Beneteau fuel tank diesel odor

[Boyd18185]

I have a 2002 French-built Beneteau 42 CC Oceanis Clipper. For the last 3-4 years, diesel fuel odor has become stronger and stronger, and yet we can find no leaks or spill anywhere. So...we have come to suspect the fuel tank, which, according to the recycling label of 4 is made of low-density polyethylene (LDPE). According to references I have consulted LDPE is unsuited for use as a fuel tank. Instead high-density, cross-linked polyethylene (PEX) is required. The tank manufacturer responded to an inquiry that they use a plastic of density 0.938kg/m3, which they claim is equivalent to HDPE. But apparently it is not, since every source I've consulted said 0.94 is the lower limit for HDPE.

All that said, I'm wondering if there are other owners of French-built Beneteaus who have encountered fuel tanks whose walls seem to be permeated by diesel fumes. This is not a trivial issue, because the odor is almost unbearable the first day aboard, despite the fact that we have solar-powered vent fans on the boat. Once we solve the odor source, then we will try to rid the interior of the residual odor.

Any insights would be appreciated.

 

[jschroeter]

I had a Beneteau Oceanis 300 '95 model US built that had a similar strong raw diesel smell when the boat was about 7 years old. I discovered that fuel filler hose from deck to tank was porous and outgassing. I replaced it with new hose (must have USCG approved) on the side marking. It solved the problem. It's relatively in expensive fix compared to a fuel tank. Good luck.

PS there was no noticeable fuel leaking and seem to remember calling Beneteau in SC and they made the suggestion to me. Their customer support has always been top notch for me.

 

[Boyd18185]

Thanks for that tip. I'm going to follow up. Although the odor is strongest around the tank itself, that clearly doesn't mean the source isn't somewhere else nearby.

 

[sailrj]

Check tank guage sender unit flange

We had an odor of diesel on our 351 after we were under way for a few minutes and it would not go away. When you got on board at the dock, initially the odor was not significant. The tank is under the aft birth and you could not sleep back there. No visible leaks. Finally checked the tank gauge sending unit flange and 3 of the 5 mounting screws were stripped and the gasket missing. Retapped the screw holes larger and used fuel grade silicone to replace the gasket. The odor went away and knock on wood, has not returned.