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What happens if you overfill your engine with oil?
When I go to the gas station, I like to “top off” my tank, so I can get as much fuel in there as possible. My dad tells me this is a bad idea, and I could be damaging my car. Is it possible to overfill your gas tank?
R.E. Fulton · Updated on
Reviewed by Shannon Martin, Licensed Insurance Agent.
I hate to tell you this, but your dad is right! You can overfill your tank—and doing so could harm your car’s evaporative emission control system (EVAP), which controls
harmful emissions
when gas evaporates.You know that loud “thunk” you hear when you’re filling up, and it’s about done? That’s the pump telling you to stop pumping. Of course, it can be tempting to try to jam in a little more gas to hit that even number, but it’s so not worth it.
The EVAP is designed to work with gas vapors only. So when you overfill your gas tank, the liquid can cover the vapor intake hole and get sucked into the EVAP canister—damaging it and possibly other parts of the system.
If liquid gas gets into your EVAP system, it can cause your car to run sluggishly and even harm the engine. And that’s an expensive fix—depending on your make and model,
replacing an EVAP charcoal canister
can run from about $200 to more than $1,500.View full answer
- Gregory R.
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