Diesel fuel is hygroscopic... it will absorb water.
I owned a diesel Mercedes for quite a while in SoCal.
I learned a lot about that little 4 cylinder engine.
I added a quart of ATF about every 4th tank of fuel.
ATF acts like a cylinder and injection cleaner, really reduces diesel pinging.
On a vacation at very low temps, one morning it would not start.
Had to use starting fluid. Got it to a Mercedes dealer and had the glow plugs replaced.
I'd drain the fuel tank, put in new diesel fuel.
Try starting fluid if it still doesn't start.
Gnarls.
