Leak origin - The 1947 - Present Chevrolet & GMC Truck Message Board Network

iufan71 · 07-18-2003, 11:53 PM

Turned my 78 GMC truck off today,and got out,and noticed a leak comeing from the gas tank(passenger side tank) dripping off the bands that are around the gas tank that holds the tank in place. It appears to be oil i think. Does anyone have any idea where it might be coming from before i try tracking it down? Thanks. Heath

**swervin ervin** · 07-19-2003, 12:06 AM

It's not oil. No oil up there. I think what it would be is gas leaking from the tank. Behind the tank straps, there are pieces of asphalt looking stuff, sort of like roofing felt. This is supposed to keep the straps from rubbing a hole in the tank. I think the gas is getting on the asphalt and desolving it. This would look like oil.

That's my guess.

iufan71 · 07-19-2003, 12:08 AM

Yeah,i have smelled gas lately. I had no idea how any oil would be all the way back there either,but figured i would look like a dummy and ask. Ok,so my tank is leaking..where is the best place,and not too pricey to get a new tank?

MylilBowTie · 07-19-2003, 12:11 AM

I would check the valve covers, oil pan and possibly the rear main seal for the crankshaft. If it is motor oil on the tank it would have to be coming from the engine. It would be leaking somewhere and flying back when its driven at speed 35 and up.

One other thing I could think it might be is transmission fluid. What is the color and smell? Color is more important than anything, smell is just another part of it.

Dooohhh :got beat to it: lol

AirMale · 07-19-2003, 04:33 PM

There's a guy on ebay that sells new 16 or 20 gallon tanks. I just got one for $60+$12 shipping.

iufan71 · 07-19-2003, 11:45 PM

I just got one from Advance for $99. Should be here monday. I asked my friend if it was hard to put them into this truck,and he said just be sure get some extra fuel line cause its hard to get your hand back up above the tank. I guess he meant to reattach the fuel lines. This seems like a fairly easy job to me. But any tips are appreciated,as i plan on changing tanks on monday or tuesday.

07-18-2003, 11:53 PM	#1
iufan71 Registered User Join Date: Apr 2003 Location: Indianapolis,IN Posts: 138	Leak origin Turned my 78 GMC truck off today,and got out,and noticed a leak comeing from the gas tank(passenger side tank) dripping off the bands that are around the gas tank that holds the tank in place. It appears to be oil i think. Does anyone have any idea where it might be coming from before i try tracking it down? Thanks. Heath

07-19-2003, 12:06 AM	#2
swervin ervin You get what you pay for Join Date: Dec 1999 Location: Cherryville, NC Posts: 4,798	It's not oil. No oil up there. I think what it would be is gas leaking from the tank. Behind the tank straps, there are pieces of asphalt looking stuff, sort of like roofing felt. This is supposed to keep the straps from rubbing a hole in the tank. I think the gas is getting on the asphalt and desolving it. This would look like oil. That's my guess. __________________ Mike 1985 Chevy C-10

07-19-2003, 12:08 AM	#3
iufan71 Registered User Join Date: Apr 2003 Location: Indianapolis,IN Posts: 138	Leak Orgin Yeah,i have smelled gas lately. I had no idea how any oil would be all the way back there either,but figured i would look like a dummy and ask. Ok,so my tank is leaking..where is the best place,and not too pricey to get a new tank?

07-19-2003, 12:11 AM	#4
MylilBowTie Right turn Clyde Join Date: Nov 2002 Location: Cincinnati, Ohio Posts: 2,911	I would check the valve covers, oil pan and possibly the rear main seal for the crankshaft. If it is motor oil on the tank it would have to be coming from the engine. It would be leaking somewhere and flying back when its driven at speed 35 and up. One other thing I could think it might be is transmission fluid. What is the color and smell? Color is more important than anything, smell is just another part of it. Dooohhh :got beat to it: lol __________________ 1974 C25 LWB: 454 4bbl Carb / TH400 / 3.73 1992 Camaro RS 305 TBI

07-19-2003, 04:33 PM	#5
AirMale Senior Member Join Date: Jan 2003 Location: Atlantic City, NJ Posts: 1,073	There's a guy on ebay that sells new 16 or 20 gallon tanks. I just got one for $60+$12 shipping. __________________ 86 SWB 9.0 LITER T-400-OD 4.11 eaton-4/5 drop Best 1/4 12.51 @112mph no traction

07-19-2003, 11:45 PM	#6
iufan71 Registered User Join Date: Apr 2003 Location: Indianapolis,IN Posts: 138	Gas Tank I just got one from Advance for $99. Should be here monday. I asked my friend if it was hard to put them into this truck,and he said just be sure get some extra fuel line cause its hard to get your hand back up above the tank. I guess he meant to reattach the fuel lines. This seems like a fairly easy job to me. But any tips are appreciated,as i plan on changing tanks on monday or tuesday.



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