Neoprene

[guydickinson]

I thought this it might be useful to others who have neoprene gaskets under the lid of their diesel tanks. I did (and it was originally recommended) - but my engine stopped not long ago. Thanks to a very astute local marine engineer the cause was rapidly discovered. Bits of neoprene floating all over the tank and a horrible sticky black sludge. The reason I’m told goes something like this. There is now a lot of biodiesel (20%?) in diesel. This apparently attracts water so alcohol of some sort was added. This attacks neoprene and turns it into small bits which block pipes. I’m now trying to clean the tank. Cork gasket next time. Hope that information might prove useful although I may’ve been the only one in ignorance!!

 

[VicS]

I thought "nitrile" was the recommended gasket material for use with diesel rather than neoprene?
Don't know if ok for bio- diesel though

 

[guydickinson]

Might’ve been nitrile. But cork is apparently the thing now.

 

[vyv_cox]

Might’ve been nitrile. But cork is apparently the thing now.

Cork gaskets are made from small particles bound with an elastomer, nitrile for hydrocarbons, EPDM for water. For better resistance to fuel you might need Viton but I don't know if this exists with cork.

 

[vyv_cox]

Cork gaskets are made from small particles bound with an elastomer, nitrile for hydrocarbons, EPDM for water. For better resistance to fuel you might need Viton but I don't know if this exists with cork.

This link explains Composition Cork & Cork Rubber Gaskets & Materials | Excelsior

 

[jwilson]

I had a black rubber gasket supplied with a diesel tank fitting that quite rapidly went very soft and sticky (and leaked). Made a new one out of cork/nitrile and it's been OK for years now.

 

[Zing]

Nitrile ought to be ok. It’s used in fuel hoses.

 

[thinwater]

Nitrile. Neoprene was a mistake in this application. Not cork.

(a career in refining)

 

[vyv_cox]

Nitrile. Neoprene was a mistake in this application. Not cork.

(a career in refining)

That may be true of heavy walled vessels in refineries but the compressibility of nitrile bound cork is invaluable in sheet metal fuel tanks. Very common in automotive and marine applications .

 

[guydickinson]

I thought it might be useful to warn people. But there we are! I imagined boats with engine failure all over the place!

 

[thinwater]

That may be true of heavy walled vessels in refineries but the compressibility of nitrile bound cork is invaluable in sheet metal fuel tanks. Very common in automotive and marine applications .

True enough. Cork/nitrile. There is also cork/neoprene marketed for fuel gaskets--avoid it.