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Engine Left On....While Refueling?

01din

NAXJA Forum User
Location
Virginia
Since our engines reach their highest temperatures immediately after they are shut down and the cooling systems are stopped - therefore making short idles less damaging to the engine than frequent on-and-offs - does anyone leave their engine on while refueling?

I know for newer cars, the entire fuel system is pressurized, including the tank, and will cause engine alerts if the cap is even removed while the engine is running.

It sounds a little extreme, but won't it help the long-term care of our engines?

PS - I dont do it....yet!

Thanks


David
'99 4.0, 145k miles
 
As you said, open the cap on a late-model while running, and it'll probably throw a code. Other then that, it won't hurt anything. 'Not sure it would make a huge difference. Unless you do a ton of highway driving, you probably have 20 or 30 stop/start cycles per tank full(or more) I don't think adding/subtracting one cycle per tank would make a difference.
 
I do both and no problems either way. If its hot out I leave it running so its nice and cool when I get back in.
 
if it takes very long to fuel up then you need to turn off your ac compressor because long idles will cause the compressor to get hot and make lots of noise. either turn off compressor or idle it up to bout 1200 rpm to get some air flowing through the condensor
 
as a firefighter, I'm supposed to tell you to turn off your engines while fueling with gasoline. (diesel gets a little leeway due to the different ignition temperatures, combustible vs flammable, yadda yadda). but, I hate that heat soak my 3rd injector gets! I've been leaving it running while I go into the local convenience store and the sub shop, too.

How about putting in a manual switch (or delay timer) for your electric fan? That should help lower the temperature a bit. I'm going to do that (both a manual switch AND a delay timer) for the new electric fan I've got on order. That, plus lebaron hood vents. :)

oh, if you do decide to leave your Yeep running while doing quick stops, I suggest a hide-a-key inside one of the bumpers or a spare key in your wallet. I have a key hidden "somewhere" under my XJ and a keyfob in my pocket.
 
The engine isn't gonna get any hotter while it's off. I think the risk with leaving it running is static buildup. Static can and does cause gas fires!!
 
The engine isn't gonna get any hotter while it's off. I think the risk with leaving it running is static buildup. Static can and does cause gas fires!!

It does get quite a bit hotter when the engine is off. I have a mechanical temp gauge. If the engine is idling.. and the temp is 190, I can turn the engine off, let it sit 5-10 mins, come back and crank it, and it will be at 200-210.
 
the engine may not generate heat itself, but the stupid pre-cats on the downpipes put off a ton of heat! Well, that's their job, burn off the unused fuel... which produces heat. That's why my engine temp will climb to 240 after I shut it off at 210, got a soda from the local 7-11 and started it back up.

It's 9am and already 88* outside, hopefully when I get up at 4pm to get ready for work, it won't kill me to run the engine for a bit to aim my infrared temp gun at the precats and see how hot they get.
 
As the sign says:

Turn off engine
No Smoking

It does not say:

No Smoking (because it's bad for you)
Turn Off Engine (unless you own an XJ and you're worried about heat soaking your #3 injector, if so it's OK)

...I'd just hate to be the guy that blew up the whole station because I couldn't follow a simple directive.
 
Good idea about the manual switch for the fan.

And I do have LeBaron hood vents that I havent installed yet - I'm still worried about the long-term effect of rain and snow, and installing drip pans would largely negate the cooling power/surface area....

Thanks for the ideas.
 
I'm sure that heat rises after you shut the engine off, but to assume from that that it's harming the engine is a bit of a stretch. Are you going to argue that you should always leave it running? How long a rest justifies shutting it down? Unless you have a heat soak problem or a cooling system problem (or maybe a spinnning turbo that requires idling down), a normal engine should be unbothered by the temporary rise in heat, and there are some who might contend that it will run more efficiently when near the top of its heat range anyway. Hybrid design centers around the idea of constant hot shutdowns and restarts, and they seem to handle it pretty well.

I think if you're worried about the effect of shutting down your engine when you refuel, you probably should fix the engine.

I remember years ago a local gas station owner who, obviously partly as a gesture, smoked whenever he ran the pumps. He would conspicuously put his burning cigarette on the top of the pump. Of course nothing ever happened, nobody ever blew up, etc., but I'm not sure that was a gesture of sufficient statistical significance to argue that we should all smoke when we fill our tanks.
 
I remember years ago a local gas station owner who, obviously partly as a gesture, smoked whenever he ran the pumps. He would conspicuously put his burning cigarette on the top of the pump. Of course nothing ever happened, nobody ever blew up, etc., but I'm not sure that was a gesture of sufficient statistical significance to argue that we should all smoke when we fill our tanks.

the local owner of the staion in my town would check your oil once a month and always wash the windsheild, with the smoke hanging out his mouth, when getting a 20$ fill-up.
 
All the gas stations in this area would freak if you left it running while refueling. I even had this lady yell at me because I was filling gas cans in a trailer instead of on the ground.
 
I think if you're worried about the effect of shutting down your engine when you refuel, you probably should fix the engine.


The engine is designed to operate at an idea temperature, and a significant increase in heat (30-40 degrees) without mechanical cooling will certainly increase metal fatigue and decrease the life of plastic/rubber parts of the engine bay. This just means that keeping the engine from reaching those temps often will keep it "running" (ie, component lifespan) longer....

FYI I drive mostly highway miles, but almost always pop my hood until the engine cools after a drive of more than 30 minutes to relieve the heat buildup. It sounds anal-retentive, but beyond good maintence of my engine, I'm amazed at how well my XJ has handled its nearly 150k miles.

Good discussion -


David
 
As the sign says:

Turn off engine
No Smoking

It does not say:

No Smoking (because it's bad for you)
Turn Off Engine (unless you own an XJ and you're worried about heat soaking your #3 injector, if so it's OK)

...I'd just hate to be the guy that blew up the whole station because I couldn't follow a simple directive.

:thumbup: Wonder why those signs say that? Duh. One of the few posts that makes any sense. Think about it.
 
I'm more afraid of causing a fire by idling my jeep and letting it drip oil/tranny fluid onto the exhaust than I am of causing a fire by idling my jeep and having static light the gas pump on fire.
 
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