Fuel leak from top of tank

eightshot627

Well-Known Member
My 2002, 4.2. 233k developed a leak from the top of the tank when it is running. I haven't dropped the tank yet. If it is going to require parts I'd like to have them on hand before dropping it. What would be the normal causes? From searching the net the metal lines from the fuel pump seem likely. The leak is running down near the removable cross member bolt.

What do you guys think?

Thanks,
Walt
 

MRRSM

Lifetime VIP Supporter
You know from your days in the United States Navy how much time and effort is dedicated to keeping Rust and Corrosion from eating the hulls right out from under The Fleet. If you live either in The Rust Belt or in Cold Clime Regions where Salting the Roads is the usual response to Snow, Sleet and Ice on roads and highways... that "Brown Cold Mung" as a Salty Brine will work its chemistry on Ferrous Metals in places under, within and on top of certain vulnerable under-carriage areas... causing Rust, Corrosion that can literally dissolve away Steel and Iron components.

If you look at the tiny "bathtub" that the Fuel Pump is nested inside of the molded Black Plastic Gas Tank ... you can well imagine all of that Salty Crap collecting, melting and eventually concentrating a lot of Salt and Water around all of those components. THIS is how bad it can get and FUEL LEAKS are inevitable:

RUSTEDOUTGMFUELTANK.jpg


@MAY03LT 's Video addresses How to Drop the Tank and R&R The Fuel Pump:


Using a Gastapper can make it easy to transfer the fuel from your Tank...into another vehicle or into some approved 5 Gallon Fuel Tanks and lighten the weight of everything:


If your situation is as bad as the one in the image... Using a Spark-Free Brass Drift Tool and Brass Hammer to dislodge the Locking Ring is the safest way to work around an Open Fuel Tank. The Mild Steel Lock Ring generally is NOT included with the purchase of either a DELPHI, ACDelco or BOSCH Fuel Pump and it will have to be ordered separately from RockAuto.

Prior to hammering that Rusted Ring loose... Using a stiff Bristle Brush in combination with some Compressed or "Canned Air) to clear away the Dirt, Junk and Rust from around the Flange will help to avoid dropping a lot of that stuff down inside of the Fuel Tank.

If you have to poke a Flashlight down inside there for any reason... use an Explosion Proof version available on Amazon for around $30.00.

https://www.amazon.com/dp/B007RKKEQQ/?tag=elightbars-20

EXPLSIONPROOFLITE.jpg

If you believe the tank is contaminated and has to be thoroughly washed out ...this DELPHI Video addresses how to perform the task:

 
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eightshot627

eightshot627

Well-Known Member
Lots of rust up here on the mountain. The road I live on was gravel/mud that coated the salt on and locked it to the metal. I keep a roll of brake line on the shelf. That picture is what I'm expecting to find. I've done plenty of fuel pumps and always wondered why they don't include the locking ring. My 2001 Tahoe's ring just crumbled when I removed it.
Mrs. eightshot627 reminded me I have a inspection camera so next opportunity I plan one sticking that up there to verify.
 

NJTB

Well-Known Member
You might want to look into getting new fuel lines too. Mine were rusted and unusable.
 

Matt

Silver Supporter
I did mine about mid last year and @MRRSM nailed it. If you can smell fuel, it's definitely the pump rusting out.

Make sure the tank it empty, buy a new locking ring (I didn't and probably should have) and have fun putting the plug back into the pump...it took me about an hour to get that in and I still have the scar on my arm from rubbing against the frame.
 
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eightshot627

eightshot627

Well-Known Member
I tried to get the camera up there but the lens kept get gunk on it so I quit. I found a 10% Rockauto code so pump, lines, ring and filter.

Now after the 4wd worked twice on Saturday. Sunday I got blinking 4hi and service 4wd. P0379. I just replaced the front actuator this in September. Ugh
 

MRRSM

Lifetime VIP Supporter
A Wise Man once said... "If you Have to Eat an Elephant... The Best Way is to Enjoy it... Is One Bite at a Time..." :>)
 
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eightshot627

eightshot627

Well-Known Member
The top of the fuel line bungs rotted off the sending unit. Cleaning the top with an air hose, the air blew fuel out of the lines while they were still connected. The only issue was I broke a evap canister connector. Luckily I'm a pack rat and had a piece of evap hose from my Tahoe that I spliced in. New pump in no leaks, it should improve my fuel mileage lol.

Thanks All!
 

Attachments

MRRSM

Lifetime VIP Supporter
Congrats on being Clever ...and Hanging on to Assorted Parts & Pieces... So Nice Rescued Hose Fix on your Fuel Tank during this R&R:

If you decide that you do not want to start another 4HI Thread... Here is a Good Sampling of the subject matter already discussed here at GMTN you can bounce through for answers:

https://gmtnation.com/forums/threads/4wd-not-working-step-inside.106/

https://gmtnation.com/forums/threads/no-4hi.11910/

https://gmtnation.com/forums/threads/stuck-in-4hi-but-not.17915/

https://gmtnation.com/forums/threads/weird-4wd-issue-stuck-in-4hi.9448/
 
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eightshot627

eightshot627

Well-Known Member
Thread 17915 is mine. I changed both the front actuator and the encoder. Unfortunatly or fortunately the 4wd fixed itself. It didn't work Sunday-Tuesday, worked just fine Wednesday and Thursday. It's hard to troubleshoot when the thing works.
 

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