Spark Plug Change
01-15-19, 08:26 AM
#16
This vehicle was supposed to come from the factory with Denso FK20HR11 iridium spark plugs installed. I have not yet pulled one of the front plugs to check, but I indeed will when I do the 35,000-mile service.
I know iridium plugs typically do 150,000 miles or more on most vehicles they are installed in. But it is still a drag to have to remove the intake manifold just to change spark plugs.
I know iridium plugs typically do 150,000 miles or more on most vehicles they are installed in. But it is still a drag to have to remove the intake manifold just to change spark plugs.
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Cruisinthr (10-11-20)
01-15-19, 12:42 PM
#17
Instructor
I did it WITHOUT removing the intake. I think that technically, it would be easier as there's some reaching around you have to do with the intake on, but to me, the less components you have to mess with the better. I did not want to take off the intake and replace intake gasket only to find I might have not torqued it right or had a faulty gasket out of the box etc. I do not believe I have an intake leak based on smoke testing and the carb spray trick, so I opted to leave it alone.
https://www.clublexus.com/forums/rx-...ug-change.html
RX in NC, you gots a long way before you need to change yours.
https://www.clublexus.com/forums/rx-...ug-change.html
RX in NC, you gots a long way before you need to change yours.
The following users liked this post:
Petof (01-16-19)
01-17-19, 06:29 AM
#18
Intermediate
This vehicle was supposed to come from the factory with Denso FK20HR11 iridium spark plugs installed. I have not yet pulled one of the front plugs to check, but I indeed will when I do the 35,000-mile service.
I know iridium plugs typically do 150,000 miles or more on most vehicles they are installed in. But it is still a drag to have to remove the intake manifold just to change spark plugs.
I know iridium plugs typically do 150,000 miles or more on most vehicles they are installed in. But it is still a drag to have to remove the intake manifold just to change spark plugs.
01-17-19, 08:06 AM
#19
budwom,
Who said anything about replacing the spark plugs now? I did not like what I saw when I removed the dust covers because it looked to me like the plenum intake has to come off in order to change the three rear plugs. So I posed the question. It will be years before I change the plugs in this vehicle. I like knowing what I will be dealing with long before I have to do the job.
Who said anything about replacing the spark plugs now? I did not like what I saw when I removed the dust covers because it looked to me like the plenum intake has to come off in order to change the three rear plugs. So I posed the question. It will be years before I change the plugs in this vehicle. I like knowing what I will be dealing with long before I have to do the job.
03-27-19, 10:20 PM
#20
Driver
Just wanted to add some tips to this thread. I did the spark plugs on our 2010 RX350 today at 114k miles. They looked ok but it idles smoother on the new plugs. It is my wife's daily and not mine, so I can't comment on drivability, and not enough miles for mpg determination.
Resources I used include a 2nd gen Highlander 3.5 spark plug DIY, this thread, and the YouTube video with the gold RX claiming it was a faster way to do the plugs (did not remove intake)
It took me about 4hrs and I'm usually a slow worker. Because of the awkward angles, plan to be sore and scratched up. It is tedious but not complex. Just be methodical, work through it slowly but surely, take your time to not miss anything. Surprisingly, I didn't have to use a bunch of crazy flex joints. I think I only used a 3/8 drive u-joint for the 12mm bolt in the bracket on the passenger side, right over the coil. Everything else was mostly reachable by 6" extension and/or deep sockets, if I recall correctly. I did use a 1/2" drive breaker bar and impact sockets for the 14mm shock mount bolts in the cowl. Note that when working with the bolts in/near the cowl, you should be cognizant of what direction you apply pressure to your tools. You do not want your tools to fly towards the windshield in case they slip off the bolt. Chip the edge of the glass, and you'll be out more than the dealership would charge to do this job.
I removed the cowl and associated parts, I did not remove the intake manifold or anything else other than the plastic shrouds and a vacuum hose on the intake plenum (intake tract, throttle body, etc were all untouched). It is tight but it is doable. You do not need small hands - I weigh in at over 300lbs and 6'2", and the space wasn't the hindrance so much as working blind.
