Car Care FAQs
To help you learn more about gasoline, we have assembled a collection of the most
frequently asked questions, all answered by our Fuel Experts. Browse by topic to find the answers.
Q. All the major oil companies say that their gasoline is great.
Why should I buy Chevron gasoline?
A. All Chevron-branded gasolines contain the unique Techron® additive. Techron contains
a polyether amine (PEA)-based chemistry designed to help keep vital engine parts clean
and remove deposits left by lower quality gasolines, while minimizing any contribution
to harmful combustion chamber deposits. Chevron with Techron was also the first
gasoline to be designated as a TOP TIER Detergent Gasoline by BMW, General Motors,
Honda and Toyota in the US and Canada.
Q. Why should I buy Chevron gasoline over lower quality gasolines?
A. Lower quality gasolines can leave harmful deposits in your car's engine. As these
deposits accumulate over time, your car may begin to hesitate and stumble during
acceleration, knock or lose power. Chevron with Techron® is unbeatable at helping clean
up your engine, which can reduce emissions, restore lost power and performance,
and helping keep your engine clean. There's no better gasoline for you to help protect your
engine's performance than Chevron with Techron.
Q. I already buy premium gasoline. Why should I buy Chevron Supreme®
instead of my current brand?
A. Deposits on fuel injectors, intake valves and combustion chambers
can cause your car to produce higher emissions, which contribute to air pollution.
Chevron Supreme with Techron® is unbeatable at cleaning up the intake systems and
avoiding these deposits, giving you reduced emissions compared to lower quality
premium gasolines. All Chevron branded gasolines contain the unique Techron additive.
Techron contains a polyether amine (PEA)-based chemistry, designed to help clean up intake
system deposits while minimizing any contribution to harmful combustion chamber
deposits that may increase emissions or lead to deposit-related engine knock or
Q. What is Techron®?
A. Techron is a fuel additive that acts as a detergent to help keep your engine
clean. Techron uses polyether amines (PEA) to help fight deposits in an engine's
intake system and minimize contribution to harmful combustion chamber deposits.
Over 30 years ago, after discovering that PEAs made effective deposit control additives,
Chevron patented them and has been reformulating and improving Techron ever since.
Q. What makes Chevron with Techron® special?
A. Many other gasolines use a detergent additive that's based on polybutene amine
(PBA) chemistry. PBA-based additives do an adequate job of controlling intake system
deposits-but only if the dosage in the fuel is high enough to do the job. In recent
years, the concentration of PBA in many gasolines has fallen so low that the gasolines
do not keep intake systems clean. And if a gasoline uses a concentration of PBA-based
additive that's high enough to keep the intake system clean, the additive itself
can contribute materially to combustion chamber deposits. Excessive combustion chamber
deposits can cause an engine to need a higher octane gasoline to avoid knock or
loss in performance. These excessive deposits can also cause higher tailpipe emissions.
In contrast, Chevron's unique deposit control additive, Techron, provides unbeatable
intake system deposit control, while simultaneously minimizing any contribution
to harmful combustion chamber deposits.
Q. I was told that Chevron has the Techron® additive in all grades
of gasoline? Is this true? I thought it was only in the Supreme grades.
A. It's true. All grades of Chevron gasoline contain a highly effective amount of
Techron, so no matter which grade your car takes, it's getting the quality and unbeatable
cleaning power of Chevron with Techron.
Q. Do I need to add a bottle of deposit control additive such
as Techron® Concentrate Plus to the gasoline in my fuel tank?
A. If you regularly use a high-quality gasoline such as Chevron, you probably don't
need Techron Concentrate Plus. However, if you have an engine that is sensitive
to deposit formation, or if your vehicle is regularly used under severe conditions,
you may also benefit from using Techron Concentrate Plus.
Q. What is the difference between Chevron with Techron® at the
pump and Techron Concentrate Plus in the bottle?
