Vehicle MD - A Driver's Guide to Maintaining a Healthy Car

Ethanol

To the Doctor:
Could you please clarify all the things I have heard about putting a stabilizer in your car's gas tank to offset the harmful effects of ethanol in the gasoline? We do put a stabilizer in our gas trimmer, and our tractor mower, according to our manuals, but have never been able to get a consistent answer regarding adding to car engines.
The Doc Says:
While a fuel stabilizer has its benefits for any vehicle, including those not specifically built as a flex-fuel vehicle (or one capable of using anything from pure gasoline all the way up to E85, which is 85 percent ethanol), if any of the following apply then the benefits you stand to gain from use of a fuel stabilizer are much increased:

• Your car is older (generally built prior to the year 2000)
• You do not drive frequently and/or plan to store the car/fuel for an extended
period of time (typically 90 days or more)
• You live in an extremely humid climate

Under those conditions, use of a fuel stabilizer is very much warranted. Older cars were not manufactured with components able to withstand the caustic nature of ethanol. Plus, since ethanol attracts water, it typically doesn't have a very long "shelf life," and if you store your car or fuel for extended periods, a fuel stabilizer will help prevent the fuel from undergoing phase separation, where the water in the ethanol/gasoline mixture suddenly drops out of suspension, which can clog filters, fuel lines, injectors, etc. The same goes if you live in very humid climates.

A Second Opinion:

There are a few reasons for adding a stabilizer to ethanol-blended fuels: 1) ethanol's ability to absorb moisture 2) ethanol's corrosiveness 3) lack of lubrication 4) ethanol-blended fuels break down in a short period of time (to form gum and varnish).

Stabilizers need to address these concerns to really protect your vehicles fuel system and stabilize fuel.

Adding a fuel stabilizer will prevent phase separation of the ethanol, moisture and gasoline. Because ethanol is a dry fuel that has no lubrication and can corrode metal parts and decay rubber in fuel systems, a fuel stabilizer adds lubrication for protection.

Ethanol-blended fuel can start to break down into gum and varnish within 30 to 45 days. A fuel stabilizer keeps the fuel liquid and viable, helping prevent it from turning into gum and varnish.

Jim Davis
Technical Service Director, Sea Foam Sales Co.
ASE Certified Automotive Technician

The advice described above is for informational purposes only. It cannot and should not be used in lieu of an actual, physical inspection and diagnosis by a trained mechanic or automotive technician. The opinions and advice offered herein are not intended to diagnose automotive problems or component failures; they are simply intended to provide information on what could be transpiring. VehicleMD accepts no liability resulting from actions taken as a result of this advice.