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Here are my plugs at 82k. They were pretty easy to do with The Car Care Nut’s video. There are slight variations with the RX but pretty easy to figure out.
Six plugs at 82k Surge tank
Ah, so they are iridium!
I wouldn’t change these plugs at any less than 100k miles or you are wasting your time and money.
There’s a guy with a 4cyl Tacoma with OEM iridium plugs who drive 700,000 miles before they gave out. Not saying this is applicable to our vehicles but still, it’s a proof of durability…
Everyone can do whatever they want, I changed them at the mileage I specified. It wasn't a hard procedure versus previous generations and I'd do it again in a heartbeat.
It is interesting to note that in Canada the first spark plug change for both the RX350 and RX450h is required at 192,000 km (120,000 miles). I'm not sure why our interval is so much different.
Just speculating, but does the constant start/stop behavior of a hybrid ICE wear or foul parts like this faster? I have heard this suggested as the reasoning for keeping the oil change interval the same for both models.
For the start/stops, it would be better to have less worn spark plugs. It just makes for a more efficient/faster start and cleaner burn. But still, these iridium spark plugs do last a long time...
That's probably why they mention the emission control. Less worn spark plugs produce less pollution with a more efficient and complete burn.
The video posted by earlier on youtube by "The Car Care Nut" is fantastic but i wanted to list out a couple of the highlights for those looking at doing this
- you can tell if the spark plugs are original if they have a mark (such as a white letter N or M) marked on the very top of the plug - this could be useful for those trying to tell if the previous owner already replaced the plugs or not. (Forward to the 10:55 minute in the video to see an example of the mark)
- These plugs don't require anti- seize, the Denso 3491 (FK20HBR8) plugs these engines call for are nickel plated and are designed to run WITHOUT anti- seize.
- Torque spec for the spark plugs themselves is 13 ft-lbs.
- plug COIL mounting bolt torque spec - 7 ft-lbs (Note - the coils attach to the plastic valve cover, dont over torque)
- Yes, you need to remove the intake plenum, but it's not difficult. (New Gasket is required, it's a 1-piece gasket) Torque spec is 13 ft lbs. OEM part # for the 2016 model year is 1717631130, not sure if its the same for other years, but probably is, I couldn't find any aftermarket gasket options available)
- you do disconnect the throttle body from the plenum, torque spec is 7ft lbs. (Should replace gasket while you are here, just a couple $s OEM part # 22710P020, also available from Fel-pro #61445, Beck/Arnley #0039072 or Mahle #G32456) No need to disconnect the coolant lines from it, just disconnect the TB from the plenum and set it to the side.
- IMHO the Total time for most DIY mechanics to replace the back 3 plugs is probably under 1 hr. Front plugs are super simple and will probably take 10 min top.
Plugs ran me about $13 each, plenum gasket approx $25 and TB gasket approx $3 - total of about $110 for parts depending on your source.
Last edited by 396chevy; 01-08-22 at 07:47 PM.
Reason: spelling
First 3 plugs changed at 127K miles. I don't have the required gaskets yet so i did the easy 3 up front. These photos show the worst of the 3 I pulled out. No marks on the end so I'm not sure if they have been changed before.
Hi guys, I was a strong believer that the spark plugs would last till 100k mi, but I experienced a misfire (a single instance) at 72k mi so I went ahead and changed them.
Photo #4 appears to show a fractured ceramic shoulder on the plug -- that loose piece didn't help that cylinder. Did you faithfully use Top Tier gasoline only, or is there a possibility that some lesser quality gas is involved?
I have used nothing but Costco 87 except a handful of times. I live in close proximity to a Costco that's not busy ( unicorn emoji) until gas prices went ridiculous.
Here is an "OMG FML why did I attempt this after drinks" moment from last night. Look at how clean those valves are though.
Of course, then the question is, does the dirty appearance from wear of a spark plug have any correlation at all with its ability to spark properly? You could look at your synthetic oil after 4-5,000 miles and it would look dirty but it would still be lubricating perfectly fine. You could also have a defective spark plug that looks like new but isn't functioning properly.
For those who have the 4th Gen RX450H its a different kettle of fish , getting at the back plugs ....................... After the plenim you have to remove the EGR manifold and cooler and the wiper motors and tray etc for access .
Also The hybrid can have misfires due to carbon around the Port injectors . This is audible for the first 30 seconds on start up before the Direct injection takes over . Can be quite an aggressive shake .
I just did this job on a 2017 F sport rx350. It takes about an hour with all the right tools and some experience. It was not hard at all.
You need the throttle body and an intake manifold gasket with 6 plugs. There is 1 12mm bracket under the TB just remove that bolt and the manifold comes off in ten minutes.
Don't listen to all these tinfoil hats saying that these cars were designed to be tough to work on. Or that these don't need plugs done and that its a revenue generator.
Any car with variable cylinder technology will foul plugs and needs a plug interval cut in half. Thats why the gen before had much larger intervals. Doing the plugs also
maintains the emissions warranty. Its an easy job. Just do it.
I just did this job on a 2017 F sport rx350. It takes about an hour with all the right tools and some experience. It was not hard at all.
You need the throttle body and an intake manifold gasket with 6 plugs. There is 1 12mm bracket under the TB just remove that bolt and the manifold comes off in ten minutes.
Don't listen to all these tinfoil hats saying that these cars were designed to be tough to work on. Or that these don't need plugs done and that its a revenue generator.
Any car with variable cylinder technology will foul plugs and needs a plug interval cut in half. Thats why the gen before had much larger intervals. Doing the plugs also
maintains the emissions warranty. Its an easy job. Just do it.
I just did this job on a 2017 F sport rx350. It takes about an hour with all the right tools and some experience. It was not hard at all.
You need the throttle body and an intake manifold gasket with 6 plugs. There is 1 12mm bracket under the TB just remove that bolt and the manifold comes off in ten minutes.
Don't listen to all these tinfoil hats saying that these cars were designed to be tough to work on. Or that these don't need plugs done and that its a revenue generator.
Any car with variable cylinder technology will foul plugs and needs a plug interval cut in half. Thats why the gen before had much larger intervals. Doing the plugs also
maintains the emissions warranty. Its an easy job. Just do it.
When you say "variable cylinder technology", if you are referring to variable cylinder management (VCM) then, Lexus does not use it.
09-01-21, 09:02 PM
