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View Full Version : John deere 6068 piston problem



rick
01-27-2004, 10:53 PM
I cracked a piston at 2100 hrs and cracked 5 at 4200 hrs the only piston not cracked was the one replaced at 2100 hrs anyone know of similar problems with this engine any info appreciated

M.Murphy
10-21-2006, 01:44 PM
"My 6068SFM s have done 50 hours and both intercooler casings have cracked , anyone had this happen."

Capt William Myers
01-29-2007, 11:25 PM
"A cracked piston is an unsual occurrance but to have several can only mean a design problem, or metal casing problems, if this is a newer engine I would contact the dealer first and then take my case to the John Deere seeking relief for the cost of the repairs. I have repaired engines for 40 years and usually a cracked piston is due to hydro locking or a dropped valve. If made right they should last the life of the engine and a rebuild or two. Good luck, keep us informed."

Lanny Dellinger
03-18-2007, 08:54 AM
"I have a new 6081 330hp and it does not want to run at the proper temp unless I am at cruising speed (1800 rpm. Once I slow down or let it idle for a miniute it drops down to a temp of 130. The thermostats have been replaced and they all react the same way. The replacements are identical to the factorys, they are strange as they seem like they are designed to let some coolant by at all times even when they are closed. I have spoke to several other owners and they all have the same thing going on. I thought thermostats were supose to keep an engine at the proper temp regardless of engine speed? Any suggestions."

eldon
05-23-2008, 02:16 AM
"Engine oil keeps getting inor my coolant or expansion tank (6068t). I replaced the oil cooler. However, the problem keeps coming back."

goldrush
07-08-2011, 09:29 AM
Is this thread still valid? If so, I would like to gather more info. I have now had failure in both of my 6068TFMs with cracked pistons, and I think I have a lot in common with the 5 cracked old piston not the new one scenario.

Any info would be helpful

Thanks,

Kevin

portengineers
09-27-2011, 12:03 PM
sounds like a head gasket

portengineers
09-27-2011, 12:04 PM
the boat may not be proped rite and or the injection timing may be off

alexgrill
11-24-2011, 06:51 AM
You must have to take care of the piston i think you have to replace it..

alexgrill
11-24-2011, 06:53 AM
You must have to take care of the boat and its parts in the long journey it will be big problem, i think you have to change the piston..