posted by
someone claiming to be Hugh
on
Wed Dec 23 15:05 CST 2020 [ RELATED]
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Hello All,
I have a 1999 V70 AWD XC wagon, with 222,000 miles. The owner's manual recommends 91 octane gasoline. I purchased this car used with 12,0000 miles in 1999. From the start I ran it on 87 grade, because long ago at an Volvo Open House, at the company's then headquarters in Rockleigh, NJ, a Volvo engineer said you could run the car on 87 without effect. At 163,000 a valve failed. At 193,000 miles, another valve failed. All the valves were replaced each time a valve failed, so of course this was expensive. Now at 220,000 miles, it definitely appears the catalytic converter is failing. It was replaced 8 years ago when it was damaged due to a collision and not because of internal failure.
Today I had conversation with a very knowledgeable person at iPd, Inc. who has advised me, that I should always run run the car on 91 octane. That the problems I have described above are related to running the car on 87 and not 91 octane.
My question to my fellow Volvo Owners is: What is your opinion or practice in terms of the grade of gasoline that you use for your Cross Country?
I will welcome your comments and advice. Thank you in advance to all who reply.
Hugh
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So, one set of valves only lasted you 30,000 miles???
I'd say that that is unrelated to fuel quality as knocking damages much more inside the engine than just the valves. Pistons, cylinders, head and spark plugs all suffer.
Do you know a reason for that low mileage?
My opinion is that the higher octane number is only necessary if the manual calls for it. For your car 91 is not mandated rather recommended, meaning the engine tune and management can cope with it.
Things become different for engines which are highly strung, but then the manufacturer will mandate the higher octane fuel.
Your car's catalytic converter may just be wearing out at a normal rate.
Oh, and the lower octane rating really shouldn't matter when you're just cruising along at part throttle. Driving uphill in too low a gear ("lugging" the engine), or asking full power all the time is where knock comes into play. Then the 91 recommendation does make sense.
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Your engine compression ratio is 10:5 to 1. Using a grade lower than 91 will almost certainly cause knock. Of course, the engine hears the knock before you do, thanks to the knock sensor, and the computer retards the timing. Retarded timing results in incomplete combustion, which results in degraded performance and unburned hydrocarbons. Unburned hydrocarbons shorten the life of the cat.
Shorten,however, is a relative concept. You’re driving a 22 year old car. Squeezing a few extra miles out of it by paying for a premium grade fuel (and maybe avoiding a third cat or another valve job) is probably worth it. And the car will probably run better.
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Yes.
The sophisticated engine management system can adjust for the lower octane fuel. From the owners manual of your car:
"Volvo engines are designed for optimum performance on unleaded premium gasoline with an octane rating. AKI of 91, or above...The minimum octane requirement is AKI 87 (RON 91).
So even for the high pressure turbo "T5" variants, mother Volvo says 87 will do.
--
XC60 / Odyssey
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posted by
someone claiming to be Hugh
on
Fri Jan 8 23:11 CST 2021 [ RELATED]
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rehsper,
Thank you for reply. You have removed some regret/stress that I might have been unintentionally damaging the engine of my '99 XC. I may be foolish, but I plan to use 91 octane going forth. Two valve jobs and a potential catalytic converter will buy a lot of 91 grade gasoline.
Again, thank you for your reply.
Hugh
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Not foolish at all! It is what they recommend after all.
Drive confidently (and defensively) and have a nice day.
--
XC60 / Odyssey
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posted by
someone claiming to be Hugh
on
Wed Jan 13 15:50 CST 2021 [ RELATED]
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Rehsper,
Thanks. You'll be happy to know, I went out to my XC70 and re-read the owner's manual and confirmed what you said. It was reassuring to see "87 as a minimum". I like this Volvo. There is emotional attachment to it. Back in 1999 I purchased this Volvo used from the original owner with just 12,0000 miles on it for my father-in-law. At the time he was driving my two daughters, who were 4 and 3 years old at the time everywhere at that time. I wanted him to have a safe car. Two years after he took delivery of this car, another daughter was born, so he was driving my three girls around it it. He liked the Volvo because of how quiet and luxurious it was (his prior car was a Toyota Tercel wagon). Later just before he passed away from cancer in 2006, he gave the Volvo back to me. My two other Volvos, both 1996 850 GLT wagons with manual transmissions, were difficult for my daughters to learn how to drive on, so they initially learned how to drive on the V70 XC because it was an automatic. They all passed their road tests in that Volvo. All the girls learned how to drive a manual, but my middle girl still prefers driving an automatic, so she likes driving this as her primary car. Because of the safety it affords, I have no objection. I know Volvos are mortal, just like their owners, but I hope to keep this car as long as I can. I guess that is another "unspoken" reason why I will pay the difference and run it on premium from now on. In some ways it "owes me nothing".
Thank you again for your response.
Hugh
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As a percentage of cost, the difference in price between grades is not as great as it was many years ago.
I do not drive a lot so I use Sunoco Ultra in all our equipment.
Perhaps that is why I never have trouble with small engines.
14 years ago we drove our '90 745 from Massachusetts to Foam Lakes Saskchewan to visit our daughter who was surveying frogs for Ducks Unlimited. We drove 4990 miles in 17 days. I always write the gallonage and mileage figure on every gasoline receipt.
One stop was at a station in an area that spoke french. I filled my car with a very low grade of fuel. When I figured out the mileage for each fill-up. my mileage was down by 5 MPG.
I have used Ultra for 740s, 850s and our current XC70s.
BTW - When we got home, we drove the extra 10 miles!
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Volvo recommends 91 so use 91. It will run better and almost certainly give you better MPG. Adding a few gallons of 95 now and then won't do it any harm either. If the 87 is causing the valves to run extra hot they may be the problem but I've no knowledge of that. The cat has to run hot to do its job but running over hot will shorten its life. Certainly 87 would prefer different ignition timing to 91.
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posted by
someone claiming to be Hugh
on
Thu Dec 24 14:40 CST 2020 [ RELATED]
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Derek,
Thanks. I value your reply. I am starting to think, even at this late date, I might be better served to spend the additional money: it works out to approximately $5 extra per fill-up to use 91 grade or higher. I thought for years, that with the 87 grade I may give up some engine power and gas mileage, but would not do any damage to the engine. Based upon the history of my '99 XC (two valve jobs) I may be wrong. The "CEL" has come on recently for a second time, and my mechanic confirmed the code triggered indicates the catalytic converter hasn't failed, but is not as efficient as it should be. To address this issue, and avoid purchase an aftermarket catalytic converter (Volvo doesn't sell a catalytic converter but there are NOS converters sitting unsold on the shelves of local dealers for approximately $1,500 - which is about the value of my '99 XC), I will be installing a O2 sensor extension. I hope it works. The current catalytic converter was replaced 8 years ago when it was damaged as a result of a collision. I wonder now, just like the valve jobs described above, did the 87 grade gasoline hasten the demise of the catalytic converter. Using 91 or higher grade going forward, may be the "better economy".
Hugh
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Of the specced fuel (aka always premium) I've always heard "it's a cooler burn".
It seems so borderline, it's not like people report burning valves all the time.
At the age of your vehicle maybe cooling system efficiency comes into play. Is it clean and conducting all the heat it should?
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