A. The principal difference is additive concentration and rate of deposit clean-up.
Chevron gasolines with Techron over multiple fill-ups will help clean deposits on
intake valves and minimize harmful combustion chambers deposits. When added to a
full tank of gasoline, a bottle of Techron Concentrate Plus results in an additive
concentration roughly 10 times stronger. This mega-dose of Techron provides a much
quicker clean up of intake valve deposits left by lower quality gasolines. In addition,
the high concentration of Techron reduces combustion chamber deposits, which can
help eliminate deposit-related engine knock or power loss.
Q. Is Techron® just a more diluted version of Techron Concentrate
A. No. While both use a polyether amine-based chemistry, each is optimized for its
particular application. Chevron with Techron helps clean engine deposits left by
low quality gasolines and helps keep engines clean through regular use, while Techron
Concentrate Plus provides a quicker clean-up of deposits left by lower-quality gasoline
through a higher additive dose optimized for fast cleanup.
Q. My car is knocking and pinging. What is causing this? Can
Techron Concentrate Plus help?
A. Knocking and pinging is generally caused by improper combustion in your engine,
called “auto-ignition.” If the gasoline-air mixture auto-ignites somewhere in the
cylinder (other than at the spark plug) just after spark ignition, the auto-ignition
combustion wave can interact with the spark-initiated combustion wave, causing the
vibration we hear as knock or ping. Increasing engine load, temperature, compression,
spark-advance, air-fuel ratio and combustion chamber deposits all increase the tendency
for an engine to knock. Using higher octane gasoline reduces an engine's tendency
to knock. If excessive combustion chamber deposits are contributing to the knocking
problem, you may benefit from adding a bottle of Techron Concentrate Plus to your
next tank of gasoline.
Q. What oxygenates does Chevron use for oxygenated and reformulated
A. Chevron only uses ethanol in its oxygenated gasolines.
Q. Will using oxygenated gasoline reduce my gas mileage?
A. Oxygenated gasoline reduces fuel economy an average of 2 to 3 percent because
oxygenated gasoline contains less energy than non-oxygenated gasoline. Many other
factors can impact mileage far more than oxygenated gasoline. Things like:
- How well your car is maintained
- How fast you drive
- Traffic congestion
- Rain and snow, cold weather, and tire pressure
Q. Can I use oxygenated gasoline in my lawnmower? How about my
A. Our survey of the manufacturers of engines for non-automotive uses — boats,
garden tools, chain saws and snowmobiles — indicates that oxygenated gasoline
will perform satisfactorily in most later-model engines. However, some manufacturers
expressed concerns about its use in older engines. The owner's manual is the most
authoritative source of information about the fuel requirements of your equipment.
If your equipment is older and the manual does not mention oxygenated gasoline,
consult an authorized dealer.
Q. What is Ethanol?
A. Ethanol is ethyl alcohol or grain alcohol, mainly produced in the Midwestern United States from corn stock and in more limited quantities in Canada from wheat. It can be used as a biofuel alternative to gasoline. British Columbia and Canada require that gasolines contain an average of 5 % renewable fuel content. To meet BC's Renewable Fuel Standard, Chevron gasolines may contain up to 10% ethanol.
Q. It seems like the dispensers at every retail station I go to has a "contains ethanol" decal on it. Why is this?
A. BC's Renewable Fuel Standard came into effect on January 1, 2010. To meet this fuel mandate, Chevron gasolines in British Columbia may contain up to 10% ethanol.
Q. What is octane?
A. Octane, or Octane number, reflects a gasoline's antiknock quality. It's a measure
of the ability of gasoline to resist knocking when it is burned in an engine. Laboratory
testing that determines a gasoline's octane number involves burning the fuel in
a single-cylinder engine under different conditions to yield a Research octane number
(RON) and a Motor octane number (MON).
Q. My car owner's manual says that I can use regular unleaded
gasoline. Is it true that a car engine's octane requirements can increase over time?
A. Yes, and Chevron Supreme and Plus gasolines have high octane that can help maximize
performance in cars with increased octane number requirements. Over time, deposits
can accumulate in your car's combustion chambers. These deposits can cause knocking
and pinging, or reduced performance, particularly if your car has driven over 24,000 kilometers. A higher octane number gasoline can help you reduce or eliminate these problems
by improving your engine's combustion process. While some of these engines may be
satisfied by the octane offered by our Plus grade, others may require the even higher
octane of Chevron Supreme. So if combustion chamber deposit build-up is affecting
your car, Chevron Plus and Supreme with Techron® can help.
