Fuel Pump Leak
 

Hello! New to this forum, hope I'm posting correctly.

Problem: Just bought an '04 Blazer. At very first fill up, began seeing fuel leaking immediately. Drove it home, seemed dry. If fuel gauge is correct, it's burning/leaking more than reasonable amount of fuel, to the tune of 1/2 tank in about 100 miles ... Dropped the spare tire. Engine running, sprayed a slow-evaporating solvent around the in-tank fuel pump. Seems there's a bit of a leak there. A small gurgle, some bubbling. Not enough to drip onto the ground.

My question, before shelling out $300 for a new pump: Common? Maybe someone banged the last pump in with a hammer/punch and missed, cracking the plastic that seems to be the most of the thing?

I searched the previous posts, best possibility I saw was a canister purge valve stuck ... but that wouldn't explain the consistent leak, methinks.

Any rate, it's got the standard 4.xliter V6, no Check Engine light on. 140K miles.

Anyone have an idea?

check the fuel lines coming off the pump could be one of those.

There is supposed to be a gasker between the fuel pump assembly and the fuel tank...from your description sounds like yours is either twisted, torn, missing, etc. Are the fill and vent hoses going to the tank tight or torn anywhere? As was suggested the fuel lines could be leaking at the connections...O rings may be missing, torn, etc.

Have you gone for a drive and then re-checked for wet fuel?

Keep us informed.

There should be an O-ring between the tank and the fuel pump/sending unit on the top of the tank. It can leak there - I've seen the 0-ring "expand" out of its groove (you can see it sticking out if yours has that problem) for some reason and a leak results. Not a leak when the pump is running, just a leak when the tank is full and the gas sloshes around enough to hit the top of the tank and leak out around the spot the 0-ring has moved. I've never had any luck getting an old 0-ring that has expanded back in that groove, just get a new one if that is the problem.

There shouldn't be enough movement to crack the hard lines coming out of the tank that connect to the flex line - but you can crack one trying to get those fitting loose if they are a little corroded and you twist them too much (seen that happen) and if that is the case you'll have to buy a new sending unit. If those lines are cracked and you have to drop the tank and install a new sending unit I'd advise getting a new pump as well. With 140,000 miles on it the pump will only last so much longer. That tank is a bear to get out if you're lying on the ground under a jacked up/blocked up Blazer (BTDT). The tanks are installed prior to the body going on so the hoses (vent) are so short they're hard to get hooked up again when you reinstall the tank.

We just did all that about 8 months ago and it cost right at $230 for the new pump and the new sending unit.

If its the tank leaking (corrosion around the straps is the usuall place) you'll need a new tank. I've patched tanks (up high) with those patch kits (some type of epoxy) but its not always successful.

Good luck with yours.

Folks,

Thank you for the responses. I *scored* on a Black Friday sale, and purchased the new fuel pump for 20% less! Ok, R/R'd the pump, upgraded the wiring harness (as per new pump instructions) and did a hard look at all hardware. Full tank of gas, 30 mile shake-down drive and re-check, all appears in good order. No leaks, seeps, anything. The old 'skirt' gasket/seal under the old tank appeared in good shape; seated and sealed correctly. All lines and connections good. The only explanation I get is that the housing itself had a crack (under pressure) that I could not see with the unit in my hand. No clues, but all looks good at this point.

The only thing I would offer folks in the future would be to keep the fuel filters fresh. The old fuel filter was absolutely clogged, which likely created additional work on the pump. That may have contributed to the problem.

I've been thru this Blazer bumper to bumper in the past 2 weeks; from brakes to minor tune-up and checking, checking, checking everything. Driving the shake-down was an absolute joy! Seems like a really decent vehicle.

Again, thank you for your replies. It's much appreciated!