Fuel Tank Vent Kit - New ?'s

[ERohloff]

Lot's of recent threads re Vent Kit and seems a good thing to do. Just picked up my ordered 3500 last week - Great truck so far, Even better than I expected! Did the 165 point "New Truck Inpection List" found on this forum and Not One issue!!!



David's vent kit is "In the mail" so hope to install it as soon as can run the tank down low. Questions:

1. Is there and danger of running the tank too low? Say to 50-60 miles past DTE. That should still leave a couple of inches of fuel in the tank. Does running the tank that low harm the lift pump (The '05's as most of you know have the LP in the tank)?



2. Think I saw somewhere that adding more fuel to the tank(say 38-40 gals) causes the OH mpg value to be "off"... ... Not sure why that would be the case. Any validity to this or was I just dream'in?



3. David's e-mail Vent Kit instructions state that " This Vent Kit modification will likely void the gas tank warranty". Likey true, but any chance that doing this and the venting the two tank top nipples thru a fuel filter(to keep intake air clean) Another Good Idea ... would void the lift pump inside the fuel tank?



Voiding a tank - Not such a big deal. Voiding a lift pump - Another story!

Comments - Too paranoid???

bob r...

 

[Hokey]

I mailed an order today also for the vent kit and have an 05 but, I quit worrying about "warranty a few bombs ago" I wouldn't think it would /should Void the warranty on the fuel pump. But stranger things have happened. just my opinion--I'm going for it cool idea.

 

[Pawpaw]

1. Is there and danger of running the tank too low? Say to 50-60 miles past DTE. That should still leave a couple of inches of fuel in the tank. Does running the tank that low harm the lift pump (The '05's as most of you know have the LP in the tank)?

With a new truck, you might not make it 50-60 miles past DTE. On my truck with 40,000 miles, I went about 20 after and I guesstimate I had about 3 or 4 gallons left.

2. Think I saw somewhere that adding more fuel to the tank(say 38-40 gals) causes the OH mpg value to be "off"... ... Not sure why that would be the case. Any validity to this or was I just dream'in?

I can't see how it would, either. My OH display (and I think most others) has always read between 1 and 3 MPG low. I'm still running on my first tank after the vent kit install, so I don't know for sure.

3. David's e-mail Vent Kit instructions state that " This Vent Kit modification will likely void the gas tank warranty". Likey true, but any chance that doing this and the venting the two tank top nipples thru a fuel filter(to keep intake air clean) Another Good Idea ... would void the lift pump inside the fuel tank?

I can't see how it would, but you know how some dealers are. All you will have really done is relocate the tank's main vent. As for the two nipples, they're still free to breathe or whatever it is they do. Completely capping the nipples MIGHT allow the lift pump to pull a vacuum in the tank, but venting through a fuel filter can do nothing but good. At worst, it will do nothing.





Bob

 

[TCDiesel]

When you run the tank down the fuel will get warm, not so bad up here in MN but down south could run higher pump temps. the Dmax has a fuel cooler stock. Their CC/EC/SB has only a 25 gallon tank.

 

[Gypsyman]

The OH mpg won't be off but the DTE will stay the same until the extra fuel is burned and the float starts to move. I had one of the original kits and just changed the routing last weekend. I added hose to the open vent lines, made the additional vent added by the kit into the only vent, and used the factory (lower) vent for the fuel return on my RASP. Works perfectly.



Unless you have to make a tank warrenty claim most techs will never notice the additional line even if they're looking.



Richard

 

[Spooled-up]

BRohloff

I'd probably go only about 20 miles or so beyond 0 on the overhead. You'll only have about 3 inches or so in the tank. I was able to get under the tank and lower it down onto my body and slide out from underneath it. I'd guess it weighs somewhere around 40lbs or so. It was a dirty job, but it was the third time I'd done it, so I didn't want to take the time to slowly lower the tank down a 4x4 block at a time.



Keep in mind that this kit's main purpose is to save you time. Nothing is different if you already take the considerable time to fill your tank to the very top. You won't have to slowly trickle the fuel into the fill neck and let it settle down and repeat until you see fuel in the neck. If the overhead works fine when you fuel with the stock vent, it will be the same with the new vent.



As for voiding the warranty, it may be voided on the tank or it may not. I've actually had 2 different dealers install the kit for customers, and one said he would buy a few from me. He never did, probably because it's not a Chrysler approved modification. I don't think most dealers would honor a warranty claim on your tank after this modification though. on my tank, both of the small hose barbs on top of the tank are closed off as far as I can tell. If they are not, I would think that there would be leakage when fueling as some have reported.

 

[Spooled-up]

By the way, I've made a small modification to the kit again. It's no longer necessary to buy the thread sealer. I've found a fitting that allows you to install the bulkhead fitting with the 90 degree elbow already attached. It isn't necessary to disassemble the fittings to seal them up because I seal the threads for you now. Sometimes the thread sealer was a little tricky to find.

 

[ERohloff]

I like the idea of venting all three issues (The air locked hump, and the two nipple fittings) into one vent to the original vent line. Will look at it when the tank is out.

Thanks for all your input. Sure helps to have a little info ahead of the game... ... .

bob r...