Knock Knock on shutdown - 02 Bobcat S185

[paoutdoorsman]

New to me Bobcat S185. Everytime I shut it down, the engine stops and it is immediately followed by a clunk clunk. Very consistent. Everything seems to work perfectly normal otherwise. Anyone else heard this or know if it is cause for concern?

 

[Bswwood]

Might be the fan gear box. Look and see if you have a belt drive fan, if you do you probably have slop in the fan drive gear box and when you shut the machine down the fan bounces back and forth and sounds like the engine knocking.

 

[Tazza]

Might be the fan gear box. Look and see if you have a belt drive fan, if you do you probably have slop in the fan drive gear box and when you shut the machine down the fan bounces back and forth and sounds like the engine knocking.

I have heard this sound too, it was my fan and belt/tensioner. As the tensioning system is done with a spring loaded tensioner, you shut down and it kinda hammers, nothing to be concerned about if it is indeed what is causing it.

 

[paoutdoorsman]

Might be the fan gear box. Look and see if you have a belt drive fan, if you do you probably have slop in the fan drive gear box and when you shut the machine down the fan bounces back and forth and sounds like the engine knocking.

Thanks for the replies! It does look like I have a belt drive fan. I had someone shut down the machine while I watched the belt drive and tensioner. It looked like the fan drive gearbox pulley was the source of the noise, so I pulled the belt off. There is some very minor play/movement in the gearbox or pulley and if I roll it back and forward by hand I get the same noise. Can this play be taken out or is it internal wear that can only be addressed by replacing the gear box?

 

[Bswwood]

Thanks for the replies! It does look like I have a belt drive fan. I had someone shut down the machine while I watched the belt drive and tensioner. It looked like the fan drive gearbox pulley was the source of the noise, so I pulled the belt off. There is some very minor play/movement in the gearbox or pulley and if I roll it back and forward by hand I get the same noise. Can this play be taken out or is it internal wear that can only be addressed by replacing the gear box?

There is a plug on the front of the gear box to check the oil, if its low add some oil and see if that helps.

 

[paoutdoorsman]

There is a plug on the front of the gear box to check the oil, if its low add some oil and see if that helps.

I did see a plug on it. Does it use gear oil?

 

[Bswwood]

I did see a plug on it. Does it use gear oil?

Gear oil will be fine, 80w90.