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Ljwt330 · 03-07-2019, 08:59 AM

My 2004 Alpine 36FDDS has the fuel filler only on the driver side. The filler tube makes a close to 90* bend and heads to the tank, but the bend is very near the fill opening. The result, from my experience, is that I have to pump fuel very slowly or else the back up at the bend causes the "burp" and fuel spews out the fill opening. I can moderate that a bit by pushing the nozzle far into the tube and rotating the nozzle so the bend of the nozzle kind of matches the bend in the fill tube. That works fairly well, but I still have to fill slower than the lowest lock point on the nozzle handle and also watch/listen for fuel filling toward the opening. BTW, this is using the standard fill nozzle/pump, not the high volume truck nozzle.

So here's my question. Would it be possible to get a length of rubber fuel hose with an ID that matches the nozzle, push it on the end of the nozzle and run the hose into the fill tube just beyond the bend? That would give the incoming fuel a straight run into the tank. In theory, if the bend is causing the blow-back, this would eliminate the problem. The rubber tube would have a smaller OD than the fill tube so air could pass back out around it.

Do any of you with the same filling set up have an issue as I described and do you think my solution is possible/practical?

wolfe10 · 03-07-2019, 09:24 AM

Larry,

Before doing anything makeshift, crawl under and make sure the vent hose does not have a "drip loop"/sag in it.

That will also cause your symptoms and is easy to correct by routing the vent hose so it only goes down hill from filler to tank. May just require cutting an inch or two out of the hose or zip tying it along its route.

Bigd9 · 03-07-2019, 11:20 AM

Quote:

Originally Posted by wolfe10

Larry,

Before doing anything makeshift, crawl under and make sure the vent hose does not have a "drip loop"/sag in it.

That will also cause your symptoms and is easy to correct by routing the vent hose so it only goes down hill from filler to tank. May just require cutting an inch or two out of the hose or zip tying it along its route.

This was exactly how I corrected the "Burping" in my last diesel motorhome. It had a right angle filler also, and I messed and messed with trying to get it to fill the tank without burping. Then went I shortened the vent hose that fix the problem.

Ljwt330 · 03-07-2019, 11:40 AM

Quote:

Originally Posted by wolfe10

Larry,

Before doing anything makeshift, crawl under and make sure the vent hose does not have a "drip loop"/sag in it.

That will also cause your symptoms and is easy to correct by routing the vent hose so it only goes down hill from filler to tank. May just require cutting an inch or two out of the hose or zip tying it along its route.

Well, that was my first thought except there is no vent hose that can be seen. There is a clear view of the fuel tube all the way back to the bulkhead that protects the tank. No vent hose running parallel to fuel tube.

Bigd9 · 03-07-2019, 12:08 PM

On mine, the vent hose did not parallel the fill hose. The fill hose connected to the top left side of the tank, the vent connected to the tank top and took a different path to the filler. Does the filler pipe have a small vent hole inside near the inlet?

Here is a general filler pipe showing a vent

wolfe10 · 03-07-2019, 12:32 PM

Same for our 2003 38FDDS.

Ljwt330 · 03-07-2019, 12:51 PM

Quote:

Originally Posted by Bigd9

On mine, the vent hose did not parallel the fill hose. The fill hose connected to the top left side of the tank, the vent connected to the tank top and took a different path to the filler. Does the filler pipe have a small vent hole inside near the inlet?

Here is a general filler pipe showing a vent

No, no tap-in for a vent hose. Just a formed tube that bends toward the tank then is connected to a flexible/rubber tube. I'm heading to the MH now, just to confirm what I remember. I'll try to snap a picture as no one seems to have this issue. Don't know if a major change in this area was made between 2003 and 2004 MY.

My real suspicion is not a build up of air in the tank, but an obstruction, the bend, in the fill tube. However, nobody else seems to have that bend.

