fuel tank questions
I don't know where you folks get all this. Here is the deal:
ALL Mopars of the cars of which we speak used UNvented caps. The vent in the tube worked GREAT and has almost NO problems. Only troubles you might find with this is:
1....If "some bugs" (mud daubers, etc) made a mud plug in the tube with car parked long term, etc
2....If the tube rusts through or somehow gets damaged. Damage is rare, as it is fairly well protected
3....A VERY rare case might be you are in San Fran on the steepest hill you can imagine, parrallel parked with the cap down hill and the tank REALLY FULL on a HOT DAY. How rare is THAT!!!??? The vent might leak some fuel, which would drain "pretty much harmlessly" into and then out of the rear frame rail.
You want the factory VENT TUBE and you want a SEALED cap
Here is a screenshot of how this is laid out. This is right out of the factory manual The bottom of the tube ends INSIDE the rear frame rail
This system was used up through 70 IN CALIFORNIA when CA started using the "new" carbon can/ evaporative emissions controlled. From 70--forward, several changes were made. For a couple of years, a vapor separator can was used in the trunk. Then, the separator was made inside the tank. In the following years there were SEVERAL changes in fuel caps known as "pressure / vacuum" caps. THESE CAPS ARE NOT VENTED in an operational sense. They contain a pressure and a vacuum pressure relief. So as vacuum or pressure builds, they will relieve.
THE OPERATIONAL VENT IN ALL OF THE EVAP CONTROLLED TANKS regardless of year was provided by the tube going all the way to the engine bay, for the evap/ carbon can system.
I don't know where you folks get all this. Here is the deal:
ALL Mopars of the cars of which we speak used UNvented caps. The vent in the tube worked GREAT and has almost NO problems. Only troubles you might find with this is:
1....If "some bugs" (mud daubers, etc) made a mud plug in the tube with car parked long term, etc
2....If the tube rusts through or somehow gets damaged. Damage is rare, as it is fairly well protected
3....A VERY rare case might be you are in San Fran on the steepest hill you can imagine, parrallel parked with the cap down hill and the tank REALLY FULL on a HOT DAY. How rare is THAT!!!??? The vent might leak some fuel, which would drain "pretty much harmlessly" into and then out of the rear frame rail.
You want the factory VENT TUBE and you want a SEALED cap
Here is a screenshot of how this is laid out. This is right out of the factory manual The bottom of the tube ends INSIDE the rear frame rail
This system was used up through 70 IN CALIFORNIA when CA started using the "new" carbon can/ evaporative emissions controlled. From 70--forward, several changes were made. For a couple of years, a vapor separator can was used in the trunk. Then, the separator was made inside the tank. In the following years there were SEVERAL changes in fuel caps known as "pressure / vacuum" caps. THESE CAPS ARE NOT VENTED in an operational sense. They contain a pressure and a vacuum pressure relief. So as vacuum or pressure builds, they will relieve.
THE OPERATIONAL VENT IN ALL OF THE EVAP CONTROLLED TANKS regardless of year was provided by the tube going all the way to the engine bay, for the evap/ carbon can system.
