LanceK

I am interested in the fuel vent mod, but something tells me it was designed that way for a reason.

Are there any potential safety issues with this setup?

TIA

njmaier

My understanding is that the extra tank space is for fuel expansion. I've installed the kit, and I have never had any fuel spill out of my tank...even on the hottest days around here (around 95-97 degrees).

If I'm wrong someone please correct me.

TonyB

DC uses the same tank (at the factory & replacement) for gasoline and diesel. Gasoline has a high vapor pressure & needs room to expand. Diesel fuel does not need that much room for expansion.

I have the vent installed for 1 month now & we are hitting 100-110f days. I have not had an issue....that's the practical answer.

From a design perspective, I'll have to look up the different coeeficients of expansion when I get home....Now you've got me thinking!

Tony

8mpg

Im with Tony... 100* weather and near 40 gal in the tank with no issues

4x4not

Like what TonyB said.... they use the same tank. The government requires a certain % of the tank capacity in air space for safety reasons. They had good reason with gasoline, but with diesel it is unnecessary. I haven't had one single issue with mine in the 7 months the kit has been installed. I fill aaaaaall the way up to the top of the neck, and then drive ~7 miles home. It is 90° today, and no issues.

One thing you should also do when dropping the tank is fix the "open air vent" issue. Do a search and you'll know what I mean.

LanceK

My concerns revolve more around the tank getting punctured in an accident and increasing the odds of explosion etc.

I have no idea is this is a concern or not which is why I asked the question.

If the mod has no safety issues I will probably add it to my list.

RustyJC

I haven't seen the mod, but is the vent line relocated above the rollover shutoff valve in the fuel filler? If so, this would be a safety issue.

Rusty

iweb

Does the extra fuel in the tank change the OH computer so its way off on MPG and such?

NB64

I've had this mod for over a year no problems at all. I have a towing range of 450 miles and a commute range of around 600 miles. Never taken a long non towing trip yet. Does not effect the over head. Although it won't show a 600 mile range on the over head it will reach the 500 area and stay there for a long while. I get about 149 miles before the needle moves from the full pin. Well worth the $35.00

Jmac

I've had the mod for about a year and a half. I get about 155miles before the needle comes off the full peg. I haven't had any issues with it at all.

Jamie

blord

The coefficient of volumetric expansion for gasoline is .00069/ deg F. Diesel is .00049 / deg F.

So, assuming the temperature of the fuel coming out of the ground is roughly 60 degrees and it will rise to 100 degrees and you fill a 35 gal tank:

Diesel will expand by .644 gallons
Gas will expand by .97 gallons

Since tank capacity will expand the same for either fuel it can be ignored.

So I would say that unless you have it right at the brim and don't drive it after filling you won't have any overflow problems. If you drive it 12 miles (figuring 20/gal) then there definitely shouldn't be a problem.

Jmac

Slept at the Best Western last night didn't you!!!

blord

No, if I had I wouldn't have had to look up the expansion numbers!

C Schomer

This is the first I've read about this mod - it sounds slick! The thought of $100+ fillups is a little scary! Craig

trik396

Had mine installed for about 6 months now. No problems either. I get about 36-37 gallons to fill. I was worried that those "vents" at the top of the tank might leak alittle. Nothing so far and I haven't modded the vents with a filter or anything yet.