Speaking of working blind. The various clips and connectors behind the intake plenum are troublesome. Mine were all on there real good, and took a lot of force to remove. To make sure you're fighting the good fight, use the front bank as a proxy. The connectors are mostly the same, and you can see everything. By practicing here, you ensure that you get a feel for when it actually unclips. This was particularly helpful with the gray clips that secure the bulk of the harness (3 of these in the back, uses a smallish flathead screwdriver to unclip). Also, if you need help unclipping an electrical connector, I used a set of needle nose adjustable vice grips. This way, you can set the jaws to clamp down just enough to unclip the clips, and not hard enough to break anything. Use the front bank connectors to set the jaws width. This was a huge help, particularly on the sensor near the middle coil (I hear it is a cam position sensor). Bonus, once you clamp down and it unclips, you can use the vice grips to pull it out of the socket if you're lucky.
Also, use your technology if necessary. Most phone cameras take great pics, and can get into places where your head can't. Take pictures if you need to see what you're working on. I did, it helps. You can also use selfie mode if it gets you a better angle - I did not use this trick this time but have in the past.
I started at the passenger side of the wiring harness and unhooked everything as I went towards the driver's side. I made sure to unhook and unclip everything first, all the way to almost the throttle body, so that I could work unhindered, and it worked well for me. When working blind, make sure you run your fingers all along the harness so you know if there's an offshoot you missed. Don't just pull blindly in frustration, as there are reports of pulling the wires out of connectors. When you get near the throttle body, the wiring harness shoots off towards the center of the Vee, and I couldn't get to those connectors. So, be aware of those - it didn't hinder me, just don't try and pull the entire harness all the way out.
I did break 4 of the 6 coil connector clips off (the ones you push down on so you can remove the connector from the coil)...all 3 front ones and the driver's side in the rear bank. Oddly none were broken with the vice grips, just my bare hands. It doesn't seem to be a problem so far.
For greater clearance, I removed the passenger side hood strut and a vacuum hose leading to the brake booster. I forgot to reattach that hose and the Brake Malfunction lamp came on (I don't know why brake failure needs a light, it was bloody obvious...), so don't forget that. Do a brake check in your driveway to make sure - extremely high idle even for a cold engine was another tell that I missed. The light went off automatically once I fixed it.
As for the hood strut, mine are blown anyway so I put a vice grip on one of the strut rods anytime I'm under the hood (old mechanics trick I learned from an industry vet). The driver's hood strut with a vice grip on the rod held the whole time, without a passenger strut. I don't know if it would hold with just one good hood strut, but I doubt it. If you end up trying to remove the strut, do it after you remove all the plastic cladding on the fender. It gives enough clearance to make everything easier.
I also removed the safety latch on the hood because I kept running into it. Best two bolts I removed in this whole job, no clearance issues, not blind, not a lot of torque and kept me sane.
Other than the above notes, easy job!
Good luck
Resources I used include a 2nd gen Highlander 3.5 spark plug DIY, this thread, and the YouTube video with the gold RX claiming it was a faster way to do the plugs (did not remove intake)
It took me about 4hrs and I'm usually a slow worker. Because of the awkward angles, plan to be sore and scratched up. It is tedious but not complex. Just be methodical, work through it slowly but surely, take your time to not miss anything. Surprisingly, I didn't have to use a bunch of crazy flex joints. I think I only used a 3/8 drive u-joint for the 12mm bolt in the bracket on the passenger side, right over the coil. Everything else was mostly reachable by 6" extension and/or deep sockets, if I recall correctly. I did use a 1/2" drive breaker bar and impact sockets for the 14mm shock mount bolts in the cowl. Note that when working with the bolts in/near the cowl, you should be cognizant of what direction you apply pressure to your tools. You do not want your tools to fly towards the windshield in case they slip off the bolt. Chip the edge of the glass, and you'll be out more than the dealership would charge to do this job.
