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Regular Gas Last Resort

Last night I got stuck in a situation where I was at a gas station in the middle of nowhere with a car that requires premium fuel. Since I was not sure if I’d make it to the next stop I opted to refuel with the regular fuel. So I put in 5 gallons and got back on the highway.

When I got to a station with premium I filled the tank up all the way. Did I just do damage to my car?

MB E320 1999 Automatic 300 miles

As long as you drove “conservatively”, it is very unlikely that you did any permanent damage.

You should be fine, 5 gallons of regular + 10 or more gallons of premium, no problem. And the E320 is not turbocharged. I wouldn’t give it a second thought.

You did no damage whatsoever. You can sleep soundly.

@threephi you’re fine. The engine control module adjusted the ignition timing to compensate for the 87 octane fuel.

You did perfect.

With only 300 miles I am surprised you needed fuel :).