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The problem I am still having is that sometimes I have trouble fueling up. Most of the time I am able to refuel without any problems, the pump does not click off before the tank is full. But then more often than not the pump will click off before the tank is finished. for instance, the other day it shut off when the fuel level was at 90%, so I went to another gas station to refuel. At that gas station it also refused to put any more fuel in, even though the tank was at 90%. I drove for a couple days, tank went down to 80% and was able to refuel to 100% at a different gas station, no problems, the pump did not click off and prevent me from fueling further.
I've been testing it for a long time, and at many different pumps and sometimes it will just click off four or five times in a row, and then fill all the way to 100%. IT's very strange. Any ideas what could cause this ? maybe some kind of electronic like a vent valve being stuck in a weird position? or perhaps a very tiny clog somewhere? It still doesn't make sense that it will have trouble SOMETIMES and then at other times, no problems at all.
And yeah I can smell fuel drifting off the rear of the vehicle near the fuel tank when it's running. But once the engine is shut off, the smell goes away quick. No visible leaks or anything visible and the charcoal canister checks out. No codes whatsoever. I'd like to reiterate, I only have the difficult fill situation SOMETIMES, but it happens kind of a lot at random.
Last edited by neatchevy; Dec 26, 2025 at 3:10 AM.
also there is oil seeping down from the fuel tank creating an oil spot on the tank. is it even possible for oil to get in that area? it's just a 4 inch by 4 inch spot dripping down from where the fuel pump is situated above.
Last edited by neatchevy; Dec 27, 2025 at 10:46 PM.
also there is oil seeping down from the fuel tank creating an oil spot on the tank. is it even possible for oil to get in that area? it's just a 4 inch by 4 inch spot dripping down from where the fuel pump is situated above.
Are you sure it's not fuel?
I think the rear brake lines run over the tank and if you have rear AC the refrigerant and coolant lines run over or near the tank. Brake fluid or AC refrigerant would be oily for sure.
Yeah I am sure it's not fuel. Doesn't smell or look like fuel. I think just one brake lines crosses over the fuel tank, but only does so further down FROM the source of the leak. It's a cargo van, so It doesn't have rear heat, unless there's something crazy I don't know about.
OK I figured out where the Fuel smell is coming from ! FINALLY! I used the borrowed creeper I have (aka THE LAND YACHT) and getting the worlds best AB workout I was able to stick my neck, honestly get one eye ball up there on the fuel pump. There are two places where I was able to squeeze my small head in between the exhaust and diff on the chevy express. One is further towards the rear wheels in between the at the end of the cat and in between the diff. I stuck my head up there and could see the fuel pump assy. I was hanging onto the diff like a monkey with my hands to relieve some of the pressure on my neck. I stuck my hand all over the pump feeling from leaks on that side and NADA. SO I went to the OTHERSIDE of the fuel tank where the filler neck is. I was able just to get one eye ball on the fuel pump from that side and ... I noticed wetness on the plastic part. This is the plastic part guys... Derrick... Triage...
It;s that round peice in between the connectors that is wet. I stuck my finger in there just barley and pulled it out. I smelled and it smelled like fuel. So that's the leak. Now it all makes sense because I was able to smell fuel on the same level as the fuel pump. Meaning the fumes kind of float around on top of the tank because fuel fumes are heavier than air. They kind of stay up there but when I smell fumes It's on the same plain as the fuel pump because the fumes hang out there.
so I guess what I want to know to is how the heck does that little plastic piece get broken? I can tell the van has taken an impact on the frame near the pump, but the fuel tank itself has no damage to it. I also know that the van sat for a quite a long time... could this just be corrosion as the fuel tank is suppose to be emptied in order to store it long term? or perhaps the fuel tank was siphoned because i am pretty damn sure the cats were stolen off it when it was sitting at the used dealership, so it would only make sense the thieves could've possibly damaged the fuel tank siphoning or attempting to...
I want to know these things because I still have the intermittent issue with refueling, where refueling get's difficult to do from time to time. the pump clicks off. My best guess is that something small has snapped off in there and is getting moved around. When the snapped thing is in the wrong position the tank becomes difficult to fill. When it moves around the tank becomes easy to fill again. OR perhaps the leak at the top is creating some kind of weird vaccum on the system, causin g a difficult fill situation? But why wouldn't this happen all the time then, and not just some of the time? Maybe a check ball or valve is to blame, perhaps these two issues are separate the fuel leak and the difficult fill situation, or damage from a big impact in that are knocked some stuff out of whack. could an impact to the frame right there near the fuel tank do that?
