Gas tank leak at fillup?

Gentlemen you have helped me on a few different issues on my Coronet.

Here are a few links if interested in the history of the issues.

http://www.forbbodiesonly.com/moparforum/showthread.php?t=36256
http://www.forbbodiesonly.com/moparforum/showthread.php?t=36726

So I have replaced the Fuel tank, Sending unit, Vent lines, Fuel lines to pump, the fuel pump and lines from pump to carb.

The main problem with the fuel system was the tank was full of rust I mean allot of rust the sending unit was rusted solid.

So after replacing the entire fuel system except the carb, I add some fuel from a can to get me to the local station and fill the tank.

When I filled the tank everything was normal and I could fill the tank at full speed for the first time no more 1/2 gallon a time and let it drain down the neck and repeat.

But I did overfill it a but as it spit it out the neck a little and while I was wiping the quarter panel off I notice a small drip from the neck area.

I figure no big deal it was a small drip and I was a block from home so I drove it home with out incident.

I go on duty and 12 hours later I come home and no more leak but there is a 4 foot wet spot under the car?

I can't see where it would have leaked from?

It is not leaking not and I assuming that the fuel level is below where the leak is?

Did I just overfill it or should I being looking for something else?

When you replaced the tank did you replace the grommet for the filler neck or reuse the old one? I wouldn't think you would have a 4 foot puddle under the car UNLESS you parked it with the front end of the car elevated higher than the rear. If it was parked level then I sincerely doubt the the grommet is to blame though.

Is your venting tube setup correctly? Where is the center of this 4 foot spot? What is directly above it assuming it was parked level?

Mine did the same thing. I got a new grommet from my local dodge dealer. It worked great. I still have a drip at fill up but it is because of my dry rotted hoses needing replaced.

I usually set the pump on full flow and walk away. When it clicks off I am done.

agreed with the guys above - I have the same problem and have narrowed it down to just the cap. I was wondering where to get it though, so thanks, jim bob like you, my entire fuel system is new.

HT413 said:

agreed with the guys above - I have the same problem and have narrowed it down to just the cap. I was wondering where to get it though, so thanks, jim bob like you, my entire fuel system is new.

Click to expand...

Was the car sitting in the sun or was it a hot day? Remember that you will get expansion when the fuel heats up. If it was that full, that may have been your problem.

dave, for me, i bought it a month or two ago and had it transported home on an 18 wheeler car carrier. it was sitting on a pretty steep incline on the back of the carrier and the driver noticed it and told me about it. it hasn't leaked since, but it has never been above half a tank since i got it.

Gentlemen,

The puddle was centered around the neck area of the car, It was a very hot day 104f and I am pretty sure I overfilled it, I have not noticed a leak since then so I will keep an eye on it but I think it was the perfect storm of overfill plus hot day.

We will see. Thank you for the replies

Off topic but fuel related. I have owned the 69 Coronet since 1988 and have never filled it without spilling. Ever. For a while if you parked on a grade nose down, fuel would seep out of the top forward part of the tank. Vent related. Eventually extended the tube that goes into the trunk HIGHER. Problem solved.

Gas fumes can be a pia. Even when the tank was replaced after being jerked around on the phone by Mopar Ed in the Central Valley, the vent tube with the loop in it was a problem.