venting gas tank on ex-diesels
 

1986 k30 diesel now has a 400 in it tank does not vent.

I remember after I built this truck drove it to the gas station and the gas tank had a large vacuum. Hissed like crazy after cracking the cap. So my way of fixing it was drill a small hole in the gas cap. Problem with that is can't ever fill it over 3/4 tank or it splashes out. So 10 years later I think it's time to fix it right

So anyone run across this before? Is there a vent on the diesel trucks that is maybe clogged or do I need to change sending units? Probably need to change filler necks also as this 3 inch hole that comes with the cucv trucks sucks for filling up

Re: venting gas tank on ex-diesels
 

On my truck I got rid of the charcoal canister. On the vent line on the sending unit I added a small rubber hose with a differential vent on the end. I also used a vented gas cap.

Re: venting gas tank on ex-diesels
 

You might have to switch over to a 3 line sending unit if your former diesel didn't come with one.

Re: venting gas tank on ex-diesels
 

I don't think it does , only seen the feed line and the return line coming of the tank.

Re: venting gas tank on ex-diesels
 

Other way around. Diesels use vented caps, Gas systems vent into the charcoal cannister to store the fuel. When the caps are left at the gas station (easy to do on a dual tank system) un-knowledgable persons replace the hard-to-come-by vented cap with the easy-to-get sealed gas cap. If you don't put the proper emissions system in, including 3 line sender and and cannister, you will need a vented gas cap.

It took me some time on the internet to find the correct diesel cap. My problem was the tank built pressure, then when I had to replace a line it sprayed me down with diesel.

Re: venting gas tank on ex-diesels
 

That would probably be the easiest fix but I need to change my filler neck to a normal one
Really don't want to drop the tank

Guessing something like this will work.

part Number - 10819D Green Diesel Fuel Only cap helps prevent accidental fuel contamination Made of sturdy, long-life materials 2-13 16 in. Prevent Pressure vacuum 1-49 64 in. x 2-9 64 in.

https://www.amazon.com/Stant-10819D-...s=stant+10819d