Strange glazing on tank vent hose

[EmeraldCoastSailor]

My boat is 9 years old and in the last 6-9 months it has developed a tiny leak where the vent hose connects to the tank. Of course a small amount of fuel rests in the vent line when I fill the tank. It runs into the tank once a bit of fuel is consumed via running the engine but given my circumstances this might take a week or more, especially if I fill up upon returning to the marina.

The glazing is on the inside of the hose; hopefully the attached photo helps. Has anybody heard of diesel crystallizing or glazing up? I think it is this glazing that is making the 2 clamps holding it to the tank vent nipple not as effective as they should be. Thoughts?

[a64pilot]

I bet some form of "bugs" you know, the stuff that grows in a fuel water interface

[Wotname]

Originally Posted by a64pilot

I bet some form of "bugs" you know, the stuff that grows in a fuel water interface

+1

I'd replace the hose.

[rognvald]

There is no possible damage to your fuel system that can occur from the minimal glazing at the end of your vent hose as it appears in the photo. Unless the hose appears to be degrading, clean out the end that abuts to your vent nipple and retorque it properly. If you are using a diesel fuel conditioner and clean fuel filters, there will be no net effect to your fuel system. Good luck and safe sailing.

[mitiempo]

As fuel remains in the vent hose for a while after filling the tank make sure the correct hose is used. Best choice is A-1 fuel hose, which is not in any way degraded by fuel.

[jacktheflyer]

I have come across a winterizing agent in the past that was added to diesel to improve the flow properties in cold weather. I have had this additive precipitate and clog filters where the diesel has been bought in winter and stored over a couple of seasons. This was in bulk tanks (35kl) but have never heard of it happening in a small engine tank.

Scrubby