...so when I brought my GS to the Lexus dealership for an oil change and new tires, they said at 60K it's recommended to have the spark plugs changed. I declined because the engine runs smooth as silk and gas mileage is as good as I've ever seen. I wasn't planning on change the plugs until 100K. Is this too long?

 

While the 'service interval' may be 60k miles for changing spark plugs, there is no harm in not changing them...unlike other service items like engine oil, filters and various fluids. If you want to follow the recommended service intervals for spark plugs, that's perfectly fine...but those OE spark plugs will still be performing just like new ones far beyond double the recommended service interval. Iridium spark plugs will last well over 200,000 miles with no diminish in fuel mileage or performance.

Replacing the spark plugs at 60k miles is 'Required under the terms of the Emission Control Warranty'. Therefore, if you are not concerned with voiding the Emission Control Warranty, then there is no need to replace the spark plugs. I personally would not replace the spark plugs.

 

Its pretty ridiculous they recommend changing plugs at 60K miles, they should easily last to 100-120K miles as long as you use decent gas. I do remember test driving a LS460 with only 58K miles and it idled kind of rough, the dealership recommended new plugs and injector cleaning service when I did a PPI.

 

I did my spark plug at 60k mile but I did it myself and did the tranny and diff fluid too.

 

As others have said, Iridium Plugs can easily go 100K miles.
In our 2006 TSX I swap them at 80 to 90K. Does it help? If I say yes, people will scream...

Putnam Lexus in Redwood City, CA just performed the 60K service under CPO.
My wife drove the car, because I had recent surgery.
She sez no real difference, but they sure did a nice detail!

All good.
Going forward, I will do all the services myself.

 

We have the 2017 V6 RX450h. I'm reasonably handy and planned to change the plugs myself today - but on inspection found that only the front 3 plugs seem easy to get at. The back 3 seem to be well under the cowl and access is inhibited by manifold part(s). Removing all that is a little daunting, and I can't find any video help for the 2017. Anyone have any pointers?
Thanks in advance...

 

Here are a couple of videos for the RX spark plug change. Not specifically for the 2017 but, it's probably a very similar procedure. The first video is short and skips a lot. The second is more detailed. I had a similar issue with my former V6 Camry. I found a video that helped me change the back 3 plugs without removing the plenum. It wasn't easy but, I got i done and saved a lot of money on a job that should be very simple. So, I feel your pain! Good Luck!
1. 2.

 

So, what was the verdict upon inspection? I've never changed iridium plugs on an unleaded late model before 100,000k without good reason and I've never had a good reason.

That second video looks like. My user name is truncated KnuckleBusted. I leave DNA on everything I work on.

 

LOL, yeah I shed some blood too changing those back spark plugs and my forearms were all mangled up and sore for a couple of days. The middle plug was the hardest to reach. I considered mentioning it but, I left it out... until now!

 

No need to change for performance.

Denso Long Life which are the OEM plug will last to 120,000 miles

”Denso Long Life Iridium Plugs have iridium center and a platinum ground electrodes. If installed in a regular engine, they would likely last longer than most people keep their car (barring any motor problems that can cause premature plug death). All Denso long life iridium spark plugs are an OEM design, made for a specific engine. Some feature a special resistor or electrode design, depending on the OE requirements. In their OE application, Denso's long life plugs can last up to 120,000 miles.”

 

This.
Myself I went ahead and changed mine myself even though I firmly believe it wasn’t necessary.
It simply was an expensive car for me so I will just follow the maintenance schedule to each point.
Even the crazy 20k mile rear end oil change.
In the end it’s really not much money.

 

Taking mine in today for this service.

 

Please post your results and price of service. I bet it ain't cheap, over $1,000 at least.
Good luck.

 

$1,056.53 and that's with a coupon worth $150. I had them skip wiper refills since I had done them a few months ago as well as the engine and cabin air filters. It did include the spark plugs, brake fluid exchange, rotate/balance, oil change and then something they called "SDC ENGINE PERFORMANCE SERVICE - RESTORES COMPRESSION, REDUCE OIL CONSUMPTION AND CLEANS COMBUSTIO ~|~SDC ENGINE PERFORMANCE SERVICE - RESTORES COMPRESSION, REDUCE OIL CONSUMPTION AND CLEANS COMBUSTION CHAMBER ENGINE ASSURANCE PLAN COVERAGE".

$1k is where I wanted to come in on this service so not too bad and yet not a cheap service either.

 

Sounds like

1. Fuel injector cleaner
2. Oil change
3. Tire rotation
4. Brake Fluid flush

will go to my mechanic for 2 through 4 at 60k mi. ( 1 I will skip)