Q. Can knocking harm my engine?
A. Occasional light knocking won't harm an engine. Heavy or prolonged knocking can
result in a loss of power, overheating of parts in the cylinder and engine damage.
Techron® Concentrate Plus has been proven to help deposit clean-up for fuel injectors,
ports and intake valves and combustion chambers. It actually helps restore performance
lost due to deposit build-up.
Q. How can I stop my vehicle from knocking?
A. Have a mechanic determine whether your engine is in tune and the emissions control
system is functioning properly. If it is, then there are two courses of action.
- Use a gasoline with a higher antiknock index (AKI)
- Treat the gasoline with a bottle of Techron® Concentrate Plus. If there are combustion
chamber deposits in the engine, the treatment will reduce them, which, in turn,
may lower the octane number requirement of the engine. This may decrease the engine's
tendency to knock until these deposits reform.
Q. How much octane do you need?
A. If you have an older car or a high performance car, you may need a higher octane
gasoline to help prevent engine knocking.
Your driving conditions can increase your car's octane requirements. For example:
- Do you make a lot of short trips?
- Do you drive in high temperatures?
- Do you carry or pull heavy loads?
- Do you drive in a low altitude area?
If you answered yes to any of the above, your vehicle may perform better with a
higher grade of Chevron with Techron®. If your engine is knocking or losing power
on a lower octane fuel, in most cases, switching to a higher octane fuel can help.
Q. What octane gasoline should I use in my vehicle?
A. For starters, use a gasoline with the octane number (AKI) recommended by your
owner's manual. Using gasoline with an antiknock rating higher than that required
to prevent knock will not improve a vehicle's performance, including its power,
unless the vehicle is equipped with a knock sensor and the car's computer is controlling
the engine to reduce or eliminate knock on the lower octane grade fuels. Many late
model high-performance engines fall into this category.
There are two reasons why your vehicle might knock on a gasoline with the AKI recommended
by the owner's manual:
- The engine is at the upper end of the octane number requirement range.
- Combustion chamber deposits in your engine are higher than usual.
Q. What will happen if I use the wrong octane gasoline in my
A. Using a gasoline with an AKI lower than required by your vehicle can cause the
engine to knock or lose power. If the engine is equipped with a knock sensor and
the car's computer is controlling the engine to reduce or eliminate knock, using
a gasoline with an AKI lower than that required by your vehicle will decrease the
vehicle's power and acceleration. Using a gasoline with an AKI higher than that
required by your vehicle will not improve its operation.
Q. What determines my car's octane requirements?
A. Your car's octane requirements are mainly determined by its basic design. In
addition, variations in engines due to manufacturing tolerances can cause cars of
the same model to require a different octane of several numbers. Also, as a new
car is driven, its octane requirement can increase because of the buildup of combustion
chamber deposits. This continues until a stable level is reached, typically after
about 24,000 kilometers. The stabilized octane requirement may be 3-6 numbers higher
than when the car was new. Premium or mid-grade fuel may be advisable to prevent
knock or loss of power.
Other factors also influence your car's knocking characteristics:
- Temperature - Generally, the hotter the ambient air and engine coolant,
the greater the octane requirement.
- Altitude - The higher the altitude above sea level, the lower the octane
requirement. However, modern computer-controlled engines adjust spark timing and
air-fuel ratio to compensate for altitude changes, and thus the effect of altitude
on octane requirement is smaller in these vehicles.
- Humidity - The drier the air, the greater the octane requirement. The recommendations
that vehicle manufacturers give are for normal- to low-humidity levels.
- Engine spark timing - Octane requirements increase as spark timing is advanced.
Both the basic setting of the spark timing and the operation of the automatic spark
advance mechanisms are important in controlling knock. In some computer controlled
engines, the spark timing can only be changed by replacing modules in the computer.
