Some useful tips for gassing up at the Pumps
01-14-13, 11:04 AM
#1
Lexus Fanatic
Thread Starter
Some useful tips for gassing up at the Pumps
Most full-service gas-stations have gone the way of the dinosaurs (I generally prefer self-serve myself, for a number of reasons), so, in most cases, you will probably have to do the refilling yourself. Here's a couple of time-honored tips I've discovered myself over the years (and/or have read about) to make that process as safe as posssible, and to avoid as much damage to the car's paint/trim and components as possible.
1. With a stock or unmodified engine, generally use the grade of fuel recommended in the Owner's Manual. Some newer turbos and high-compression engines recommend mid-grade or premium (91/93 octane) but allow regular (87).....the engine computer will retard the spark for regular to avoid pinging, and HP/Torque may be slightly less, but virtually unnoticeable. But if it says premium or regular REQUIRED, then use that grade as necessary....the engine's designers have put that requirement in there for a reason. Using premium in a regular-rated engine won't necessarily give you any more benefits...and will cost more to fill up. Conversely, using regular when the engine requires premium can cause pinging or excessive spark-retadation to compensate, adding to engine heat and noticeably lessening power. It's true that premium-grades of gas often (but not always) have more engine-cleaning detergent-additives than regular, but the added octane, in an engine designed for regular, can cause hard-starting and other problems.
2. If possible, DON'T gas up when the big 18-wheeler tanker is in the station filling the underground tanks. Particularly with older and dirty tanks, that can be a problem if the big fuel-hoses on the truck, with their strong pressure, stir up the dirt and sediment at the bottom of the tank. The gas pumps are supposed to have auxiliary filters to catch these particles at the last minute before they get into your car, but if they are clogged or in poor condition those particles just go right into your fuel-tank, where they can be sucked up by your car's fuel-pump, clog up your own fuel system, and cause all kinds of drivability problems. Then, of course, you'll need a complete fuel-system cleaning...which can cost money. Usually, just waiting five minutes or so after the tanker has stopped filling the underground tanks (if you don't have a bunch of angry, impaitient drivers in line beind you) will allow the dirt to settle back to the bottom of the underground tanks, where it probably won't be sucked up into your own car. If those guys behind you are so impaitient, then let them screw up their own tanks.
3. Opinions differ on this, but I generally recommend national name-brand fuels (especially Shell and Chevron) over El Cheapo Smiling Sam's gas station down the street. True, gasoline is gasoline (its chemical and molecular formula/composition is determined by Federal law), and comes from the same sources/refineries. But, in general, the big name-brands (particularly Shell and Chevron) have more (and better) detergent-additives than the budget-brands, and will generally keep your engine and fuel-system cleaner. As I see it, it makes little or no sense to use cut-rate gas, save a little money up front at the pumps, and then just have to turn around and spend the money you just saved at the pump on engine fuel-system cleaners (or risk the engine stalling in traffic).
4. When actually filling up, I notice many people just yank the filler-nozzle in and out, allowing gas to drip or run down from the nozzle onto the car's paint/sheet-metal and trim. My strong recommendation (and I do this each time myself), is, after you have opened the gas filer-door and taken the cap off (some newer Ford products don't have conventional caps, but a dfferent sealing-system), rotate the nozzle so that the open end of the nozzle points upward, fit it over the open end of the gas-pipe, and then rotate it downward so any gas trapped in the nozzle will run down the pipe where it belongs, not onto your car's paint. (if you do get stains in the paint from dried-gas, SCRATCH-OUT liquid, which I highly recommend, can often get them out). When removing the filler-nozzle, rotate it again coming out so that it comes out of the gas-pipe pointed up, and then simply hang it back onto the gas pump.....that will keep the rear fender of your car clean and neat.
(This procedure will sometimes be more difficult, but not impossible, with the big rubber nozzle-covers in use with some gas pumps...they have a tendency to be spring-loaded and difficult to keep in place).
