Premium gas vs Regular unleaded

I drive a 2002 VW passat wagon. I have always put preium in it, but with gasoline prices where they are, is it okay to use regular unleaded? Will I harm my vehicle?

This has been heavily discussed lately (the search feature is your friend). You’ll find lots of good info on this subject.

Most agree if your owners manual states “premium required”, then you should continue using it. If the manual says “premium recommended or preferred”, then you should be able to use regular.

There are some who believe (some from experience) that you can use regular without any harm.

I’m in the “follow your owner’s manual” camp.

Specifically on the VW Passat and other high-compression engines, you can, but performance will suffer a little, as will fuel economy. You might save a little per gallon, but you might eat up your savings in fuel consumption. In essence, you won’t be saving much in the end. If regular is 10% less expensive, and you lose 2 MPG, you’ve not saved anything.

If it’s a 1.8T engine, you really should not use anything below 91 Octane. The V6 is somewhat more forgiving, but again, fuel economy will suffer on both.

I have an '03 Passat, so I know what I’m talking about. Check out - it’s a great forum for fellow Passat owners who love (and sometimes hate) their cars. This topic has been beat to death there, and my above opinions seem to be the consensus.

Have you realized the price differential is actually cheaper now than ever before??? Right now the price difference is about 5% more for premium. Back in the days of $2/gallon fuel it was a 10% increase for premium vs regular.

The price differential has remained the same ($0.20-$0.25/gallon) even back to the days of $1/gallon fuel that I can remember back in high school.

Repeat after me:

High Octane gas does not help an engine that does not need it. Octane is not a measure of quality or power.

Octane is a measure of how easy the gas starts to burn or how fast. High octane means it is hard to start burning. On the other end diesel is measured by certane and a high certane number means it is easier to start burning.

High octane gas may or may not have more additives like cleaners in it, but with today’s regulations any gas has enough for most engines.

   The owner's manual will say that it must have high octane or that it may use regular but should use high octane.  The parts the leave out are:

  * If it needs high octane, using regular can damage the engine.

  * If it should use high octane then it has a system to sense the low octane and to make adjustments to the car that will protect the engine.  However the adjustments will result in lower mileage (reducing or wiping out any economic advantage) and will reduce the power, defeating the reason most people buy cars that require high octane. 

  * Using high octane in a car that does not recommend it very very seldom causes damage but cost you more and offer no advantage.

Here’s a wacky idea. Open your glove compartment and read the answer straight from the people who designed your car.