If they are equipped with knock sensors, these computer controlled engines have
the ability to retard the ignition temporarily when a sensor detects knock. This
temporarily reduces the octane requirement and may also temporarily reduce vehicle
- Method of driving - Rapid acceleration and heavy loading, such as pulling
a trailer or climbing a hill, may result in a greater octane requirement. Stop-and-go
driving and excessive idling can increase octane requirements by causing the buildup
of combustion chamber deposits.
- Malfunctions of emission control systems - An improperly functioning emissions
control system can affect the octane requirement by changing the air-fuel mixture
or by not providing dilution gases through the exhaust gas recirculation (EGR) system.
If a malfunction occurs, your vehicle should be taken to a qualified vehicle service
mechanic. Some problems are indicated by warning lights on the driver's instrument
Q. What can I do to get better fuel economy?
A. Good fuel economy is a combination of good vehicle maintenance and sensible driving.
Maintenance factors which contribute to good fuel economy are:
- A properly tuned engine
- A clean air filter
- Aligned and balanced front wheels
- Tires with the correct air pressure
Mistuned engines also result in higher emissions. The onboard diagnostic system
in a modern car will alert you to an engine problem.
Sensible driving involves:
- Smooth, steady acceleration rather than jackrabbit starts
- Driving at moderate rather than high speeds on the highway
- Not carrying a heavy load using a luggage rack, or towing a trailer unnecessarily
- Not using the air conditioner or defroster excessively
- Not idling the engine when it could be turned off
Some factors which reduce fuel economy are beyond your control: water, slush, or
snow on the road, head winds, driving up hill, and driving in stop-and-go traffic.
Q. What are the guidelines for storing gasoline?
A. Chevron gasoline can be stored for a year without deterioration when the storage
conditions are good — a tightly closed container, moderate temperatures, and
out of direct sunlight.
Chevron recommends that gasoline not be stored unnecessarily. A supply that won't
be needed for several months should be used and replenished when the need reoccurs.
Q. What are the guidelines for filling a gasoline container?
A. Below are the guidelines that are recommended for filling a gasoline container:
- Use only an approved portable container (1 to 5 gallons or 3 to 19 liters, metal or ULC (Underwriters Laboratories of Canada)or CSA (Canadian Standards Association) approved container. Never
store gasoline in glass or unapproved containers.
- When filling container, follow same rules as when fueling car: turn off engine;
extinguish smoking materials, leave electronic devices in the vehicle.
- Place the portable fuel container on the ground during filling, and keep the metal
nozzle spout in contact with the container to prevent build up and discharge of
static electricity. Never fill a container in the bed of a pickup, in the back of
a station wagon, or in the trunk of a car.
- Keep container five feet away from cars to prevent ignition of fumes by hot engines
or mufflers. Ask others, particularly children, to stand back during filling.
- Manually control the nozzle valve throughout the filling process. Fill a portable
container slowly to decrease the chance of static electricity buildup and minimize
spilling or splattering.
- Back off on the trigger to slow fuel flow as the container becomes full. Fill container
no more than 95 percent full to allow for expansion. When filling
is complete, tightly cap container. Wipe off any gasoline that spilled on the outside
of the container. Ask the station attendant to properly dispose of the material
used to wipe off the gasoline.
Q. Can static electricity really be enough to ignite gasoline?
A. Yes, but static electricity-related incidents at retail gasoline outlets can
be avoided. In the unlikely event a fire occurs when refueling, leave the nozzle
in the fill pipe and back away from the vehicle. Notify the station attendant immediately
so that all dispensing devices and pumps can be shut off with emergency controls.
Use the emergency shutdown button to shut off the pump.
Safety tips to avoid static electricity buildup:
- Upon exiting vehicle and before handling the nozzle or fuel door, always touch a
metal part of the vehicle such as the door or hood.
- To avoid a build-up of static electricity, do not get back into your vehicle during
- If you cannot avoid getting back into the vehicle, upon exiting always touch a metal
part of the vehicle away from the fill point before handling the nozzle.
To minimize the danger from fire while filling a portable container with gasoline:
- Turn off your vehicle's engine.
- Extinguish smoking materials (cigarettes, pipes, etc.).
- Remove the container from the vehicle and place it on the ground a safe distance
from the vehicle.
- Keep the nozzle in contact with the container at the inlet during fuel transfer.