5. Assuming you don't just take the trip-computer's figure for your fillup-to-fillup mileage (those trip computers are sometimes right-on and sometimes up to 2 MPG off), you will usually get a more accurate fill-up if you do it on a level and no-bank platform. A side-to-side or front/rear tilt in the car's stance can cause the automatic cut-off on the nozzle to go off early...or late, and underfill or overfill the tank.
6. Last, after the nozzle does shut off automatically, don't keep adding fuel in an attempt to top off things as much as possible. It might add a slight amount to your potential cruising-range, but the raw gas can overflow and, besides running down the side of the car (which I've already covered above), or seep into the charcoal-canister which helps control evaporative-emissions and damage it. That could trigger a CHECK ENGINE light....as could undertightening the gas cap, which should usually be tightened till you hear audible clicks, and no more. An overly-loose or overly-tight gas-cap can trigger a CHECK-ENGINE light by allowing gas fumes to seep past the seal. In many states, where emissions-tests are required, when that light is on, a vehicle will not pass....that's usually the first thing they check.
1. With a stock or unmodified engine, generally use the grade of fuel recommended in the Owner's Manual. Some newer turbos and high-compression engines recommend mid-grade or premium (91/93 octane) but allow regular (87).....the engine computer will retard the spark for regular to avoid pinging, and HP/Torque may be slightly less, but virtually unnoticeable. But if it says premium or regular REQUIRED, then use that grade as necessary....the engine's designers have put that requirement in there for a reason. Using premium in a regular-rated engine won't necessarily give you any more benefits...and will cost more to fill up. Conversely, using regular when the engine requires premium can cause pinging or excessive spark-retadation to compensate, adding to engine heat and noticeably lessening power. It's true that premium-grades of gas often (but not always) have more engine-cleaning detergent-additives than regular, but the added octane, in an engine designed for regular, can cause hard-starting and other problems.
2. If possible, DON'T gas up when the big 18-wheeler tanker is in the station filling the underground tanks. Particularly with older and dirty tanks, that can be a problem if the big fuel-hoses on the truck, with their strong pressure, stir up the dirt and sediment at the bottom of the tank. The gas pumps are supposed to have auxiliary filters to catch these particles at the last minute before they get into your car, but if they are clogged or in poor condition those particles just go right into your fuel-tank, where they can be sucked up by your car's fuel-pump, clog up your own fuel system, and cause all kinds of drivability problems. Then, of course, you'll need a complete fuel-system cleaning...which can cost money. Usually, just waiting five minutes or so after the tanker has stopped filling the underground tanks (if you don't have a bunch of angry, impaitient drivers in line beind you) will allow the dirt to settle back to the bottom of the underground tanks, where it probably won't be sucked up into your own car. If those guys behind you are so impaitient, then let them screw up their own tanks.
3. Opinions differ on this, but I generally recommend national name-brand fuels (especially Shell and Chevron) over El Cheapo Smiling Sam's gas station down the street. True, gasoline is gasoline (its chemical and molecular formula/composition is determined by Federal law), and comes from the same sources/refineries. But, in general, the big name-brands (particularly Shell and Chevron) have more (and better) detergent-additives than the budget-brands, and will generally keep your engine and fuel-system cleaner. As I see it, it makes little or no sense to use cut-rate gas, save a little money up front at the pumps, and then just have to turn around and spend the money you just saved at the pump on engine fuel-system cleaners (or risk the engine stalling in traffic).
4. When actually filling up, I notice many people just yank the filler-nozzle in and out, allowing gas to drip or run down from the nozzle onto the car's paint/sheet-metal and trim. My strong recommendation (and I do this each time myself), is, after you have opened the gas filer-door and taken the cap off (some newer Ford products don't have conventional caps, but a dfferent sealing-system), rotate the nozzle so that the open end of the nozzle points upward, fit it over the open end of the gas-pipe, and then rotate it downward so any gas trapped in the nozzle will run down the pipe where it belongs, not onto your car's paint. (if you do get stains in the paint from dried-gas, SCRATCH-OUT liquid, which I highly recommend, can often get them out). When removing the filler-nozzle, rotate it again coming out so that it comes out of the gas-pipe pointed up, and then simply hang it back onto the gas pump.....that will keep the rear fender of your car clean and neat.
