What sealant for diesel tank access lid?

geem

geem

Well-Known Member
Joined
27 Apr 2006
Messages
8,999
Location
European side of the pond
Visit site
I would like to inspect my diesel tank this weekend. It has a large manhole grp access lid secured by several m10 fittings. The tank is grp and built into the hull. When I take the lid off I assume there will be a gasket. I will likely need a diesel proof sealant to put the lid back as I noticed a slight weeping around the m10 threads. Any recommendations?
 
Adding a sealant to the gasket will probably help any weeping, but an access hatch to a tank needs to come off regularly and the sealant is a mess waiting to be cleaned up next time. Also, sealant makes the gasket slippery and likely to squeeze out when pressure is applied by bolts/screws. It might be better to put up with a weep or two?
 
I think Gold Hermatite?
But it was a long time ago, so I'd search the instructions etc on line.
What you do not want is bits of sealant getting inside the tank and blocking things.
 
Gaskets for diesel tanks need to be nitrile rubber, either as it comes, strips and sheet are available, or cork with nitrile binder, also available in sheet and perhaps strip form, not certain about that. There are suppliers on-line but cork is often available locally at motor factors. When done well there should be no need for an additional sealant but it is often not easy to get it perfect. Hylomar products are good but I have also used 'Instant Gasket' which seems to be silicone based.
 
Silicone RTV is ideal for this, dry the surface apply a thin smear and fix bolts finger tight.
After at least an hour (pref a day) tighten the bolts fully. you will need to tap the cover to release it next time.
I use it on all sealing jobs including engine gaskets, just don't get carried away and plaster it on.

I once used it as a temporary exhaust manifold gasket and it was fine but must be RTV. BMW specify it?
 
Just be careful you don't put too much sealant on and squeeze some into the tank. A previous owner had done this on my boat and it resulted in a blocked fuel line this summer, at a very inconvenient moment.
 
I used nitrile rubber sheet just check it is diesel resistant there is not a high pressure like some engine parts and it should be reusable .
 
parbuckle said:
I used nitrile rubber sheet just check it is diesel resistant there is not a high pressure like some engine parts and it should be reusable .
Click to expand...

Where do you get nitrile rubber sheet? My access lids are about 600mm diameter presumably so you can climb in to clean the tank (100gallon). I would need a large sheet to make a gasket from a single sheet without a joint.
 
geem said:
Where do you get nitrile rubber sheet? My access lids are about 600mm diameter presumably so you can climb in to clean the tank (100gallon). I would need a large sheet to make a gasket from a single sheet without a joint.
Click to expand...

Ahhh
 
You must log in or register to reply here.

Share this page

Top