Dear Tom and Ray,

I have been using high octane fuel but wondering if it is safe to replace it with regular fuel. I have a 2003, BMW, 325, with 97000 miles.

Thank you in advance.

Open that Owner’s Manual you should find in the glove box. It will say one of three things:

  • Premium Required
  • Premium Recommended
  • Use regular

If it says required, then you need to use it to protect the engine.

If it says recommended, then not using premium will reduce the power and the mileage your drive can give you. It is up to you, but since you will loose some mileage, you might end up paying more for less.

If it says regular, then use regular as there is no advantage to using high octane (the oil companies loved the word “Premium” because it got a lot of people to use it that did not need it.

It might even state what is required on the gas cap…

As far as I know, the high performance engine in all BMW cars (except the diesels) require premium fuel.

The owner’s manual will tell you what fuel is required.

Millions of BMW’s run fine on Regular. It’s not a safety issue…Try a tank and see what happens. If you hear the engine start to “ping” when you accelerate, then you better stick with premium. If you can detect no complaint from the engine, no damage is being done and you can use regular…