(This procedure will sometimes be more difficult, but not impossible, with the big rubber nozzle-covers in use with some gas pumps...they have a tendency to be spring-loaded and difficult to keep in place).
5. Assuming you don't just take the trip-computer's figure for your fillup-to-fillup mileage (those trip computers are sometimes right-on and sometimes up to 2 MPG off), you will usually get a more accurate fill-up if you do it on a level and no-bank platform. A side-to-side or front/rear tilt in the car's stance can cause the automatic cut-off on the nozzle to go off early...or late, and underfill or overfill the tank.
6. Last, after the nozzle does shut off automatically, don't keep adding fuel in an attempt to top off things as much as possible. It might add a slight amount to your potential cruising-range, but the raw gas can overflow and, besides running down the side of the car (which I've already covered above), or seep into the charcoal-canister which helps control evaporative-emissions and damage it. That could trigger a CHECK ENGINE light....as could undertightening the gas cap, which should usually be tightened till you hear audible clicks, and no more. An overly-loose or overly-tight gas-cap can trigger a CHECK-ENGINE light by allowing gas fumes to seep past the seal. In many states, where emissions-tests are required, when that light is on, a vehicle will not pass....that's usually the first thing they check.
Last edited by mmarshall; 01-14-13 at 01:50 PM.
01-14-13, 02:05 PM
#6
Lexus Fanatic
Thread Starter
Thanks. 
Some of them I learned myself; some passed on from others.
Chevron's well-known Techroline detergent additive is considered by a consortium of automakers (GM, BMW, Honda, Toyota, and others) to be the Tier-1 industry-standard for fuel-system protection. So, of course, is BG44K fuel-system cleaner (and other BG products)...but BG products are only sent to service-shops....they (usually) aren't avalable to the public at large.
Shell's V-Power detergent additive also has a good reputation. Shell is very popular here in the D.C. area, partly because Chevron stations are few and far between here, and partly because the Giant Supermarket chain here gives bonus-points for gas-discounts at local Shell stations.
Sure...glad they helped. I didn't know the tanker-one either, until Pat Goss, the technician for TV's Motorweek show (some of you may watch Motorweek), mentioned it on one of his car-care sessions.
Some of them I learned myself; some passed on from others.
I've only ever used and will continue to only use Chevron.
Shell's V-Power detergent additive also has a good reputation. Shell is very popular here in the D.C. area, partly because Chevron stations are few and far between here, and partly because the Giant Supermarket chain here gives bonus-points for gas-discounts at local Shell stations.
Originally Posted by xsh0tya
Great tips helpful for folks who may have not known better. (I really didn't know the gas tanker truck one myself.)
Thanks!
Thanks!
I didn't know the tanker-one either, until Pat Goss, the technician for TV's Motorweek show (some of you may watch Motorweek), mentioned it on one of his car-care sessions.
01-14-13, 02:08 PM
#7
Lexus Fanatic
Thread Starter
Originally Posted by jbjones85
I personally follow everyone of those.
You will potentally have fewer problems over the life of your car. Sure....glad it helped.
One problem we (fortunately) don't have to worry about any more is the lead in gas fouling the spark plugs. That used to be a common problem, but ceased as American-market cars converted to leaded fuel in the 70s....and to breakerless electronic ignition about the same time, which made spark-plugs run hotter and burn off more of the lead/oil/carbon deposits.
Last edited by mmarshall; 01-14-13 at 02:15 PM.
