Dealer Says That I Need a New Fuel Tank

Well, darn. I’d replace it. Most gas tanks for the last 20 years are plastic. Spoken by a guy who drills holes in scrap autos to drain their fluids. Steel tanks aren’t the norm anymore.

There is not enough oxygen in a fuel tank for ignition. There is an electric motor inside the tank, does that make you nervous?

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First, even with a metal tank, the issue is unlikely to cause a safety problem. Second, the most likely problem other than noise, would be if the untethered baffles hit the pump or other parts inside the tank. In other words, your kid could be out in the boonies making out with his girl when the car won’t start or you could be on I-95 doing 80mph when the engine dies. A good replacement tank costs less than $500 (Rock Auto has them). Can’t take more than 4hours to replace a gas tank, unless I am doing it. Ergo, an independent mechanic will save you at least $500.

That is if the shop will install the parts you purchased online. Independent shops often mark up part prices above manufacture MSRP. Also you must consider the other needed parts for the replacement of the tank.

Maybe that’s where you live. Around here Independents get discounts from the places I buy parts from and then mark them up from that price. Their final price is what I would pay for that part.

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I agree it would be really helpful to understand the answer to the question that Tester asked earlier:

How much gas was in the gas tank?
Because, if there’s a lot, nothing can rattle in the gas tank.

@MyMazda3:
Do you still hear the rattle when the tank is full?

Thank you.

Yes, most shops will add something to the parts cost, but if it is more than 15%, you need to find another repair shop.

Nevada_545
October 4

theStever:

Ergo, an independent mechanic will save you at least $500.

That is if the shop will install the parts you purchased online. Independent shops often mark up part prices above manufacture MSRP. Also you must consider the other needed parts for the replacement of the tank.

Just some food for thought. What if the rattle is not baffles in the tank? What if it’s baffles in the muffler?

Try banging around on the tailpipe and note if you hear any rattles. I would tend to suspect the exhaust rather than the tank but that is just a guess on my part.

Pic of the tank shows that the pump is offset to one side so if baffles are broken around the pump this should mean fuel starvation when cornering and gas sloshes to the sans pump side of the tank if the fuel level is very low.

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The reality is 30% to 50%, I have seen 100% markup. They may tell you the standard markup is 15% to sound honorable but that is not enough profit.

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I believe the OP misspoke claiming a baffle was making noise, more likely the heat shield mounts have broken from the tank.

It is unusual to find baffles in a fuel tank, they are unnecessary, the fuel pump is in a reservoir.

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It’s unlikely that the gas tank is made of materials that spark easily. But even with an ignition source, if there is even the smallest amount of liquid gasoline remaining in a capped “empty” tank the fuel-air mixture in the tank will be saturated, which for gasoline is above the upper explosive limit, so no ignition. (If you leave the cap off or actively pump air in there you might achieve a flammable or explosive mixture, but you’d have to be deliberate about it).

I’m not buying that it’s the baffles in the gas tank. I’m going to get other opinions on this from a couple of shops. It’s just not adding up and I don’t want to spend $1,500 guessing that the baffles in the tank are the problem.

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Smart move as suggested by me and others probably a heat shield or something it the exhaust system.

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It’s just my own experience that mufflers and loose heat shields are usually more likely to cause problems than fuel tanks on relatively “new” cars.

Mufflers/heat shields are also a lot cheaper to replace. That’s where I’d start.

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Update: I took the car to an independent mechanic. Indeed, it is the baffles in the fuel tank as everything else checked out. The shop didn’t know what to tell me regarding if this was a needed repair or not. They did say that if the baffle broke off and jammed my fuel pump, the car would obviously not run and need to be towed in and repaired (fuel pump, gas tank). They didn’t think there was a safety issue. Not sure that I want to spend the money on replacing the tank at this point.

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