My X720 did it and my X748 does it , don't know where it goes, no leaks no sloshing.
not in the oil, not in the coolant.
It seems to stabilize a little when it gets down about 2" below the max mark on
the tank.
The hose and grommet on top of the overflow tank was upgraded a couple of years
ago to stop coolant from leaking out around the grommet, but mine have this , as I
said no leaks, just thirsty i guess.

Jim

 

There has been a couple threads on it. It is normal. If you fill it up to the max line it will slosh around and come out the over flow. I keep mine about 2" below the max line and have no problem.

 

http://www.mytractorforum.com/showthread.php?t=256095

 

I've also seen them tend to be happy just below the ADD mark. As long are there is coolant in the bottle, you are fine (the radiator is full if you see that).

Don't sweat it.

 

Mine sits right about the Add Mark. It has been there for about 200 hours now. When I shared this picture as part of a thread on maintenance, several people commented on it.

 

I figured out about the first year we had ours, that the SLOSH factor is something to not worry about. In the summer, when I'm mowing, it sloshes out the overflow. All other times, it doesn't leak a drop.

 

Wow, that is a clean engine.

 

That picture was taken after a clean up and during the major annual maintenance. It doesn't look like that most of the time.

 

My engine never stays at the full mark. The coolant drops below full and stabilizes. As long as there is coolant in the reservoir and there are no obvious leaks, I wouldn't worry about it.

 

My X728 dosen't stay full either, haven't worried about it, I have a warranty...

 

I have the X728 model year 2012 with the coolant disappearing problem. Added coolant twice in the first 25 hours of use. No leaks found. Radiator is full and doesn't run hot so I don't worry about it.

 

I'm reviving this old thread about disappearing coolant in the x700 series gas powered garden tractors becasue I think that I have found the source of the problem.

I had the same problem for months until I finally broke down and bought a good cooling system pressure tester. When I first attached the tester to the JD radiator I found that the system did not hold pressure because air was leaking out around the radiator spout seal where the tool attached to the radiator. I cleaned the spout good and wiggled the tool attachment until there was no leak and the system then held ~10 lbs of pressure just fine.


I then cleaned the rubber seal on the radiator cap, installed the cap and I don't lose coolant anymore. I think that the coolant was leaving the system as steam through the leaky cap seal. I know that this is a little unusual but it has been months since I have added coolant to a machine that needed to be topped off after every use.

Mike.