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S80 V8 Spark Plugs

4K views 7 replies 7 participants last post by  bluestreak614 
#1 ·
I have about 70,000 miles on my S80, and the fuel mileage has dropped significantly, so I think that it's time for a tune-up. I have a set of spark plugs for it. The front bank of cylinders will be a piece of cake, while the rear bank is more of challenge, but I've done worse. :rolleyes: My copy of VADIS only mentions a torque spec (25 nm) for the plugs. I can't find a gap measurement. (Maybe that's my fault) Are the Volvo plugs pre-gapped? Do I need to be concerned about it? Thanks in advance!
 
#3 ·
I have about 70,000 miles on my S80, and the fuel mileage has dropped significantly,
Not that changing the plugs no isn't a good idea, but this MPG drop is likely due to fuels switching to winter blend, rather than the plugs suddenly performing a lot worse.
 
#5 ·
Maybe it's my style of driving lately but I've seen a bigger drop in winter mileage than usual. With my 5 cyl Volvos I would go from 22 summer mpg to 20-21 in winter. The S80 has gone from 18-19 mpg to 14-15 this year, which I didn't see the two previous years. Access to rear plugs is complicated by 2 lines running over them. UGH! The electrodes on the first plug I pulled looked OK but the insulator had a corona, something I had not seen before. It's not supposed to indicate a problem.
 
#7 ·
I seem to be blowing through fuel at an unbelievable rate this winter in both my S80 and XC90. My highway mileage has dropped by about 4mpg in my S80.
 
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