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01-14-13, 05:03 PM
#8
Out of Warranty
My 2000 RX300 burned the "preferred" premium fuel, but ran fine most of the time on regular unleaded. The difference, I discovered, is common to many vehicles with sophisticated engine control systems - they may stumble a bit off idle with regular. The problem it seems is the fuel map stored in the ECU. Often it's "programmed" for premium, using a bit more spark advance to gain early power. Of course the knock sensor hears that first ping an dials back the advance, but sometimes in some cars (my first RX was one), it could cause a slight stumble off the line. For that reason, I used premium around town, and regular on long trips where hours at cruising speed out on the slab put few demands on the fuel map.
My 2004 RX330 was slightly different - while a bit unhappy with regular, a mid-grade fuel was perfectly fine. I guess it wasn't quite so finicky about octane. I burned a good mid-grade and never had a problem with hesitation on starts. In both cases, I seemed to get slightly better mileage with premium, but that's probably the old "butt dyno" talking. Usually large gas stations off the heavily-traveled highways, preferably outside the city to take advantage of minimal taxes will offer the best prices. Use your loyalty cards - either from your bank or local merchants to get the best discounts
As Mike says, gasoline is gasoline, the difference is in the additive package - and the care with which it's pumped from the depot and delivered to your station's tanks. Whatever brand you prefer is really up to you. Most major brands now come with adequate additives for your area and normally take good care of their tanks and plumbing. Find a good clean station with at least moderately new tanks and fuel islands, particularly those with lots of traffic. If there's some kind of funk in the tanks, at least it's being spread over a large number of users - you won't get it ALL. Good tip about not fueling during or for several minutes after a fuel drop - let the dirt settle back to the bottom. Unless the tank or the plumbing is cracked, water condensate shouldn't be a problem in your fuel. The ethanol in today's fuels will adsorb a fair amount of water and pass it trough your engine harmlessly.
I've been the victim of filthy fuel myself and learned to carry spare fuel filters in case I get a shot of dirt or granulated rubber with my gas. It's pretty evident - as the fuel flow begins to be restricted, you find you are unable to maintain highway speed. A quick filter change will fix the problem, but finding the proper one at 3am on a deeply rural highway is no fun. Carry a spare. If you are blessed with one of those filters at the intake of the fuel pump in your tank, you may be in for a rather costly "fuel module" change that requires dropping the tank. It pays to be a little picky about the fuel you buy.
Here's a tip or two I got from a client who manufactures tanks and fuel plumbing for gas stations all over the US. The API requires tanks and fuel plumbing to be identified by color. A red cover over the tank inlet (usually found out of traffic somewhere on the driveway where the fuel trucks drop their load) indicates the "premium" tank inlet, blue for a mid-grade fuel, and white for regular. Often these caps or covers will have a white or black cross on them. Fuel dispensers (pumps to you and me) nowadays blend premium and regular to arrive at their mid-grade product (check to see if you find the fillers for those underground tanks, so you may not see a blue tank filler, confirming your mix is being performed at the pump. If you use a mid-grade fuel, try to buy your gas when the driveway traffic is at a minimum. Here's why:
Normally a mid-grade mix is fine, but if there are ten cars on the driveway, four taking premium, four mid-grade, and two, regular, you may find that the mid-grade blend delivered by your pump is a bit on the "weak" side, a bit less than a 50-50 mix you expect, as the pressure drop from those premium customers can have a considerable effect on your fuel delivery. This is common with old buried rubber hoses that aren't really efficient delivery piping for gasoline. Sadly, that's probably the case on 90% of all gas islands in the US. If you thought your gas was being blended by volume, it's not - it's pressure-dependent and you can be getting less than you're paying for. When the state certifies the pump, it's looking at total delivery at the nozzle, not how that mix is blended in the pump. There's no real control of that - except by the pump drawing the mid-grade fuel from a separate underground tank. It's perfectly legal, and most retailers don't want to mess with the extra tank and plumbing - but a few do. It's pretty much up to the individual operator.
