I had regular copper plugs in my Subaru. I changed them after 5 years and 140k. Yea they were quite worn but there were no performance issues, nor improvements after changing them. And no trouble removing them. Just leave them in there. They'll probably last the life of the vehicle.
Replace Spark Plugs Based on Time, not Mileage?
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I've sure changed a lot of plugs in my life-most in the leaded fuel days when 6-10k miles were typical. Today, it's hard to get used to the new intervals and often harder to change the plugs-both access and removal. I do get nervous with dealing with the aluminum heads and some plugs have been quite 'sticky' to get out. I think in some cases the last thread or so can have carbon built up that makes it more of a challenge. Maybe some pre change combustion chamber de-carbon would help? I miss the days of a short tapered seat plug in a cast iron head!
Originally Posted By: Lapham3
I've sure changed a lot of plugs in my life-most in the leaded fuel days when 6-10k miles were typical. Today, it's hard to get used to the new intervals and often harder to change the plugs-both access and removal. I do get nervous with dealing with the aluminum heads and some plugs have been quite 'sticky' to get out. I think in some cases the last thread or so can have carbon built up that makes it more of a challenge. Maybe some pre change combustion chamber de-carbon would help? I miss the days of a short tapered seat plug in a cast iron head!
Ford has a TSB on their Triton 5.4 about pre-treating with PM-3 ( http://www.amazon.com/Genuine-Ford-PM-3-Carburetor-Tune-Up/dp/B000NU6RG8 ; cheaper at my local dealer ). Since I'm paranoid about spark plugs I plan on pouring a can down the wells the night before I change my plugs, backing them out a crack in the morning to let the PM-3 work in, and having even more on hand to soak with if I hit any stickiness when I take them out in the afternoon. I know, plugs shouldn't be a complicated multi-day process, but I'm paranoid about anything that threads into my cylinder head.
I've sure changed a lot of plugs in my life-most in the leaded fuel days when 6-10k miles were typical. Today, it's hard to get used to the new intervals and often harder to change the plugs-both access and removal. I do get nervous with dealing with the aluminum heads and some plugs have been quite 'sticky' to get out. I think in some cases the last thread or so can have carbon built up that makes it more of a challenge. Maybe some pre change combustion chamber de-carbon would help? I miss the days of a short tapered seat plug in a cast iron head!
Ford has a TSB on their Triton 5.4 about pre-treating with PM-3 ( http://www.amazon.com/Genuine-Ford-PM-3-Carburetor-Tune-Up/dp/B000NU6RG8 ; cheaper at my local dealer ). Since I'm paranoid about spark plugs I plan on pouring a can down the wells the night before I change my plugs, backing them out a crack in the morning to let the PM-3 work in, and having even more on hand to soak with if I hit any stickiness when I take them out in the afternoon. I know, plugs shouldn't be a complicated multi-day process, but I'm paranoid about anything that threads into my cylinder head.
Originally Posted By: bvance554
I had regular copper plugs in my Subaru. I changed them after 5 years and 140k. Yea they were quite worn but there were no performance issues, nor improvements after changing them. And no trouble removing them. Just leave them in there. They'll probably last the life of the vehicle.
Every time I changed plugs in my '02 Subaru Forester (2.5L N/A engine), the ones pulled were noticeably used/worn but not corroded or damaged. I showed one to a trusted mechanic once and he said I'd definitely see improvement in performance and fuel economy once I changed them. I never did notice any improvement, really. Even when spark plug seals were leaking. Thankfully before and after the change -- about every 3-4 years and 30k or so miles which what manual recommended -- MPG was still good and performance fine as well. Always used NGK coppers. Should probably extend the interval now that I am thinking about it...
I had regular copper plugs in my Subaru. I changed them after 5 years and 140k. Yea they were quite worn but there were no performance issues, nor improvements after changing them. And no trouble removing them. Just leave them in there. They'll probably last the life of the vehicle.
Every time I changed plugs in my '02 Subaru Forester (2.5L N/A engine), the ones pulled were noticeably used/worn but not corroded or damaged. I showed one to a trusted mechanic once and he said I'd definitely see improvement in performance and fuel economy once I changed them. I never did notice any improvement, really. Even when spark plug seals were leaking. Thankfully before and after the change -- about every 3-4 years and 30k or so miles which what manual recommended -- MPG was still good and performance fine as well. Always used NGK coppers. Should probably extend the interval now that I am thinking about it...
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Taking the plugs out for inspection every 5-6 years is sound practice...keeps the treads from corroding up and saving this:
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