'15 RX350 Spark Plugs replacement - What else to do replace while i'm there?
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'15 RX350 Spark Plugs replacement - What else to do replace while i'm there?
My 2015 Lexus RX350 has 200,000 miles and original spark plugs! LOL Anyway, safe to say it's time to replace them!
I know the rear bank is going to be a complete pain in the *** to replace, so I'd like to replace everything while i'm there. Should I also do the 3 rear coils as well? They are expensive and still work fine so I'm hesitant to replace for no reason, but again, this is a big job so it almost makes me want to tackle it now.
Also thinking about doing the PCV while i'm there, any other small things I should consider?
Thanks
I know the rear bank is going to be a complete pain in the *** to replace, so I'd like to replace everything while i'm there. Should I also do the 3 rear coils as well? They are expensive and still work fine so I'm hesitant to replace for no reason, but again, this is a big job so it almost makes me want to tackle it now.
Also thinking about doing the PCV while i'm there, any other small things I should consider?
Thanks
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Joined: Oct 2014
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From: TX
Personally, I'd replace the coils. at least those 3. Also the electrical clips, they get fragile with age. Also any hard to get to hoses back there. If I was going to do this job, at 200K miles, I'd be thinking long and hard about removing the intake plenum and then probably do it. While off, soak it to remove buildup. I haven't looked at this lately, but recall plenum removal is straight forward, just a lot of stuff. Thats just me, I'm used to disassembling engines and putting them back together.
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I recently replaced my spark plugs on my 2015 RX350 with 190k miles and did changed out the coil packs and VVT solenoids on bank 1(rear side). I also changed out the bank 1 camshaft sensors.
However, be wary of using aftermarket sensors in the RX350. The Dorman VVT solenoids work perfectly in my 2015 RX350, but the Dorman camshaft sensors did not work in my 2015 RX350 as they triggered an engine service light for being too high of a value. Aftermarket Denso camshaft sensors do work in my 2015 RX350, but to be on the safe side use OEM camshaft sensors.
I installed Denso ignition coil packs and they work fine in my 2015 RX350. I also recommend using NGK Ruthenium spark plugs that has an 150k mile service life and better performance than the iridium spark plugs(120k mile service life).
I would also change out the PCV valve.
However, be wary of using aftermarket sensors in the RX350. The Dorman VVT solenoids work perfectly in my 2015 RX350, but the Dorman camshaft sensors did not work in my 2015 RX350 as they triggered an engine service light for being too high of a value. Aftermarket Denso camshaft sensors do work in my 2015 RX350, but to be on the safe side use OEM camshaft sensors.
I installed Denso ignition coil packs and they work fine in my 2015 RX350. I also recommend using NGK Ruthenium spark plugs that has an 150k mile service life and better performance than the iridium spark plugs(120k mile service life).
I would also change out the PCV valve.
Last edited by carguy75; Jun 25, 2025 at 11:30 PM.
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If you can get Ruthenium plugs affordably, try them. Switched the GS to them and I feel a differene, even against not-very-old iridiums. The NGK promises prove true, as usual IME.
Other things already covered, but I would personally not do the coils. The reason is that electronic components that are GOING to fail (weaker or defect inside) - they happen sooner rather than later. An example is that the coils in our oldest ES, w/340k miles on it, are all original. They’ve never acted up, and I don’t mess w/them. Only times I have had coils fail, have been closer to 100k miles or less. OEM coils are the only ones worth using, if you do got that route. I would definitely be doing the VCG, for sure.
Other things already covered, but I would personally not do the coils. The reason is that electronic components that are GOING to fail (weaker or defect inside) - they happen sooner rather than later. An example is that the coils in our oldest ES, w/340k miles on it, are all original. They’ve never acted up, and I don’t mess w/them. Only times I have had coils fail, have been closer to 100k miles or less. OEM coils are the only ones worth using, if you do got that route. I would definitely be doing the VCG, for sure.
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From: TX
If you can get Ruthenium plugs affordably, try them. Switched the GS to them and I feel a differene, even against not-very-old iridiums. The NGK promises prove true, as usual IME.
Other things already covered, but I would personally not do the coils. The reason is that electronic components that are GOING to fail (weaker or defect inside) - they happen sooner rather than later. An example is that the coils in our oldest ES, w/340k miles on it, are all original. They’ve never acted up, and I don’t mess w/them. Only times I have had coils fail, have been closer to 100k miles or less. OEM coils are the only ones worth using, if you do got that route. I would definitely be doing the VCG, for sure.
Other things already covered, but I would personally not do the coils. The reason is that electronic components that are GOING to fail (weaker or defect inside) - they happen sooner rather than later. An example is that the coils in our oldest ES, w/340k miles on it, are all original. They’ve never acted up, and I don’t mess w/them. Only times I have had coils fail, have been closer to 100k miles or less. OEM coils are the only ones worth using, if you do got that route. I would definitely be doing the VCG, for sure.
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If you are not concerned about peak performance and efficiency, Iridium is still very good. But not the best any more, and Ruthenium plugs are becoming more widely available.
Last edited by Oro; Jun 26, 2025 at 10:23 AM.
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Because ruthenium is better tech and delivers better performance via flame front control, all along the way. NGK has released it, Denso still behind the power curve on it. It’s newer technology and many people are not familiar with it, as you see.
If you are not concerned about peak performance and efficiency, Iridium is still very good. But not the best any more, and Ruthenium plugs are becoming more widely available.
If you are not concerned about peak performance and efficiency, Iridium is still very good. But not the best any more, and Ruthenium plugs are becoming more widely available.
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Joined: Dec 2013
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From: wa
By controlling the flame-front of the spark better, you get better and more complete combustion. It can make for performance gains in any engine. It’s more pronounced in a higher compression 2GR-FSE, but you will feel it in a 2GR-FE. NGK’s website has some info on it, high-tech real-life visuals of internal combustion differences, etc.
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Joined: Nov 2014
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From: TX
By controlling the flame-front of the spark better, you get better and more complete combustion. It can make for performance gains in any engine. It’s more pronounced in a higher compression 2GR-FSE, but you will feel it in a 2GR-FE. NGK’s website has some info on it, high-tech real-life visuals of internal combustion differences, etc.
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From: Massachusetts
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Because ruthenium is better tech and delivers better performance via flame front control, all along the way. NGK has released it, Denso still behind the power curve on it. It’s newer technology and many people are not familiar with it, as you see.
If you are not concerned about peak performance and efficiency, iridium is still very good. But not the best any more, and ruthenium plugs are becoming more widely available.
If you are not concerned about peak performance and efficiency, iridium is still very good. But not the best any more, and ruthenium plugs are becoming more widely available.
That is why I installed ruthenium spark plugs in my 2015 RX350 and so far my RX350 runs very well and have better gas mileage than with the older plugs as expected.
To be fair, my RX350 had 170k miles when I bought it used so I never ran it with new iridium sparks plugs to make a fair comparison. All I know is that my RX350 runs like a dream now with great acceleration and much better fuel economy with the Ruthenium plugs.
I am happy with the ruthenium plugs in my RX350. How much of an performance improvement new ruthenium plugs has over new new iridium plugs? I do not know or really care to be honest. The difference in plug performance (if any) is probably negligible or barely noticeable in normal driving conditions.
Last edited by carguy75; Jun 26, 2025 at 07:10 PM.