What do I need to do? is it really bad to have fuel leaking off a vehicle? seems to be a really small leak, but will it only get worse with time? also can fuel destroy other things that it leaks onto? for instance if fuel spilled onto a brake line, could it cause it to leak? also what else should I do as preventative maintenance if I did pull off the tank to change the pump.There also that metal thing that the surrounds the fuel pump assy, protecting the exhaust from gas being shot all over the place. But I guess if this leak became bad enough, it could create more fumes which is more dangerous than fuel correct? Will this leak just get worse if unaddressed. How much can even a small fuel leak decrease fuel MPG?
What else should I do while the tank is down? I really want to be sure everything get's done right THE FIRST time. All I can think is it needs a new expensive fuel pump and maybe new fuel lines if there was contamination from some crap one of the dumbo last owners did? please help me. Thanks. What kind of mileage does all this crap go? seems like 100k used to be the mileage vehicles went, now it's 150k miles when all the parts start failing. Honestly might've been better to buy a vehicle with 200k miles that's has extensive service records, because then you know the PO had to fix all the crap that just . doesn't. last.
Oh yeah, any of you guys ever install a service hatch on the inside for the fuel pump? I was thinking about doing that. would need to be done right so it's air tight when closed though. This is also a Very small leak. IT's barley pushing leaking, but even a little bit of fuel has an extremely strong smell, and the fumes are getting pushed out. I wonder how much mpg I am loosing, and if I should just let this whole go until it's starts puddling fuel under the vehicle.
another picture here of the top of the fuel pump. I can't see it so I sure hope it uploads.
Last edited by neatchevy; Jan 4, 2026 at 12:57 AM.
I dropped the tank on my old s10 way back when... Then did it again a year later because I bought a junk fuel pump. When it came time to do the fuel pump on my Ranger I took the bed off instead of dropping the tank. That was much easier. If you were to put a removable panel in your van I think you would still have to drop the tank first to not go up in flames. Doing the cover right will also likely take welding and take more time than dropping the tank again when you already know how so I'd just drop it.
It seems most people on here that have fueling problems have motorhomes. I don't know if the regular vans have the same flapper. Keep an eye out for that when you drop the tank. I'd fix it sooner rather than later, but I could understand waiting until the weather is nicer and for sure drive it until the tank is empty. https://chevroletforum.com/forum/exp...r-neck-117008/
I was underneath the vehicle again. I filled my tank to 100% today from 75% no problem. I went underneath the vehicle and started seeing if I could maybe locate a loose line. As Soon as I started to move the return fuel line, fuel starting gushing out of the pump and dripping to the ground. what I thought was oil was actually fuel that had partially evaporated, meaning it had no smell and seemed oily. That is what it was.
Now something must be done. IF I got a multi tool to borrow from my family with a 1/2 moon blade, I think it would possible to cut an access cover with minimal sparks. Also first would be prep, cleaning the area of all wet fuel after letting it dry for a couple days and using a blower to push all fumes away. Then I would put aluminum foil or sheet metal tightly taped in between the work and the pump area. Would this work? Seems like it would be a heckuva lot easier to do this job. If by off chance it's a bad return fuel line, I would have to replace it. Would the heat alone cause an explosion? I was thinking maybe a large sheet of alumnium foil and then a big of sheet metal to cover the pump, then cut. I would also have a fan inside the van to push fumes outside first after extensive cleaning as best I can. The problem with that is I can't see the line the way they run it right next to the tank with the metal guard. I don't know if it free floats and how I would disconnect it without pulling the tank anyways. Once the job is done I would mount the old piece back on using screws with flat tops.
Any ideas then as to why it's leaking from up top? seems to be from feel that is is leaking from the fuel return line. it's like the line is loose or cracked. Any ideas on this? why is this so?
I don't have any problems doing this the right way of course, but If I was to drop the tank I would get an AC delco OE GM UNIT which costs $400. IF the fuel line is loose I might be able to get away with tightening it up. If the fuel line needs to be replaced then IDK about that one because Again I can't see the line the way it's routed with that metal guard there. IS it free floating and if it's not how are you even suppose to drop the tank if the line is fixed there. I guess I really need to know how to proceed and replace that line if need be. I guess the flapper unit is something that sits there near the filler neck. don't really need to drop the tank to see if that is the problem.
What about driving it until the fuel tank is empty? dangerous?
Which fuel pump do I need? the one with the sender unit?
intermittent trouble fueling
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