lobuxracer

iTrader: (2)

Lexus Scheduled Maintenance says replace spark plugs in the GS300 at 60k miles (just short of 100k km). In the GS 430, they say change the plugs at 120k miles, (a bit short of 200k km). So, the plug life Lexus anticipates for the V-8 is double what they expect for the V-6. Pretty shocking if you ask me, but that's what is documented in the US maintenance schedule.

ibidu1

iTrader: (1)

I believe there are two kinds of plugs from lexus iridium (higher mileage/more expensive) and non iridium (less miles/less expensive) the ealry GS300 had regular plugs. GS300 GS350 GS460 run the same plugs

lobuxracer

iTrader: (2)

Those numbers are a direct quote from the 2006 model year scheduled maintenance guide. ND and NGK claim 100k miles for their iridium plugs on their website, but I've never seen 120k miles for any plug ever before this. The 2UR-GSE has a 60k change interval and they're definitely iridium plugs.

MJG87

Interesting information. Obviously whats more important than stated intervals is inspecting/changing components when you feel any indication it may be warranted, i.e rough idle, poor fuel economy, changes to power delivery, misfiring under load etc.
I have used expensive iridium plugs in the past and seen them last as little as 25k miles, so I would take the manufacturers claims and the service intervals with a grain of salt and use them as a guide only. If they feel like they need to be replaced before then, then it should be done. I am approaching 70k miles on mine and will be inspecting and possibly replacing the plugs next service, more for peace of mind than anything else. I typically service everything early, but I have a history of owning modified turbo JDM imports and you can never be too careful.

lobuxracer

iTrader: (2)

On any modified turbo engine, everything lives a shorter life. Speed costs money. How fast do you want to go? Lexus service intervals are based on units in the OEM configuration operated under "normal" conditions. I don't expect the plugs in my Supra to last as long as Toyota expects with nearly twice the OEM boost.

MJG87

That's a given. I should be replacing mine in the next few weeks, car is at 70k Miles, I will take a picture for this thread to see what they are like.

Drcoffee

I always use anti-seize because the times it wasn’t used, removal was very difficult. Keep in mind, the threads maybe coated but the washer gasket is not. I have had cars where the gasket seized to the cylinder head. That was not fun trying to remove that without breaking it off into the cylinder. So I put a small smear on the first 5 threads, and coat the washer’s top and bottom surfaces. But once You do that, you have lubricated the plug threads and you can now over torque the threads. Reduce the book torque by 10%. If the book says 13#, lower the torque to 12#. I found copper anti-seize works better than the gray stuff.

energie8

I've never used it and its fine without.