Tom and Patty · 03-08-2019, 06:40 AM

Have you ever tried filling at the truck islands?
We do have a vent tube that I re-routed but that didn’t fix my problem of filling at the rv island.....with the nozzle constantly shutting off because of burping.
For years now I have used the truck islands and it fills wide open.
Back at the rv island......takes forever to fill.
Can’t explain it.

Bigd9 · 03-08-2019, 06:59 AM

Quote:

Originally Posted by Tom and Patty

Have you ever tried filling at the truck islands?
We do have a vent tube that I re-routed but that didn’t fix my problem of filling at the rv island.....with the nozzle constantly shutting off because of burping.
For years now I have used the truck islands and it fills wide open.
Back at the rv island......takes forever to fill.
Can’t explain it.

That is weird. Normally it is the other way around!

You know, in the last 20 years with a diesel motorhome, I can count on one hand the number of times I fueled at a truck island. I just prefer the smaller, slower paced fueling stations.

Ljwt330 · 03-08-2019, 08:28 AM

Quote:

Originally Posted by Tom and Patty

Have you ever tried filling at the truck islands?
We do have a vent tube that I re-routed but that didn’t fix my problem of filling at the rv island.....with the nozzle constantly shutting off because of burping.
For years now I have used the truck islands and it fills wide open.
Back at the rv island......takes forever to fill.
Can’t explain it.

Agree, that's strange. I've never even entered a truck island because of the issue with the slower fill nozzles.

The only consistency I've noticed in these responses is that similar coaches to mine that do not have the problem are all earlier models.

Yesterday, I forgot to double-check the fill tube route to find the vent tube, if there is one. However, being well aware of the back-flow problem, when I had issues filling, I took a careful look for the vent tube and didn't see it.

One more specific question to anyone with any year Alpine with front door. Does your fill tube neck, driver's side only, have a severe bend located a short distance from the opening?

Tom and Patty · 03-08-2019, 08:56 PM

Quote:

Originally Posted by Bigd9

That is weird. Normally it is the other way around!

You know, in the last 20 years with a diesel motorhome, I can count on one hand the number of times I fueled at a truck island. I just prefer the smaller, slower paced fueling stations.

If I fill at the RV island it is really a slow pace. We will be there 20 minutes.🤔

AKOne · 03-10-2019, 06:47 PM

Quote:

Originally Posted by Ljwt330

Does your fill tube neck, driver's side only, have a severe bend located a short distance from the opening?

Yes, same as yours. The burping blowback, whatever it is called, is why I dislike fuel stops. Whenever possible, I try to fine a fuel islands where the coach will sit on a frontend high incline. The steeper the better. I can put in a full tank in much less time. However, slanted to the driver side or downhill at all, becomes an exercise in futility.

Ljwt330 · 03-10-2019, 08:14 PM

Quote:

Originally Posted by AKOne

Yes, same as yours. The burping blowback, whatever it is called, is why I dislike fuel stops. Whenever possible, I try to fine a fuel islands where the coach will sit on a frontend high incline. The steeper the better. I can put in a full tank in much less time. However, slanted to the driver side or downhill at all, becomes an exercise in futility.

Thanks for the response, it describes exactly what I do as well.

Ljwt330 · 03-11-2019, 04:46 PM

Well, got back the the MH today and looked closely at the fill tube behind the bulkhead. Indeed, there is a vent hose, something I did not notice before.

The hose is zip-tied alongside the fill tube and follows the path of the fill tube, but as it bends toward the fitting in the fill neck, the vent hose actually wrapped under the fill tube, came around the other side to the top, and connected to the nipple on the neck. I disconnected the vent hose from the nipple and brought the hose along the top of the fill tube removing the wrap underneath. Knowing the issues with low points in the vent tube, this seemed to be the problem

Now, I say the problem is "maybe" fixed because the station I went to for a fill-up had the slowest pump nozzles on record! Even at the highest setting, the fuel flow was painfully slow. End result, I filled the tank with no "burping" issues and no blow back. I'm hoping the vent tube was the fix but I won't be sure until I refuel at a station with a faster flow.