"Premium fuel" recommended--bogus or for real?

kerldc1 · Post by **kerldc1** » 24 Sep 2009, 16:54

New owner of low mileage 2006 S60 2.5T. Dealer (and owner's manual) recommend premium fuel (R+M/2) of 89-91. I'm confused, and Car Talk seems to suggest against hard-and-fast rule Yes or No. How about every 3rd tankful put in RON=91 and the other times RON= <91 ? Damage will occur? What's your advice, as this car has to last us for lots of miles!

Post by **JDS60R** » 24 Sep 2009, 23:14

Follow your owner manual to be safe. A recent thread showed a rash of burnt valves from regular gas. I have no data to support this its just another thread.

Technically speaking at some level at octane and load you will begin to detonate. If the knock sensor can not back the timing off enough to eliminate the knocking then you will get detonation and it will eat something metal (valve, piston, cylinder wall etc)

I would use what Volvo suggests and not worry about it. It is only a few dollars a week between grades of gas and that amount of money can be saved elsewhere. (i.e - doing preventative maintanance yourself will save far morer than you will spend on the reccomended grade of gas - or using a discount card or credit card that saves you 5% or more by using one retailer of gas )

Post by **OEMVolvoParts** » 25 Sep 2009, 08:42

First of all congratulations on just opening your owners manual, let alone actually reading it! You are in the minority on that one.

Im assuming the reason you would want to use the lower grade of gas is to save a couple bucks. Well your car will reward you with reduced performance and lower your gas mileage, to the point that you aren't really saving any money. I would just give her the top shelf stuff, and keep her happy.

dvc100 · Post by **dvc100** » 01 Oct 2009, 21:11

There was a huge and both scientific and emotional discussion on this in my Acura forum that ran for many pages. The bottom line was use what's recommended. You probably won't notice the difference short term if you don't need max power all the time when you use regular but you don't save much money. You do get better performance with hi-test. And if you want to keep the car for a long time, use the good stuff.