I stopped at a gas station that I don’t normally go to and got a few bucks worth of gas the other morning.
As I was pumping the gas, I was looking at the pump and the labels. Turns out that the gas I had chosen was labeled “Regular Leaded.” My car has the standard notice on the dashboard, “Unleaded Fuel Only” and I got to wondering. I hadn’t known leaded gas to be available anywhere for the last dozen years or so.
A) Is leaded gasoline still available for purchase in the US?
B) If it was indeed leaded gasoline, will the 2.044 gallons that I put in my car going to hurt it?
A) Yes, but only for airplane fuel. Tetra ethyl lead is an antiknock (octane booster) additive. Today’s automotive gasoline and octane boosting additives do not contain lead.
B) It wasn’t - my WAG is that it was probably an older pump which was never upgraded. But, even if it was, a couple gallons probably aren’t going to do any permanent damage. Extended use would eventually clog the catalytic converter.
I was a really young kid when I last saw leaded gasoline, but I don’t think there was any difference in nozzle size. IIRC, you just had to read the label on the pump.
I’m pretty sure there was. The problem wasn’t putting leaded in an unleaded car accidentally, since the leaded nozzle was larger; it was putting unleaded in a leaded car, which caused valve seat erosion problems, IIRC.
Yes, back when unleaded gas become available the fill nozzle was smaller than the leaded gas nozzle.
In 1976 I bought a new Ford, it was designed for unleaded gas only.
Unleaded gas back then was much higher than leaded gas. So I knocked out the small nozzle reducer in the gas tank fill tube so I could burn the lower priced leaded gas. I put about 90,000 miles on that car before trading it for a new one. Never a problem with the car, I’m sure the catalytic converter had ceased to function.
By the time I bought my next new car the price for unleaded and leaded was the same so I started burning unleaded.
I haven’t seem any leaded gas for sale in several years.
Having owned a couple of old cars that were designed for leaded gasoline, I can testify that the filler hole is really big compared to the unleaded fuel nozzle. I also can remember pumping gas as a child (back in the 70s, they didn’t freak out about that sort of thing) and the leaded nozzle was much bigger and wouldn’t fit into a car that took unleaded. They even sold an “emergency” adapter so that you could put leaded gas into an unleaded car in an “emergency” situation.
Nowadays, if you have an old car that is designed for leaded gas, you have no choice but to put unleaded in, and they run fine, but it’s a good idea to put the lead additive in every few tanks, otherwise bad things will eventually happen…perhaps the valve seat erosion, but I don’t remember exactly what. Haven’t had a car that old in about 10 years.
OK, here is the deal.
Leaded gas for automotive use has not been sold in the US for many years (last leaded gas was sometime in the 80’s IIRC)
Leaded gas has a much larger nozzle than unleaded pumps, this was done to prevent the introduction of leaded gas into an unleaded car.
Unleaded gas still uses the smaller nozzle. Cars still have a restrictor to prevent the introduction of fuel from the larger leaded nozzles.
Leaded gas won’t “hurt” an unleaded engine unless you consider the fact that the lead will foul the oxygen sensors and destroy the usefulness of the catalytic converter in a fairly short order. Would 2 gallons do this? Don’t know, but with the cost of new oxygen sensors and converters, this is not an experiment that I am planning to undertake.
And last but not least, Catalytic converters don’t wear out. A catalyst is not used up in a chemical reaction. I have seen many cars with more than 200,00 miles that are still using as original converters, and will still pass California emission tests. My daughter’s car has 140,000 miles and passed its last smog test with almost zeros (0.01PPM CO, 10 PPM HC, 10 PPM NOX). Mis-fueling (when leaded gas was available), misfire, and other issues with the engine can however kill them in short order.
Bottom line, unless you bought gas at an airport, it is almost 100% certain that you got unleaded gas.
I have a kit car that is basically a very much modified 1960 VW beetle, which of course was designed to run on leaded gas. From what I’ve been able to figure out, if you don’t drive the car much, unleaded gasoline isn’t going to do much damage, so it really doesn’t matter much for old collector type cars like what I have. If you do drive it a lot, you’ve got a choice of either using a lead additive or replacing the valves with stronger ones.
Leaded gas is most certainly being sold for cars - race cars. I know lots of people that run leaded gas in their car while at the track. They make it thru about 30 gallons before the O2 sensor starts to get lazy. I keep the blower pressure low enough for the unleaded stuff to work
AFAIK, not exclusively because of environmental problems in the sense of birds and flowers, but pollution of the human environment - cars and humans share a lot of space and humans (particularly the small kind) are somewhat susceptible to problems associated with lead compounds.
Leaded gasoline contains tetraethyllead (technically, tetraethyl lead(IV)), (CH[sub]3[/sub]CH[sub]2[/sub])[sub]4[/sub]Pb. It would be highly toxic, since the ethyl groups would help it dissolve in organic material. The lead itself doesn’t contribute to the substance’s antiknock properties. In the engine, the four ethyl groups in tetraethyllead break off, forming ethyl radicals, CH[sub]3[/sub]CH[sub]2[/sub][sup].[/sup]. The ethyl radicals aid in the combustion of the fuel by promoting its breaking down into smaller components. When fuels burn, they break apart into radicals – for example, six-carbon hexane might break into a four-carbon and a two-carbon radical. The radicals combine with oxygen much more easily than the fuels themselves; eventually, you get one-carbon radicals, and these combine with oxygen to form carbon dioxide. (Or a multiple-carbon radical could break apart – forming carbon dioxide and releasing energy is the point.)
The ethyl radicals from tetraethyllead help to initiate this process. This makes components of the fuel that do not easily break down (straight-chain fuels, which normally cause knocking in a gasoline engine) to break down more easily. Highly branched fuels break down more readily than straight-chain fuels; they have higher octane ratings (i.e. better anti-knock properties). Tetraethyllead makes straight-chain components break apart more like branched-chain ones; therefore, it increases the fuel’s octane rating. The lead, as I mentioned, does nothing to contribute. I’m not entirely sure how unleaded fuels achieve the same octane ratings; additives such as MTBE probably are a part of it, and refineries might produce fuels with more branched-chain components as well.
I don’t know if it’s still being sold today, but I did encounter leaded gas as recently as 1995 on the Navajo Reservation in Arizona. I pulled into a gas station and started to select the pump marked “regular,” which nowadays means basic unleaded gas, but back in the “old days” of both leaded and unleaded gas meant leaded. At this station, the latter convention was still in effect. I got as far as pulling out the nozzle and moving towards my car when I noticed the sign indicating it was leaded gas. I thought I had barely missed destroying my car’s fuel system, but later I learned that the nozzle would not have fit in my tank, a design move intended to prevent that from happening.
I was surprised that leaded gas was still for sale-- I hadn’t seen any sold since early childhood (mid-late seventies.) On subsequent drives out to Arizona I have not noticed leaded gas for sale, but I didn’t go out of my way to look for it, either.