Diesel Fuel Leak?

[RLCASC]

Left storage before last trip, wife noticed a small dark spot on ground about where left front of fuel tank would be located. I looked under MH and saw 1 small drip on front fuel tank strap. Wiped drip and waited no other formed. Upon returning to storage, I placed a pan under the left front corner of fuel tank where I had seen the drip. Went back 1 week later to check on contents of pan, approximately 1/2 cup fuel in pan.
Before taking MH to local Freightliner dealer, does anyone have any insight as to where such a slow leak could originate from.
I do keep fuel tank full, and even though MH is under cover, and out of the Sun, could fuel expansion be a cause. Thanks for your input

[Jim_HiTek]

Most RV tanks have a couple hoses on the top of the tank. Those can age out and start leaking. Your rig is 11-12 years old and it wouldn't hurt to inspect them.

If it's determined that the hose has aged out or has a hole worn into it, note that usually you need to drop the tank around 12" to access so it can be replaced. An afternoon job from what I hear. Using a floor jack.

It's just bad luck because many of those hoses last for 20 or more years.

[Ray,IN]

The expansion question might have merit. Is there a flexible connection in the fill neck?