seconds. Can anyone point me in the direction of what could be causing the knock?

[SMKSTAX]

WELCOME TO THE ORG!!

[cjnspecial]

Had a ford mech check it out and he said it was piston slap and not to worry about it....Said a lot of trucks are noisy like that and it wasn't hurting anything.
I always thought piston slap was a very bad thing.

[Deeslfxr]

Originally Posted by cjnspecial

Had a ford mech check it out and

Did you get that in writing?

I would have to agree.

[Ryan Rønning]

You need to go get a second opinion!

[cjnspecial]

I'm with you guys, I just wan't to know what is causing the knock so I can get it serviced, if needed, before it flies apart. I'm going to get an oil analysis and am trying to find a good powerstroke mechanic. If any of you guys know a good mechanic around baton rouge or lafayette,LA shoot me a PM.