BTW there are a couple other color codes that you may or may not find on the tank fill pipes during your inspection - diesel will be yellow, or yellow with a blue stripe (low sulfur diesel), biodiesel will be brown with a yellow rim, heating oil, green, and kerosene, gray. You should be able to see a color chart from the fill area, or at least posted on the wall inside the station office. A blue cap means your mid-grade is always going to be a proper blend, whatever the state of traffic on the driveway.
My 2004 RX330 was slightly different - while a bit unhappy with regular, a mid-grade fuel was perfectly fine. I guess it wasn't quite so finicky about octane. I burned a good mid-grade and never had a problem with hesitation on starts. In both cases, I seemed to get slightly better mileage with premium, but that's probably the old "butt dyno" talking. Usually large gas stations off the heavily-traveled highways, preferably outside the city to take advantage of minimal taxes will offer the best prices. Use your loyalty cards - either from your bank or local merchants to get the best discounts
As Mike says, gasoline is gasoline, the difference is in the additive package - and the care with which it's pumped from the depot and delivered to your station's tanks. Whatever brand you prefer is really up to you. Most major brands now come with adequate additives for your area and normally take good care of their tanks and plumbing. Find a good clean station with at least moderately new tanks and fuel islands, particularly those with lots of traffic. If there's some kind of funk in the tanks, at least it's being spread over a large number of users - you won't get it ALL. Good tip about not fueling during or for several minutes after a fuel drop - let the dirt settle back to the bottom. Unless the tank or the plumbing is cracked, water condensate shouldn't be a problem in your fuel. The ethanol in today's fuels will adsorb a fair amount of water and pass it trough your engine harmlessly.
I've been the victim of filthy fuel myself and learned to carry spare fuel filters in case I get a shot of dirt or granulated rubber with my gas. It's pretty evident - as the fuel flow begins to be restricted, you find you are unable to maintain highway speed. A quick filter change will fix the problem, but finding the proper one at 3am on a deeply rural highway is no fun. Carry a spare. If you are blessed with one of those filters at the intake of the fuel pump in your tank, you may be in for a rather costly "fuel module" change that requires dropping the tank. It pays to be a little picky about the fuel you buy.
Here's a tip or two I got from a client who manufactures tanks and fuel plumbing for gas stations all over the US. The API requires tanks and fuel plumbing to be identified by color. A red cover over the tank inlet (usually found out of traffic somewhere on the driveway where the fuel trucks drop their load) indicates the "premium" tank inlet, blue for a mid-grade fuel, and white for regular. Often these caps or covers will have a white or black cross on them. Fuel dispensers (pumps to you and me) nowadays blend premium and regular to arrive at their mid-grade product (check to see if you find the fillers for those underground tanks, so you may not see a blue tank filler, confirming your mix is being performed at the pump. If you use a mid-grade fuel, try to buy your gas when the driveway traffic is at a minimum. Here's why:
Normally a mid-grade mix is fine, but if there are ten cars on the driveway, four taking premium, four mid-grade, and two, regular, you may find that the mid-grade blend delivered by your pump is a bit on the "weak" side, a bit less than a 50-50 mix you expect, as the pressure drop from those premium customers can have a considerable effect on your fuel delivery. This is common with old buried rubber hoses that aren't really efficient delivery piping for gasoline. Sadly, that's probably the case on 90% of all gas islands in the US. If you thought your gas was being blended by volume, it's not - it's pressure-dependent and you can be getting less than you're paying for. When the state certifies the pump, it's looking at total delivery at the nozzle, not how that mix is blended in the pump. There's no real control of that - except by the pump drawing the mid-grade fuel from a separate underground tank. It's perfectly legal, and most retailers don't want to mess with the extra tank and plumbing - but a few do. It's pretty much up to the individual operator.
BTW there are a couple other color codes that you may or may not find on the tank fill pipes during your inspection - diesel will be yellow, or yellow with a blue stripe (low sulfur diesel), biodiesel will be brown with a yellow rim, heating oil, green, and kerosene, gray. You should be able to see a color chart from the fill area, or at least posted on the wall inside the station office. A blue cap means your mid-grade is always going to be a proper blend, whatever the state of traffic on the driveway.
