95 f350 piston cooling jet broke off

robp823 · March 20, 2011

Doing an oil pan on a 95 f350 and found a piece of the cylinder #2 piston cooling jet in the pick up screen.It left 4 good punch marks in the bottom of the piston.I grabbed the rod and tried shaking it checking for play and it was tight.Cylinder wall looks good.Bottom of the piston isnt black like i thought it would be.The wrist pin is a little diffrent color than the rest.The only thing i can think of is i found a can of starting fluid sitting on the front seat.Any thoughts on what could have caused this???Should i replace the jet or will the piston just crack it off again.I dont know how critical it is on 7.3's with the piston cooling jets but i do know on CAT if that piston cooling jet is just a little bit off or gone your going to smoke a piston.

Jim Warman · March 20, 2011

Over the years, I've come across the odd piston cooling jet laying in the bottom of a 7.3 oil pan... truth be known, when changing oil on one of these, the smart money will be on rapping the bottom of the pan with a rubber mallet and listening for the tell tale sound of something bouncing on the pan floor...

As for what causes the cooling jet to change locations... I think "shit happens" about sums it up.... if your piston is hitting the jet - you have a lot more problems than you needed and it might be time to start checking for a bent rod.

As for how necessary the jet is... if the truck is idling or being driven lightly, you don't even need the piston cooling effect... Start driving hard and getting the combustion chamber temps up - say, when towing a trailer or heavily loaded - the need for the extra cooling increases...

robp823 · March 21, 2011

hmmmmmm bent rod would make sense.the starting fluid would def cause that.Its a dump truck and they beat the hell out of it towing and usually overloading it.Also plowing.I looked at the front end of this thing and both front shackles were broken right off and the springs were sitting on the frame.The cooling jet was actually lodged in the screen of the pick up.Im just wandering if im wasting my time putting a new one in if its just gonna be broken right off again.I guess i could put one in and turn the engine over by hand and have someone watch for me then go from there.Thanks Jim