Facts or opinions on topping off gas tank

The risk may be low but the reward in most cases is lower.

 

I had to replace my charcoal canister. Cost me $300 or $400(can't remember)for a new one. I don't top off as aggressively as I used to. I had a Chrysler 300 that suffered the same problem. It's a real pisser and kinda unbelievable that pumping too much gas in your tank will break shit.

 

I top mine off 10-12 litres extra usually.

 

X2

 

I bought a used 07 Xterra in 2011 that the previous owner topped off all the time and ruined the charcoal canister. It was around $500 to repair. I never top off or even click to round ff, it's not worth the risk for the very little gain IMO.

I yelled at the gas attendants in Oregon when they'd keep clicking it to a round number, I couldn't care less if my gas is $27.64 instead of $28.00.

 

The EPA realized that overfilling the gas tank can damage the EVAP system thereby producing more emissions so they demanded the auto makers devise a method to prevent that from happening. So the auto manufacturers came up with the RO/OF valve. ROLL OVER/OVER FILLING valve. This is a ball in a cage with a weight at the bottom at the end of the fill tube. When filling the gas to the full level in the tank the ball floats up and blocks the fill neck thereby shutting off the gas nozzle. And no matter how much you try you can't overfill the gas tank because the ball prevents gas from being introduced the nozzle keeps shutting off. In the event of a roll-over accident, the weight under the ball forces the ball against the end of the filler neck thereby preventing gas from running out of the gas tank. The EPA doesn't want unburned gas in the air, in the water, or on the ground.

 

You guys read this tread - canister - $300, $400, $500 - and you still want to top off - must have Benjamin's burning a hole in your pocket - CFS.

 

I did it to my TL for almost 5 years with no issues.

 

I drive a lot, like almost 800 miles a week, I top off to the nearest dollar, just to be safe. Don't have Benjamin's burning a hole in anything.

 

So how does this problem manifest?? Does it trigger a code. Does it actually effect the running of the truck? Does it effect the ability to pass emissions testing? How do people know their canister is ruined?

 

How do you know if your charcoal canister craps out? Does it create an immediate issue?

 

IIRC, it manifested as a CEL in my buddy's truck and caused rough running until he replaced it.

 

CEL turns on. I didn't notice any rough running condition in the Tacoma, but the 300 would not start the first time you turned the key.

 

And neither do I for that matter. Basic rule for me is that once it clicks I'm done. I heard years ago that topping off introduces more gas vapor into the atmosphere and unburned gas vapor is a worse global warming impact than vehicle exhaust. Plus it's a waste, gas I'm paying for evaporating out of the filler neck. I do however slow down the flow once I know it's within a gallon of full. When I stop to get gas I look at the gauge. It's not rocket science to figure out a pretty good estimate of what it's going to take. Start fueling with the hold open clip wide open. Once it gets close I move the hold open clip to the lowest flow setting. Pump shuts off, replace nozzle in pump, take receipt, reset trip odometer A, drive the fook away.

 

I have found you can safely top off by waiting 30 seconds after the shut off then pump another .1-.2 gallons till it shuts off again. Its not much

 

My guess is that the perfect storm is a severe overfill + warm temps + little or no driving after the fill. I guess I have never hit that trifecta, but I learned something today. I'll be more thoughtful about this in the future.

 

Attendant topped mine off a few years ago... sent fuel into the charcoal canister and tripped a cel dash light. Got it fixed at the dealer. They warned about the canister needing replacement if it keeps happening.... not cheap.

 

Filled it way too much earlier this year. I was going on a long trip and rather than hit the gas station before leaving, I filled up with what was left in my gas can, It bubbled out the neck of the filler. Thankfully no CEL or other issues so far.

 

Considering how your rig is setup for being off road... why no Rotopax or Jerry cans?

Much cheaper than replacing charcoal canister.