Somebody correct me on this if i misunderstood, but is the harpoon mod just to enable a quicker fill-up? I'm sure I am missing some other benefit...

 

Quicker and a little more fuel as well.

 

All of the harpooners I have read about have been very happy that they did so.

 

Did it onmy 01 but not on the 05 yet. Too paronoid with the warranty issues .

 

I have driven over 160 miles on a trip before the needle fell below the full mark.

 

But once it hits full, stand by and watch reality set in.
It is nice to have the added capacity. And it takes sooooo long to top off without the harpoon. Some day, oh some day, I'll break down and do the harpoon thing.

 

OK, so no drawbacks. What is the purpose of the way the tank was designed? Is there potential for venting fuel overboard under certain circumstances (hot day)?

 

Attendant?!?!?!? Out in California, You'll pay like $3.40 a gallon for fuel if you use an attendant ! Is that a normal thing in Jersey?

Oh ya...I fill mine as far as I can before a long towing trip.

 

I don't think you can pump your own fuel in NJ!!

 

I suppose, if you fill a harpoon tank to the top on a cool summer morning, then park her in the sun. But at 17MPG +/-, if you fill and roll, you'll be down far enough before you stop not to spill over. The reason for the harpoon is to more quickly get all the fuel into the tank that it wll reasonably hold. The vent tube sticks down into the tank so far that a 38 will barely hold 35. And that is with a 15 minute fill!

 

Yep, one of the few good things left in this state--cheap fuel and somebody to pump it!! It is actually illegal to pump your own GAS, but that is what the law states..."GASOLINE" only...so you CAN pump your own DIESEL!

 

Its the same tank that the gassers use so thats why they have the extra space for the gas to expand on hot days . Diesel doesn't expand like gasoilne does so we take as much space as we can so we don't have to stop as often.

 

The gasoline vehicles need the air space at the top of the tank for the fuel vapor recovery system to function correctly; all part of emissions requirements.

As far as filling the diesel tank...
As you put fuel in the tank the fuel will displace air; the air will go out the vent tube (that sticks down a few inches from the top of the tank) which has a vent hose back toward the top of the filler neck. Once the fuel level has risen enough to cover the vent tube there is no easy way for the air to be displaced; fuel backs up the filler neck and hopefully the pump cuts off. You can then slowly fill the tank to the brim as the air being displaced goes back up the filler tube.

Cutting off the vent tube (harpoon mod) allows more fuel in the tank because the air can freely escape via the vent tube to a higher fuel level.

My only regret is that I did not do this mod earlier.

Bob

 

I second this statement. Before the mod, it took at least 15 minutes to fill. 5 for the pump to click and 10 to complete. Now, it's about 6.

As for the leaks, when I first harpooned, I didn't get the sending unit ring on straight, and I had some drips. I re-did the ring and haven't lost a drop since.

 

There is not separate tanks for gas vs diesel engine trucks and the EAP requires, I believe, a 10% expansion area for gassers after filling up. So a 28 gallon tank would be expected to hold about 31 gallons at a minimum. If you want to have some sticked shock fill a 44 gallon X to the neck!!!

RoyC