Z655 Hydros

/ Z655 Hydros #1  

feetr2c

Member
Joined
Jun 3, 2014
Messages
35
Of what importance is the little foam plug under the cap of the hydro expansion tank/reservoir?

Also, the manual says that if the level in the reservoir is too low, to add 10W-30 motor oil???
 
/ Z655 Hydros #2  
The foam piece is a vent/breather device to allow hot, expanded air/gas to escape. There are a lot of full commercial grade ZTR's that use 20W-50 motor oil, so that is not surprising at all.
 
/ Z655 Hydros
  • Thread Starter
#3  
So I assume that that must mean that the plastic screw caps do not seal the reservoir? They are only there to keep debris out and hold the foam filters in place?

On another note, the "full" mark is literally like 1/4" off the bottom of the reservoirs. This makes it difficult to see, and the left one especially is dang near impossible to see the bottom of the reservoir. After a couple hours of mowing, expansion has raised the level by just a little, maybe another quarter inch or so, but still tricky to see. Can't I just dump oil into them so the reservoirs are like half full? That would make it easy to check with a quick glance, and since expansion is so little, there would be no risk of overflow. I mean it's just an expansion tank. I see it like the coolant jug on an automobile. If you have a little bit in the bottom it's fine, but if you "overfill" it, it won't hurt a thing. It's not like overfilling a crankcase which has no reservoir.
 
/ Z655 Hydros #4  
There should also be some sort of rubber O ring as well as the foam to act as the sealant.
I'd follow what your manual says to do. With JD equipment, they usually tell you how to do things/things should be for a very good reason.
 

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