Last edited by Lil4X; 01-14-13 at 05:11 PM.
01-14-13, 05:44 PM
#10
Thanks. Some of them I learned myself; some passed on from others.
Chevron's well-known Techroline detergent additive is considered by a consortium of automakers (GM, BMW, Honda, Toyota, and others) to be the Tier-1 industry-standard for fuel-system protection. So, of course, is BG44K fuel-system cleaner (and other BG products)...but BG products are only sent to service-shops....they (usually) aren't avalable to the public at large.
Shell's V-Power detergent additive also has a good reputation. Shell is very popular here in the D.C. area, partly because Chevron stations are few and far between here, and partly because the Giant Supermarket chain here gives bonus-points for gas-discounts at local Shell stations.
Some of them I learned myself; some passed on from others. Chevron's well-known Techroline detergent additive is considered by a consortium of automakers (GM, BMW, Honda, Toyota, and others) to be the Tier-1 industry-standard for fuel-system protection. So, of course, is BG44K fuel-system cleaner (and other BG products)...but BG products are only sent to service-shops....they (usually) aren't avalable to the public at large.
Shell's V-Power detergent additive also has a good reputation. Shell is very popular here in the D.C. area, partly because Chevron stations are few and far between here, and partly because the Giant Supermarket chain here gives bonus-points for gas-discounts at local Shell stations.
Both my parent work for Chevron so granted I'm a little biased
01-14-13, 06:48 PM
#11
Lexus Fanatic
Thread Starter
My 2000 RX300 burned the "preferred" premium fuel, but ran fine most of the time on regular unleaded. The difference, I discovered, is common to many vehicles with sophisticated engine control systems - they may stumble a bit off idle with regular. The problem it seems is the fuel map stored in the ECU. Often it's "programmed" for premium, using a bit more spark advance to gain early power. Of course the knock sensor hears that first ping an dials back the advance, but sometimes in some cars (my first RX was one), it could cause a slight stumble off the line. For that reason, I used premium around town, and regular on long trips where hours at cruising speed out on the slab put few demands on the fuel map.
...it filled in some of the blanks that I left. You probably already know this, but the reason for that computer spark-retardation mapping in our higher-octane-preferred RX was not necesarily so you could run regular continuously (that's not what the engineers intended), but, for relatively short periods of time, to save the engine from excessive pinging from the really crap fuel that they sell in Mexico if you happen to run low on gas there and can't get decent American-grade stuff.
My 2004 RX330 was slightly different - while a bit unhappy with regular, a mid-grade fuel was perfectly fine. I guess it wasn't quite so finicky about octane. I burned a good mid-grade and never had a problem with hesitation on starts. In both cases, I seemed to get slightly better mileage with premium, but that's probably the old "butt dyno" talking.
As Mike says, gasoline is gasoline, the difference is in the additive package - and the care with which it's pumped from the depot and delivered to your station's tanks. Whatever brand you prefer is really up to you. Most major brands now come with adequate additives for your area and normally take good care of their tanks and plumbing.
Unless the tank or the plumbing is cracked, water condensate shouldn't be a problem in your fuel. The ethanol in today's fuels will absorb a fair amount of water and pass it trough your engine harmlessly.
I had forgotten about that.
Last edited by mmarshall; 01-14-13 at 06:57 PM.
01-15-13, 04:51 AM
#12
Great write up mmarshall! It is nice to see stuff that I have known for years and been doing written down and explained in great detail! I feel better knowing that I am not the only picky one out there one when it comes to gas.
01-15-13, 08:26 AM
#13
Lexus Fanatic
Thread Starter
Thanks.
A lot of this, of course, is not just "pickiness" but just common sense....like not gassing up on inclines wherever possible.
It is nice to see stuff that I have known for years and been doing written down and explained in great detail! I feel better knowing that I am not the only picky one out there one when it comes to gas.
