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Yeah I know Lexus recommends changing the spark plugs on the GS every 60k but I’m just changing mine at 85k.. for these to be the orginial spark plugs at this mileage they actually don’t look bad. This is my 5th GS I hardly change them at 60k never had a problem. I also changed my drive belt since the mechanic is under the hood.
I thought the samething whats weird about it is that even on my 07 and 08 GS350 they look the same. I'm on my 5th GS now and for some reason they always look like that when they are removed. Its dry to the touch, the tech said everything was good nothing to be concerned about.
There would have been zero difference in fuel economy...
Just because Iridium plugs can "last" 160k doesn't mean the performance won't degrade over time. The electrodes don't just disappear in an instant once it ticks over 160k. Computers in modern cars can compensate for minor gap changes, but it comes at the cost of performance or fuel economy. We are talking about very fine tolerances here.
I had Iridium's from factory on my Civic Si. After 100k km, I changed out the plugs and they were at 0.06"(factory spec 0.043"). There was noticeable power difference and I got an improvement of 1L-1.5L per 100km. They too, "looked" perfectly fine. Only a feeler gauge would tell you the width changed.
Just because Iridium plugs can "last" 160k doesn't mean the performance won't degrade over time. The electrodes don't just disappear in an instant once it ticks over 160k. Computers in modern cars can compensate for minor gap changes, but it comes at the cost of performance or fuel economy. We are talking about very fine tolerances here.
I had Iridium's from factory on my Civic Si. After 100k km, I changed out the plugs and they were at 0.06"(factory spec 0.043"). There was noticeable power difference and I got an improvement of 1L-1.5L per 100km. They too, "looked" perfectly fine. Only a feeler gauge would tell you the width changed.
At 62,000 miles (100,000 kilometers) Iridium spark plugs will not show enough gap difference that can even be measured without sophisticated measuring equipment. You said your spark plug gap grew by 28% (0.043 ÷ 0.06 = 0.7167 & 1.0 - 0.7167 = 28.33 or 28%) from factory specifications, which is simply not believable. At twice the mileage (e.g. 120,000 miles) I doubt there would be a 5% gap difference, or a gap of 0.045 vs. 0.043, which is well within factory new specifications of ±0.003.
12-30-18, 09:03 AM
My Orginial spark plugs at 85k
