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Replacement of the fuel filler necks with an improved design

February 2009

We, like apparently many others with a 2004+ Horizon/Vectra, have had problems fueling - if the pump nozzle (truck or auto) is placed on its lowest flow rate, the handle will click off with about 20 gallons left to fill on our 100 gallon tank. Getting that last 20 gallons in the tank can take a long time; I discovered of the last 20 gallons, the first 10 gallons or so must have a flow rate of not more than about 0.1 gallons per second, or if my math is correct, six gallons a minute. The last 10 gallons can take an eternity and must be trickled in. If I had a 150 gallon tank, no big deal - I would consider it a 130 or 140 gallon tank. Since the tank is only 100 gallons, every gallon counts.

Every fuel stop was an adventure in patience, for us as well as those behind us. It was one of those minor but completely aggravating and annoying issues we get to deal with in life from time to time. It was also a reminder that our coach, while a really good well thought-out and built product, was not without its warts.

It was with great glee I noticed a thread several months ago on a popular RV forum about Freightliner and Winnebago addressing this problem. The problem was apparently inadequate venting - about 400 fuel tanks were going to be replaced, and on other chassis numbers, improved filler necks were the solution (this latter category includes us.) If your unit was in warranty, no charge for parts and labor. Out of warranty, the owner pays for parts, Freightliner covers the labor.

This was apparently one of those "soft" recalls - it is available only if a customer complains and is not proactively offered by either Freightliner Custom Chassis or Winnebago Industries.

The improved filler necks have a vent pipe of 7/8" compared of a vent pipe of 1/2" on the old version. The new tank has a 7/8" vent on the top of the tank, the old tank has a 1/2" vent near the top, but on the side. I have no idea what the problem is with the 400 or so tanks that are being replaced. As previously mentioned, my tank was not a candidate to be replaced, but installing filler necks with a 7/8" vent tube to a tank with a 1/2" vent outlet doesn't make a whole lot of engineering sense to me. My guess is this was a cost-driven decision and not an engineering decision.

Freightliner of Tolleson, Arizona (Phoenix) is about the only Freightliner dealer I will let touch my chassis (besides the factory), so I made an appointment with Kirk, the Oasis manager, to have our new filler necks installed. Kirk (and the tech) said they have replaced two fuel tanks in the campaign, but no filler necks - lucky me.

The installation of the left side went fairly well with no complications (other than the tech bolting some parts together that needed to move when the slide was extended - guess how we discovered that!), but the right side filler neck took a wrong twist and some of the pipe had to be cut off to make the installation work. I can't believe that field modification was necessary, but I saw the issue with my own eyes. There must be about ten man-hours of labor in this job - I sincerely hope the results are worth the cost.

After the tech was finished, he wanted us to try a fill-up, so we drive the mile or so to a nearby Pilot. It was extremely busy at the station and for the first time ever in 40,000 miles of using mostly truck pumps, we had to pre-pay for a specific amount with our Visa card. I thought we needed 48 gallons according to our VMSpc engine/trip computer, so Jane pre-paid for 48 gallons of fuel. (I don't know if pre-paying is a local policy, or a corporate policy, but Pilot is now on the very bottom of our fueling list.)

With the truck pump nozzle set on its lowest position (lowest flow rate), it clicked off at 33 gallons of fuel pumped, leaving us short about 15+ gallons.  Those 15 gallons did seem to go in faster with the new filler necks, but we won't have a good feel for this until we have two or three more fueling experiences. I'll going to leave a little white space under this paragraph so I can add later comments.

May 2010 update

As much as we wanted it to work, the new filler necks unfortunately did not solve the slow fill problem. We lived with basically the same problem for a few months, then I got the idea to call Freightliner since I know Freightliner has replaced fuel tanks in the past for owners with similar issues. They readily agreed to install a new tank and the fellow remarked the new filler necks did not solve the problem (ain't it the truth!)

We made an appointment to have our new tank installed at the Freightliner factory service center in Gaffney, SC summer of 2009. It is about an all day job. When our coach was brought out after the job was completed, I managed to talk to the tech. He said they replace at least one tank a month for the same problem. Another employee remarked they told engineering the new filler necks wouldn't solve the problem, but Freightliner was obviously trying to solve the problem on the cheap.

The basic problem was the tank vents exited on the side of the tank near the top, the new tanks have a larger diameter vent out the top.

With our new tank and filler necks, we can now fill at any high flow rate truck pump on the highest setting and almost completely fill the tank in about five minutes or less. I think we are two to five gallons shy of being completely full!!

Even though my filler neck replacement article has little value today, here are the pictures anyway. Maybe you will find it a little interesting.

Old vs new filler necks

Sorry about the horrible picture quality - it's from my Motorola RAZR2 cell phone. The large pipe with the hose barb in one of the new fuel necks fill tubes, tank end. Of course you can see the differences between the two vents

New necks as unpacked

The new filler necks as unpacked

New filler necks

Tank end of the new necks

Tank end of the new necks

Tank end of the new necks

Old neck mounting plate as cut out

The cut-out old filler neck mounting plate. This is where the fill neck sticks out (where you place the pump nozzle.) The tech drilled out the spot welds on the second one which was much quicker than hacking this one out

New neck plate

New filler neck mounting plate (another bad cell phone picture)


This is what happened when we tried to extend our slide when Freightliner was all finished! The tech bolted (with hub bolts that can't be removed except by grinding) the filler neck plate to some sheet metal that moves out with the slide. So we got two more nights of free camping at Freightliner (this happened on Friday afternoon at quitting time.) Julio the tech had us reasonably well repaired Monday morning and we were finally on our way - yea! Later, I did a much better repair job