The way I read the manual for my 1997 960 sedan is, Best performance with premium gas AKI of 91 octane. The minimum octane requirement is AKI of 87. Seems to me that Volvo wouldn't set the minimum at 87 if it could cause burnt valves, (like someone told me would happen). Don't remember where I heard it. What do you think?
Thanks, John

 

Well you also have to remember the 87 octane gas is not what it used to be back in 97 when the car came out.
Now there is a ethanol in the gas which is messing some of the cars up by itself. So the gas really isn't burning as clean as it was back in 97.

Also the gas of today is messing up parts in the car already. So down the line it is going to be even worse.

 

Thanks for the info. I also talked to another Volvo mechanic who said 89 octane is ok but 87 octane after a while would cause damage. If todays gasolines are going to cause damage to these cars, are we all going to have to go back to cheaper low performace cars we don't want? I will use premium from now on. 89 octane in a pinch, and 87 octane only if I have no other choice. You people always enlighten me about these things of which I know little. I am learning and give you many thanks.
John

 

If you have to run the lower grade gas what I have done when I was in the pich of having to do it was added a really good fuel system cleaner. This way all the build up on the valves it taken off. Alot of times there is alot of build up on the valves before it burns the valve.
If you keep the valves clean that will lessen the chance of it burning.

I will keep doing what I have to for keeping my cars running. Not sure if I would go back down to the cars I don't like.
I think I would take the bus first.

 

Of the many fuel system cleaners, all of which claim to be the best, what have you had the best results with?

 

Techron

I have used that in my Mustang the most and felt a difference within 2 miles everytime!!!!

 

Are you talking about a product besides the additive in Chevron gas?

 

You can buy a bottle of just the additive that goes into the tank. Walmart even sells it. It is a little expansive but works great.

 

Thanks, I'll give it a try.

 

Ethanol is alcohol, so wouldn't that clean the fuel system too?

I run 85 octane in mine. I've experimented with premium and midgrade and track all my mileage religiously, and no difference in mileage or performance. Of course, I don't drag race it. I commute to work and get groceries.

The main reason behind "best performance" is that the ECU can advance the timing a bit with higher octane fuel, which will bump the HP a notch, but with the lower grade gas, if the ECU senses knocking, it'll back off the timing.

Build up on valves would indicate an engine not running properly, no?

 

I run premium in mine as much as I can (all the time now that gas isn't $4.00 a gallon), and I can definitely tell the difference between it and regular 87 octane. Have never put additive in it, but might try some techron since Tech recommends it...