Tapping Sound on My Kubota L3902 HST

[Alex001wong]

I'm dealing with a funky issue on my Kubota L3902 HST. There’s this weird tapping sound coming from the engine, esp. when it’s cold during startup. It disappears once the engine warms up, but it's still concerning.

Anyone else run into this, or have any idea what might be causing it? I’m just hoping it’s not something major.
Thanks!

 

[lilman2019]

Sounds like it might be some slop in the solid lifters, maybe a quick valve adjustment will do the trick!

Also, you might wanna check if you’ve overfilled the oil too... just brainstorming some possibilities here!

 

[prestigious-iceberg77]

Cold start tapping that fades with heat is often tied to valve lash but on the L3902 HST, there have also been reports of injector knock when fuel quality is marginal, so check both before assuming it’s only lifters. Have you noticed if the tapping changes with throttle position during warm up or is it steady until the engine reaches temp?

 

[Apric0t]

I'm dealing with a funky issue on my Kubota L3902 HST. There’s this weird tapping sound coming from the engine, esp. when it’s cold during startup. It disappears once the engine warms up, but it's still concerning.

Anyone else run into this, or have any idea what might be causing it? I’m just hoping it’s not something major.
Thanks!

you know, tapping that disappears when warm can also be a sign that the engine is not firing cleanly on all cylinders for the first 30 seconds. This could be a slightly weak glow plug or a sticky injector, causing the combustion to be unbalanced and louder.
Try running a quality diesel fuel system cleaner through a couple of tanks. If the issue is a slightly dirty injector tip, the cleaner can often smooth out the combustion noise.
If that doesn't work, test your glow plugs for continuity