F3680 pinging sound

[Jawjadawg]

New member here. The zero turn listed above with a diesel engine just started making a pinging sound yesterday. The blades became wedged and I tried a couple times to get it to free on its own but it would only start to bog down. I was probably cutting stuff I shouldn’t have with this mower. I have a couple decent sized patches of Johnson grass I’m trying to keep from going to seed. In total they might equal 2 acres total and I preferred the maneuverability of the mower to my tractor and bushhog. I drove up to my shop and it started pinging. I turned it off for a few minutes and it didn’t ping when I cranked it again until after about 15 seconds of running. Today I cranked it up and ran it a few minutes at idle and it didn’t make the sound from a cold start. I’ve uploaded a video to YouTube. Next steps?

Kubota V1505 D22 Combustion knocking or mechanical?

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Thanks for any feedback!

 

[North Idaho Wolfman]

First an F is not a zero turn, it's way more than that!
An F is a reverse tractor.
And second you have a serious mechanical issue!
I'm going with a spun rod bearing.
Stop running it till you fix it.
I would first start with a compression test.
Turn the engine by hand and see if you hear any noise.
You might need to remove the injectors or glow plugs to release compression.

 

[Jawjadawg]

Here is how it sounded today from a cold start. Would a spun rod bearing sound different from a cold start?

July 4, 2026

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[North Idaho Wolfman]

Here is how it sounded today from a cold start. Would a spun rod bearing sound different from a cold start?

July 4, 2026

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Yes cold oil, could make a difference in sound.
Just keep running it, and soon the parts inside will be the parts outside!
Makes it way easier to inspect the failed parts.

Granted making a complete assessment of the issue via a couple videos, 3000+ miles away would be pure luck.
Assessing it via the tests I suggested would be better path.