M-9000, extra "ping" from engine.

I know, diagnosing a sound being described from a guy on a forum is pretty far fetched! But, I'm willing to give it a shot. ... My 9000 was overheated by the operator earlier this summer (never blew out the radiator when mowing). Ever since then it has had a "ping" from the engine. It's not a compression sound, like a diesel should sound like. I've flushed the coolant, been through two oil changes, and replaced the water pump- it failed about 200 hours after the "noise" started, and checked all valve clearances. The tractor runs fine, no loss of power, no milky oil and the antifreeze looks new still. I ran my borescope to the intake valves that I could get to and the valve stems do have some carbon chunks on them, but nothing I wouldnt expect. The ping is most noticeable at idle, then the natural noise of the engine drowns it out.
My thinking is that I may have an injector failing. I should say that I hope it's an injector . After that I'm pulling the head, the tractor wont move untill next spring anyways.
 

MBDiagMan

E-5, US Army 1968 to 1971
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With engine idling, crack open the lines at the injectors just enough to dribble fuel and cancel fuel pressure, one cylinder at a time. Listen for a change in the sound. If the sound goes away when cracking an injector line, then that cylinder should be the culprit.

If you do find an offending cylinder, swap that injector with a neighboring cylinder and repeat the test to see if the noise follows the injector. I don't expect it to, but if it does, replace the injector or just forget about it and live with it. If the sound stays with the cylinder, then you have a problem in that cylinder.

If it does turn out to be a problem in the cylinder and it is running fine, then the nature and severity of the noise should determine whether or not you take it apart.

Noises are VERY hard to help with over the internet.

Hope this helps
 
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