2nd Gen Non-Engine/Transmission Fuel Cap Vented or not?

[bry1216]

Simple question is the original fuel cap vented?

 

[B.G. Smith]

No. bg

 

[HHhuntitall]

?!? I thought they were? They allow a slight amount of vacuum accumulation before allowing it to vent into the tank, so if you pull more fuel than the small tank valve can let in air, it will vent... . It won't vent out, though. It holds pressure in the tank, IIRC.

 

[cerberusiam]

HH, I think the tank vents negate any need for a vented cap. They should be open all the time unless in a roll over condition. There is no vapor recovery system on a diesel which is the only reason to have a vented cap.

 

[B.G. Smith]

IIRC there were some tanks collapsed because of a red cap on the tank vent from the factory. bg

 

[Regcabguy]

IIRC there were some tanks collapsed because of a red cap on the tank vent from the factory. bg

Mine was one of them. Dealer did not remove the red vent cover from the factory resulting in a collapsed tank and premature demise of the lift pump. Got both replaced under warranty. This was on my '98. 5. Prior to this,everytime I loosened the cap I got a vacuum coming off the tank.

 

[bry1216]

I was able to find the answer. Cap is not vented because of the rollover valve on top of the tank - I always fill my tank until I can see diesel and never have a leak, so the floating valve must be stuck and I got a vacuum problem. I will be drilling a 1/16 inch hole in my cap.

 

[VolsFan]

The rollover valve on my 99 got clogged up with junk and I could hear a hissing noise coming from the cap, sounded like the tank was collapsing. Got in there and cleaned the valve out and solved it. I tried the vented cap and it didnt really change anything for me.

 

[bry1216]

Thank you VolsFan!!!
I understand what you are explaining... . There is a spring loaded plate on the inside of the cap for over pressure. Drilled a hole in it, also!

 

[bry1216]

The rollover valve on my 99 got clogged up with junk and I could hear a hissing noise coming from the cap, sounded like the tank was collapsing. Got in there and cleaned the valve out and solved it. I tried the vented cap and it didnt really change anything for me.

I hate to mention this but after drilling the holes you have to test the cap ... ... ... ... . To keep it PG rated, I will leave this up to your discretion.