I’m not sure what octane fuel I need to put into my car. I’ve not found an answer in the owner’s manual or on the Volvo website. I’ve been using premium for the entire 110K miles so far. Can I save some money with mid-grade without damaging anything? If so, are there other downsides?
Thank you for your help.
Every owners manual I’ve ever seen lists the engines octane requirement…Take a second look, it’s gotta be in there somewhere…
This car should be turbocharged so you’re likely going to be stuck with using premium.
The downside to lower octane gasoline is that the engine may be destroyed if there is any severe or chronic pinging going on.
Www.fueleconomy.gov says it runs premium. If yours has a turbo, I guaranty it runs premium. Every owners manual I’ve seen includes octane requirements. Yours should, too.
Turbo = premium for me.
Your car has a turbocharged engine, premium fuel required. Yes, required. You could switch to mid-grade but you wouldn’t be saving any money, really, when you think about it.
It appears you drive about 11,000 miles per year, 212 miles per week. Assuming you only get 15 miles per gallon (surely you get more), and the price spread between mid-grade and premium is 10 cents/gallon, and you buy 14 gallons per week, you will save $1.40 every week. So your sacrificing performance and risking engine wear and possible damage for less than the cost of a cup of coffee per month. How does that make any sense?
Cars are pretty important to most people. If saving $6 each month is an important monetary concern I hope you’ve turned off your cable, land-line telephone, and internet service already.
It is certainly worth asking, and I agree with everyone else: continue using premium gasoline. BTW, the gas cap may have gas grade commendations on it,or there might be a sticker on the inside of the gas filler for.
Although a lot of information tends to get buried in the text of an Owner’s Manual, almost all manufacturers list the really vital information on the inside of the back cover, where it can be easily found. That really vital information includes things like the octane that is required, as well as the grade and viscosity of the motor oil that is needed. I would be very surprised if the OP’s Owner’s Manual did not list the octane requirement on the inside back cover.
All of that being said, if it is a turbo-charged engine, it almost surely calls for high-octane (premium) gas.
Very interesting how so many of you assume turbo=premium. C’mon guys, this ain’t the 1980s! While a brand like Volvo may indeed specify premium for its turbo motors, there are many modern (I consider 2004 modern) turbos that do not.
@NYBo
I usually agree with some who dosen’t agree with everyone else in general. 
But, I f OP has a working Volvo with this many miles and is just getting around to asking what type of gas to use, I wouldn’t change. That’s a lot of miles on a Volvo without problems using premium. The maker knows for sure.
MichiganDriver, first, as noted the info is in your manual someplace, and very well might be printed right on your gas cap of filler door. There will be language in the manual that gives a certain octane level as either “recommended” and/or “required.” If it says required then you don’t mess with it. If it says recommended - well, then you can sort of do what you want, but you should understand what it means.
The octane ratings get labeled “regular” and “mid-grade” and “premium” (or similar) - but this doesn’t have even the slightest thing to do with gasoline “quality.” All an octane rating represents is the gasoline’s resistance to combustion. The lower the octane, the easier it is for the air/fuel mix in your cylinder to explode. Higher octane gas doesn’t combust as easily. (This is not a difference you’d notice with a match).
For any engine to run at its optimum, and thus over the long haul to be healthiest and most efficient, the air/fuel mix is supposed to blow at an incredibly precise moment in the engine’s cycle. This is supposed to happen from incredibly precise timing of the spark going to the spark plugs.
The problem is that the spark plug is not the only thing that can make the air/fuel mix explode. One thing that can make it explode, even in the absence of spark from the plug, is just compression. What folks are saying is that you engine is probably a turbo and probably with relatively high compression. So if you use lower octane fuel your air/fuel mix might frequently be combusting out of time - i.e. when it’s not supposed to. This is what engine “knock” refers to (although that specific term gets used imprecisely. Another common name for this kind of knock is “ping”).
Knocking is very bad for an engine. These days engines have knock sensors. They “listen” and tell the computer and the computer adjusts to minimize knocking. So if you do run a lower octane gas and it creates knock problems, you might not notice. Many people do though - they can tell that their engine has reduced power and worse fuel economy. In the end the knock sensors will probably prevent engine damage, but your car wont’ run at its best or at optimum efficiency.
So the whole thing can be something of a gray area. Can you step down without damaging anything? Probably. Can you do it without any ill-effects - mmmmm - maybe/maybe not. But if you actually do the math on the price difference (see asemaster’s post) you’ll probably find out the impact on your wallet is less than it seems.
Page 84 of the owners manual states that 91 octane is preferred, but it will run on 87 or higher octane
http://new.volvocars.com/ownersdocs/2004/2004_XC70/04xc70_06a.htm#pg84
MichiganDriver:
When I look up your owner’s manual (http://new.volvocars.com/ownersdocs/2004/2004_XC70/04xc70_06a.htm#pg84), I see:
Fuel requirements Octane rating: Volvo engines are designed for optimum performance on unleaded premium gasoline with an octane rating AKI of 91, or above. AKI (ANTI KNOCK INDEX) is an average of the Research Octane Number, RON, and the Motor Octane Number, MON. (RON + MON/2). The minimum octane requirement is AKI 87 (RON 91).
Does your car have a turbo? Because they make no distinction for a turbo, which surprised me.
The XC70 only had one engine, a turbo 5. While it might run on regular without damage, I bet it’ll put out more power, and probably get enough better mpgs to justify the price, on premium.
Volvos are still considered as European cars.
In general at the petrol stations you will find 95, 97 and 99 octane fuel. So even the lowest grade gas has a higher octane rating than The US premium. Now to get around this EU cars have modifications for the US market, mainly computer control of the engines. I would still use premium even the manual okays lower grade.
If anything happens to your car, you are going to pay for a repair, not the person who wrote the manual…
Different octane scale.
Different measurement but there is still 5-8 octane difference.
Nope. European premium is 98, US premium is 93, all due to the different ranking system:
“Because of the 8 to 10 point difference noted above, the octane rating shown in Canada and the United States is 4 to 5 points lower than the rating shown elsewhere in the world for the same fuel.”
Fuel requirements
Octane rating: Volvo engines are designed for optimum performance on unleaded premium gasoline with an octane rating AKI of 91, or above. AKI (ANTI KNOCK INDEX) is an average of the Research Octane Number, RON, and the Motor Octane Number, MON. (RON + MON/2). The minimum octane requirement is AKI 87 (RON 91).
Found at http://new.volvocars.com/ownersdocs/2004/2004_XC70/04xc70_06a.htm#pg84
with a quick google search.
Wow! Asking my question on cartalk.com really worked! I am grateful and impressed. I learned a whole lot about my car, octane, engines in general, car performance, and calculating savings on fuel. Oh, yes, and about my owner’s manual. MANY THANKS to all for taking the time to respond. I’m definitely sticking with premium, but now withou a worry that I might be wasting money out of ignorance.