Slowly losing coolant

[SunnyJim]

I'm slowly losing coolant from the overflow tanks cap. The tank is not overly full if anything it is nearing the bottom now. The engine has never run hot or over heated but the cap clearly has coolant on the outside of it and it drips down onto the engine and injection pump.

Any ideas? If I replace the cap will it solve the problem? I've never seen a tank do this.

 

[Matt_Jr]

Can you post any pictures. I'm unfamiliar with your tractor, but working on cars I've seen imperfections in radiators and overflows that required a little filing or sanding. I've also seen cracks.

 

[art]

IF it's not showing on the outside components of the cooling system then it has to be going inside! This could be a cracked forging or a leaky gasket.

 

[Highbeam]

Mine has always blubbered a bit of funk onto the top of the overflow tank. When I bought the machine it was at the full mark and over 850 hours I've only had to add once when the low coolant light came on due to low level in the res. I don't know if it is steam or what but the top of that res always has some junk on it from a leaky cap.

Note that the reservoir is not pressurized. It's just a push on cap with a hose that should release the funk lower but doesn't work too well.