POLL + risk of delaying spark plug replacement? (1 Viewer)

What is your approx. spark plug replacement interval? (assuming stock LX470 plugs)

  • <60,000 miles

  • 60,001 - 90,000 miles

  • 90,001 - 120,000 miles

  • 120,001 - 150,000 miles

  • 150,001 - 180,000 miles

  • >180,000 miles


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Joined
Jul 21, 2017
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Austin, Texas
Hi,

I'm at 123,000 miles on a 2003 LX470.

The spark plug replacement was recommended at 120,000 miles.

What are the risks of delaying this replacement? Or is this something I should have done ASAP?

Thanks!
 
The biggest issue in my opinion is plug seizing in head due to carbon buildup on threads and not being able to easily remove it.
This is same type of problem one gets from never rotating tires. Wheels get seized [corroded onto hub] and extremely difficult to remove if you ever get flat and want to put on spare when on road.
Maintenance is always cheaper than repairing.
 
I voted for 60-90k. Truth is, you could go way longer with OEM plugs. Most simply carry a few spares and replace when one burns out (I see absolutely nothing wrong with that). I figure that plugs are relatively cheap and why not swap out all 8 every 60k (3 years for me). Seems cheap and easy preventative maintenance. I am coming up on that interval and will replace my coils with OEM as well.
 
There is a possibility of one or more plugs fouling. If so the ECU may shut down the engine to protect catholic converter.
I'd go with 60K change interval,cheap insurance. Alternately, frequent Italian tuneups will clean plugs.
 
Can't seem to find catholic converter in the parts database. Even tried searching for 'missionary.' Nothing.

Hopefully you used Safe Search for that one ;)
 
Iridium spark plugs are rated for 100,000 miles at the min, most new cars do not even have a replacement interval for the spark plugs, technically you can run them until you get misfires.
My wifes van has 182,000 miles on the original Denso Iridium spark plugs and it says right in the owners manual not to replace them until there is a problem, van runs fine and MPG is thge same as it's always been.
If it ain't broke...
In my truck I go every 100k.
 
"30K miles point to cleaning, inspecting and retorque" Replacing with Timing belt at 90K is nice, just to align with timing belt job.

The risk is spark plug gap widens with use. As gap widens it draws more current from the coil. The more current the coil puts out the hotter it runs. Coils running hot is number one reason coils fail, which cost ~ 10 x that of a spark plug.

New gap is 1.1mm
Max gap is 1.3mm
I like to replace once gap is ~1.2mm or sooner.

I've been finding a lot of spark plugs loose, even factory installed spark plugs. I find inner plugs (cylinders 3,5,4,6) loose so more than corners.

For this reason I'm going to start using 30K miles point to cleaning, inspecting and re-torque!
 
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First time I pulled mine at 120k miles, they looked and measured like new.
 
Just remember it is not generally problem with plug failing, todays Iridium spark plugs go a long time; it is more about making sure you can remove them when they do need replacing. I would rather replace early [60-90k] rather than chance stripping threads in head.
 
Id like to know more about the “catholic converter” and how effective it is inqusitioning exhaust gasses.

I think 90k would be max for me, and I like Pauls advice to check condition at 30k interval.

On my upcoming 180k service I dont plan to change coils, since techstream hasnt revealed any issues, but I did order the denso kit that has replacement ends and new gaskets since the ends of the coils tend to crumble, split apart with age and heat.
 
I’m still on original plugs at 195k miles. I’ll get around to it when it’s a little warmer. Been in the single digits here lately. Same serpentine belt too, starting to chirp, I’ll change that along with the tensioner and idler pulleys.
 
Some people never brush their teeth.....they can still eat but that don't make it right! :hillbilly:


Lol these trucks are bulletproof, I’ve been trying to break mine so it’ll give me a reason to get a 200 but it just won’t quit. Haven’t changed oil in 14k miles either and it runs smoother than my gf’s 50K miles benz
 
It is typical Toyota, they don’t break but they do wear. If you had the chance to drive a brand new 100 then you would see the difference, how close to new you want it to drive is up to yourselves to decide.
 
It is typical Toyota, they don’t break but they do wear. If you had the chance to drive a brand new 100 then you would see the difference, how close to new you want it to drive is up to yourselves to decide.
 

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