Gas tank overfill - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Old Radio Tech · 02-08-2018, 03:36 AM

This has happened more than once now. Filling my regular gas filler tube using an unleaded gas nozzle. The unleaded kickoff allows gas to come up the tube too far resulting in an overflow out the channel on the top of the tank on the passenger side to ground. Been filling with the nozzle on the slower fill notch. User the faster filling notch or find an unleaded insert for the filler tube???

**Palf70Step** · 02-08-2018, 10:21 AM

These old trucks don't have baffles in them to prevent back splash. My 64 would do it if I filled it fast as the waving motion of the fast fuel flow bounced around in the tank. The tube from the filler is not very long as compared to more modern vehicles, so when the back splash gets going you are normally almost to the top of the tube.

If you are leaking out the top of the tank on the passenger side, it also sounds like you got something wrong with your tank, or the maybe the seal where you tank float goes in.

**jayoldschool** · 02-08-2018, 11:07 AM

Quote:

resulting in an overflow out the channel on the top of the tank on the passenger side

You need a new gas tank. Immediately.

**The Rocknrod** · 02-08-2018, 11:38 AM

Why would you have gas spilling on the passenger side again?

Old Radio Tech · 02-08-2018, 01:08 PM

There is only one hole in the top of the tank. The sending unit and the output use that hole. There is a groove that is part of the tank that goes from this hole to the passenger side of the tank. Any overflow or leakage uses this channel and drains to ground from there. So because the kickoff allows gas to fill up the tube too far the overall level is above the top of the tank and is finding a way out at this hole. It appears to be coming out around the sending wire connection. Ordering a new sending unit today and maybe a tank once I get it dropped and inspected.

**Palf70Step** · 02-08-2018, 01:27 PM

Get a new O-ring for the sending unit

02-08-2018, 03:36 AM	#1
Old Radio Tech Registered User Join Date: Dec 2016 Location: Anchorage Alaska Posts: 74	Gas tank overfill This has happened more than once now. Filling my regular gas filler tube using an unleaded gas nozzle. The unleaded kickoff allows gas to come up the tube too far resulting in an overflow out the channel on the top of the tank on the passenger side to ground. Been filling with the nozzle on the slower fill notch. User the faster filling notch or find an unleaded insert for the filler tube???

02-08-2018, 10:21 AM	#2
Palf70Step State of Confusion! Join Date: Jul 2002 Location: Gulfport, MS USA Posts: 47,322	Re: Gas tank overfill These old trucks don't have baffles in them to prevent back splash. My 64 would do it if I filled it fast as the waving motion of the fast fuel flow bounced around in the tank. The tube from the filler is not very long as compared to more modern vehicles, so when the back splash gets going you are normally almost to the top of the tube. If you are leaking out the top of the tank on the passenger side, it also sounds like you got something wrong with your tank, or the maybe the seal where you tank float goes in. __________________ Bill 1970 Chevy Custom/10 LWB Fleetside 2010 Toyota Tacoma PreRunner SR5 Double Cab - DD Member of Louisiana Classic Truck Club (LCTC) Bill's Gallery Life isn't tied with a bow, but it's still a gift. Live simply. Love generously. Care deeply. Speak kindly. Leave the rest to God!

02-08-2018, 11:38 AM	#4
The Rocknrod Moderator Join Date: Aug 2011 Location: China Spring, TX Posts: 7,280	Re: Gas tank overfill Why would you have gas spilling on the passenger side again? __________________ Master Chief, US Navy, Retired 1964 C10 Step-side Short Bed - In Progress 2009 2500HD Duramax LTZ 1948 GMC Panel 1956 Big Window Stepside 1953 5 Window Chevy Stepside 1932 Coupe New Seat Foam for Bench Seats?

02-08-2018, 01:08 PM	#5
Old Radio Tech Registered User Join Date: Dec 2016 Location: Anchorage Alaska Posts: 74	Re: Gas tank overfill There is only one hole in the top of the tank. The sending unit and the output use that hole. There is a groove that is part of the tank that goes from this hole to the passenger side of the tank. Any overflow or leakage uses this channel and drains to ground from there. So because the kickoff allows gas to fill up the tube too far the overall level is above the top of the tank and is finding a way out at this hole. It appears to be coming out around the sending wire connection. Ordering a new sending unit today and maybe a tank once I get it dropped and inspected.

02-08-2018, 01:27 PM	#6
Palf70Step State of Confusion! Join Date: Jul 2002 Location: Gulfport, MS USA Posts: 47,322	Re: Gas tank overfill Get a new O-ring for the sending unit __________________ Bill 1970 Chevy Custom/10 LWB Fleetside 2010 Toyota Tacoma PreRunner SR5 Double Cab - DD Member of Louisiana Classic Truck Club (LCTC) Bill's Gallery Life isn't tied with a bow, but it's still a gift. Live simply. Love generously. Care deeply. Speak kindly. Leave the rest to God!



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