01-15-13, 08:30 AM
#14
Lexus Fanatic
Thread Starter
My brother brought up another (apparantly) good tip....something that usually doesn't affect me, as I usually pay inside, not at the pump. He said, with a credit card, always remember to hit the "End Transaction" button if the pump has one. Apparantly, if this is not done (though he said it has never happened to him) someone behind you can piggyback off your transaction.
01-15-13, 08:41 AM
#15
Out of Warranty
Thanks Mike!
It surprised me to learn that Texaco or Exxon gas is seldom brand-specific. What you buy at your Shell station may well be a product refined by Exxon with the Shell's proprietary additives (usually a quart or two to 5,000 gallons of gas) poured into the delivery truck. Gasoline is what's called a "fungible commodity" - a product freely traded among nations . . . and your local gas pump. Unless your favorite station is an "O and O" (company owned and operated) facility, you can't be sure that the Shell you're buying actually came from our good friends in The Hague.
Independent station owners, whatever the sign out front says, tend to buy from the cheapest source available (within limits of course, you won't find Pemex here for good reason). Rack prices - the wholesale price of gas - vary from day to day and is played like the commodities market across some 225 cities and towns in the US. That's why those no-name tankers pull up to your station, they may be hauling Shell, Texaco, or Exxon today, as ordered by the station owner/manager . . . but they may be hauling something you never heard of - a generic gasoline that's holding a sale.
With even an average convenience store selling nearly 5,000 gallons of gas per day, a few cents per gallon saved at wholesale can make even a marginal station profitable. Currently, on average across the country the gross margin for gasoline is 16.3 cents/gallon, or 5.6 percent. That's entirely fair, considering the station has to pay utilities, handle cash, service the facility, and pay staff out of that margin. If the station owner can purchase perfectly good gasoline at wholesale for a couple of cents less by playing the market, that is pure profit, translating directly to his bottom line. 2¢ per gallon on a 5K gallon wholesale purchase is a quick $100/day boost in profits. For independent gas station owners, and often some franchise holders, it pays to play the market.
For consumers, if you want to be sure your engine runs clean and free of deposits, it's a good idea to run a jug of Techron or Seafoam through your tank every few months. At least that way you know you are getting the cleaning agents you are paying for.
It surprised me to learn that Texaco or Exxon gas is seldom brand-specific. What you buy at your Shell station may well be a product refined by Exxon with the Shell's proprietary additives (usually a quart or two to 5,000 gallons of gas) poured into the delivery truck. Gasoline is what's called a "fungible commodity" - a product freely traded among nations . . . and your local gas pump. Unless your favorite station is an "O and O" (company owned and operated) facility, you can't be sure that the Shell you're buying actually came from our good friends in The Hague.
Independent station owners, whatever the sign out front says, tend to buy from the cheapest source available (within limits of course, you won't find Pemex here for good reason). Rack prices - the wholesale price of gas - vary from day to day and is played like the commodities market across some 225 cities and towns in the US. That's why those no-name tankers pull up to your station, they may be hauling Shell, Texaco, or Exxon today, as ordered by the station owner/manager . . . but they may be hauling something you never heard of - a generic gasoline that's holding a sale.
With even an average convenience store selling nearly 5,000 gallons of gas per day, a few cents per gallon saved at wholesale can make even a marginal station profitable. Currently, on average across the country the gross margin for gasoline is 16.3 cents/gallon, or 5.6 percent. That's entirely fair, considering the station has to pay utilities, handle cash, service the facility, and pay staff out of that margin. If the station owner can purchase perfectly good gasoline at wholesale for a couple of cents less by playing the market, that is pure profit, translating directly to his bottom line. 2¢ per gallon on a 5K gallon wholesale purchase is a quick $100/day boost in profits. For independent gas station owners, and often some franchise holders, it pays to play the market.
For consumers, if you want to be sure your engine runs clean and free of deposits, it's a good idea to run a jug of Techron or Seafoam through your tank every few months. At least that way you know you are getting the cleaning agents you are paying for.
