I did it on our 2015 a few weeks ago. I wrote about it above. Short story is that I have a number of vehicles with the 2GR-FE and usually remove the plenum as it is much easier to do with it off - not even a question. But on the 2015 RX, I stripped one of the plenum's hex head bolts and could not get it off so I had to replace the rear plugs with just the cowl removed. I got the job done but it was much harder and took a lot longer.

I would also add to clean the MAF sensor while the cowl is off as it is hard to reach on the RX version of the 2GR-FE compared to the Highlander version. I forgot to do that a few weeks ago so I had to remove the cowl again. I tried to avoid that by trying to remove the air filter box but after 20 minutes of trying, I could not get it off so I put it back together and pulled the cowl in about 10 minutes.

 

think it's doable without removing? plugs are already done. won't touch the maf if i have to remove the cowl.

 

Given the age of these vehicles now, always a good idea to clean the MAF sensor with the proper spray cleaner if you are removing the windshield cowl to do some other job.

But having to remove that cowl simply to clean or replace a MAF sensor is a stupid design flaw.

 

I did the plugs today on my 2015 with 120,500 miles. I also replaced the three rear coils, the plenum intake hardware (four Allen bolts, and two nuts) which were very rusty, the three plenum gaskets, and the throttle body gasket.

Thanks to the excellent videos available (ViktorG, Car Care Nut, and TRG), there were absolutely no surprises. The most difficult parts were getting the rusty plenum bolts out (I highly recommend an extended 5mm Allen socket that can be lightly tapped into each bolt to ensure proper seating) and getting the upper cowling back on. With my son's help, the job took about 3.5 hours. This time included teaching him a lot, but the time it took to teach him basics was paid back with interest by having the extra set of hands. We also took time to clean everything as we went (cowlings got cleaned and the back of the engine bay got a thorough hand wash. All and all it was a fun project to do together.

The famous plenum braket bolt at the back is no big deal with a swivel 12mm socket. I removed the lower bolt.

To make the job the easiest possible, we undid all of the connectors on the rear harness and slid it out of the way.

Happy to report that this 2015 with just over 120,000 miles model had a spotless throttle body and all spark plugs looked great. There was no buildup of any kind in the plenum. I had new coil plugs ready to go in case of any breakage, but they were not needed.

Thanks to the awesome community of Pros and DIYers that help make keeping these cars on the road so easy and rewarding!

______
2015 RX350
Chapel Hill, NC

 

Well done. I plan to wait until at least 150,000 miles to do this job on my wife's 2015 RX350 if we keep the vehicle that long. She is now approaching 108,000 miles.

 

The same here. We now have 105,000 miles on our 2015. I suspect we will keep driving it as I can think of no compelling reason to trade it and am slightly soured on what I'm seeing in newer cars.

 

Agreed. I do not want a 4-banger, a turbo, or a CVT. Hard to find a decent naturally-aspirated V6 SUV with a conventional transmission these days. Maybe a well-cared-for 2022 RX350 when the time comes. I believe that is the last model year with a V6, conventional transmission, and a CD player.

 

Exactly my thoughts.

 

I love my 2015 RX350 and it styling (inside and out). My only complaint was the radio/navigation interface which made it look dated. I solved that issue with a Grom VL2 upgrade . Now, I will just keep the RX350 running as long as I can instead of trading it for a new model.

 

Just did this on a friend's 2010 RX350 - put in NGK Laser Iridiums, cleaned MAF and TB + removed charcoal filter from air box. New gasket for plenum and TB and cleaned all the air box and intake hoses too which were filthy. Did not remove cowl or any of the rear ignition coil connectors - the less you disturb the better as these connectors love to break. Only a coulle hr job thanks to a 1/4" flex head ratchet w/ a 12mm socket. This was crucial to remove the bracket from hell off the back of the intake on the pass side after using a small pair of flatblades and some silicone lube to remove the connectors for the VVT-i solenoid and cam sensor on the pass side. Unlike my 08 RX350, you can pretty easily squeeze the intake plenum out from under the cowl with the bracket unbolted off the plenum, vs. my 2008 RX350 which is not as tall of a car and as such it has a lower cowl.

Agreed that the MAF sensor is in a STUPID spot, you can squeeze it out without taking the cowl off if you've got small hands. May as well just take out the air box anyway and clean all that up. I unplugged then unbolted the TB and cleaned both sides, leaving the coolant lines in to not make a mess. Never had an issue doing that on Toyotas. After the job make sure to reset the ECU. His average MPG went from 14.5 mpg to 19 mpg in city driving.

Overall - easier than 07-09 RX due to the larger engine bay

 

Well done.

I have monster-sized hands so any MAF cleaning or replacing will require me to remove the cowl. I will not be happy about it.

 

Yeah, the 3rd gen air box is such a disaster! It's beautiful to change filters on vs. the 2nd gen RX one which is from hell - but it's awkward to reinstall being tall and having vacuum lines out the wazoo.

I did the TB and MAF cleaning on our '14, but with only 100k miles, the plugs still look pristine! Maybe in another 50-60k miles or so I'll do them 😁

 

I will be changing my spark plugs soon on my 2015 RX350 and will just remove the intake manifold so that I can get a good look at the rear valve cover gaskets. I will also change out my rear coil packs for new Denso coil packs and save the old rear coil packs as spares for my front coils packs. Hopefully, my rear valve covers are not leaking(or weeping); if so then I will change out my rear valve cover gaskets as well. I will also change rear the VVT sensors as well.

If the spark plug coil pack connectors break so be it as that they can be easily re-pinned with new cheap plastic connectors. I had to re-pin two of out three spark plug coil connectors on my 2007 Highlander 3.3 V6 on the rear bank. I still have left over spare connectors that may work on the RX350 3.5 V6 spark plug connectors as well. You just need a very slim pick tool to push down the wire pin lock in the connector while pulling on the wire. I just swapped out one connector wires at time to ovoid any mix ups.

The Denso rear coil packs are still working in my 2007 Highlander 3.3V6 four years later. However, to be honest the OEM front coil packs are still working as well 18 years later; so the OEM coil packs are good quality long lasting units. The rear coil packs were still working as well when I swapped them out and are now my spares for the front bank. So the rear coil packs probably do not need to be swapped out unless they do fail.

 

Where are you sourcing your coil re-pinning connectors from? Back in 2018 I had to re-pin a VVT pigtail connector on my wife's 2006 Jaguar XK8 after I accidentally broke one of the factory ones while removing the factory alternator for refurbishment. I believe I found the VVT pigtail replacements at Rockauto.

 

To be honest just some cheap Amazon sourced units. They are still working or has not fell apart four years later on the old Highlander. The plastic seem to as good as the OEM connectors or good enough, however the cheap connectors will probably break when trying to remove them the next spark plug change( in about 6 years or 10 years total). I removed(unpinned) the cheap wires that are included and just use the plastic connector housings with the OEM pinned wires.