Diesel fueling problem... what's the right fix?
November 16, 2014 1:56 PM   Subscribe

I have a Golf TDI that I've been fueling just fine for three years. Today, I could not fill it up; diesel kept splashing back as soon as I'd start fueling and the pump would stop. I got about three gallons in by pumping extremely slowly, but that's it. I tried at a pump with the large-size truck nozzle and one with a normal car nozzle. I have an appointment to have it looked at, but I'm not sure what the ideal fix is...

I do not have the new misfueling guard on my car, which prevents people from putting a gas nozzle in a diesel car. The VW dealership told me that not all gas stations have nozzles that work properly with it, so it would be better to not get the guard.

The regular guard that came on the car seems like it's broken-ish, like partly pushed in maybe, but it's looked like that for ages. Is that the likely problem or is that how it's supposed to look?

Can you help me with what I should expect from a fix? Does it sound like the existing guard is broken? Would the misfueling guard help me, or just cause trouble at certain pumps? I'm nervous about getting stuck somewhere unable to fill up the car. Is there a trick to getting fuel in there even if the guard or nozzle is problematic?
posted by dayintoday to Travel & Transportation (9 answers total)
It is probably nothing to do with the guard. Likely you have an overpressure condition in the tank caused by some kind of malfunction in the emission control-if you are someplace cold a valve could have frozen closed/open. Can you park the car someplace warm for a couple of hours? You could also leave the gas cap off (with the car stopped and not running) for while to see if that relieves the pressure.

If that isn't it (and I am not an expert on diesels), I don't know.
posted by bartonlong at 3:00 PM on November 16, 2014

With the cap open, the tank is open to atmosphere, so there is not some residual pressure issue there. Presumably something has come adrift in the neck and so it is restricting flow, which in turn causes the flow to back up while filling and trigger the pump to stop. My suspicion is that the plastic moulded hose that goes between the filler and the tank itself is somehow blocked or constricted.

I don't think there is much you can do beyond get them to look at it, but I suspect it's something minor, but with big consequences. Possibly even not a massively expensive fix.
posted by Brockles at 3:19 PM on November 16, 2014

Was there a sudden, sharp decrease in ambient temperature where you live between the time you last filled your tank and today?

If so, I would guess whatever mechanism equalizes pressure in your tank has failed at some point, and the drop in pressure in the tank caused by lower vapor pressure of the diesel fuel at lower temperatures has caused the filling neck of the tank to collapse in on itself.
posted by jamjam at 3:32 PM on November 16, 2014

Response by poster: Thanks, all! It's chilly here (around 40 day, 20s at night), but not a huge drop since last I filled up and far warmer than the coldest it gets around here.
posted by dayintoday at 3:52 PM on November 16, 2014

Don't get the misfueling guard! My dealer put it in against my will and it is loathsome. Pumps that happen to have the "right" nozzles are fine, but pretty much everywhere else you'll trip the sensor 3-5 times per gallon, and then you'll end up a) forming a detailed map of which pumps are happy and sad in your area, and b) looking like an idiot wasting your time waiting around for the happy pump while the sad pump sits vacant. Or else filling your tank most-of-the-way by dead reckoning and having to stand there the whole time. Grrr.
posted by janell at 8:28 PM on November 16, 2014

Could it also just be a shitty gas pump? I've had this exact problem on my Jeep at certain gas stations but not others.
posted by Thistledown at 7:12 AM on November 17, 2014

Response by poster: It's not the pump. I used two different pumps at the same station (the station I go to 99% of the time) and a pump at another nearby station.

I appreciate the above responses, which will help me sound more informed when I get to the dealership!
posted by dayintoday at 7:28 AM on November 17, 2014

Response by poster: As a followup for anyone curious... it wasn't the guard, neck, pressure, or any of the above, according to VW. They can't figure it out, so they're just replacing the entire fuel tank. Seems extreme, but it's covered under the emissions warranty.
posted by dayintoday at 12:59 PM on November 18, 2014

I have this same issue (on my 2012 TDI Golf) only when I refuel with about 1-3 gallons in the tank. Less than that or more than that I have no problems.
posted by n9 at 10:36 AM on July 29, 2015

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