I removed the cowl and associated parts, I did not remove the intake manifold or anything else other than the plastic shrouds and a vacuum hose on the intake plenum (intake tract, throttle body, etc were all untouched). It is tight but it is doable. You do not need small hands - I weigh in at over 300lbs and 6'2", and the space wasn't the hindrance so much as working blind.
Speaking of working blind. The various clips and connectors behind the intake plenum are troublesome. Mine were all on there real good, and took a lot of force to remove. To make sure you're fighting the good fight, use the front bank as a proxy. The connectors are mostly the same, and you can see everything. By practicing here, you ensure that you get a feel for when it actually unclips. This was particularly helpful with the gray clips that secure the bulk of the harness (3 of these in the back, uses a smallish flathead screwdriver to unclip). Also, if you need help unclipping an electrical connector, I used a set of needle nose adjustable vice grips. This way, you can set the jaws to clamp down just enough to unclip the clips, and not hard enough to break anything. Use the front bank connectors to set the jaws width. This was a huge help, particularly on the sensor near the middle coil (I hear it is a cam position sensor). Bonus, once you clamp down and it unclips, you can use the vice grips to pull it out of the socket if you're lucky.
Also, use your technology if necessary. Most phone cameras take great pics, and can get into places where your head can't. Take pictures if you need to see what you're working on. I did, it helps. You can also use selfie mode if it gets you a better angle - I did not use this trick this time but have in the past.
I started at the passenger side of the wiring harness and unhooked everything as I went towards the driver's side. I made sure to unhook and unclip everything first, all the way to almost the throttle body, so that I could work unhindered, and it worked well for me. When working blind, make sure you run your fingers all along the harness so you know if there's an offshoot you missed. Don't just pull blindly in frustration, as there are reports of pulling the wires out of connectors. When you get near the throttle body, the wiring harness shoots off towards the center of the Vee, and I couldn't get to those connectors. So, be aware of those - it didn't hinder me, just don't try and pull the entire harness all the way out.
I did break 4 of the 6 coil connector clips off (the ones you push down on so you can remove the connector from the coil)...all 3 front ones and the driver's side in the rear bank. Oddly none were broken with the vice grips, just my bare hands. It doesn't seem to be a problem so far.
For greater clearance, I removed the passenger side hood strut and a vacuum hose leading to the brake booster. I forgot to reattach that hose and the Brake Malfunction lamp came on (I don't know why brake failure needs a light, it was bloody obvious...), so don't forget that. Do a brake check in your driveway to make sure - extremely high idle even for a cold engine was another tell that I missed. The light went off automatically once I fixed it.
As for the hood strut, mine are blown anyway so I put a vice grip on one of the strut rods anytime I'm under the hood (old mechanics trick I learned from an industry vet). The driver's hood strut with a vice grip on the rod held the whole time, without a passenger strut. I don't know if it would hold with just one good hood strut, but I doubt it. If you end up trying to remove the strut, do it after you remove all the plastic cladding on the fender. It gives enough clearance to make everything easier.
I also removed the safety latch on the hood because I kept running into it. Best two bolts I removed in this whole job, no clearance issues, not blind, not a lot of torque and kept me sane.
Other than the above notes, easy job!
Good luck
Last edited by N4TECguy; 03-27-19 at 10:34 PM.
The following 6 users liked this post by N4TECguy:
Cruisinthr (10-11-20),
johnnytam (11-16-19),
LONGSHORE (04-01-19),
RX in NC (03-28-19),
smknkeyz (04-03-19),
and 1 others liked this post.
03-28-19, 04:50 AM
#21
Thanks for the many tips. Not looking forward to this job, but the good news is that it is still many years away for me. My wife's 2015 RX350 is currently approaching 37,000 miles and she averages around 8,000 miles per year.
Were your factory plugs indeed iridium, and did you install new iridium plugs that matched exactly?
Were your factory plugs indeed iridium, and did you install new iridium plugs that matched exactly?
03-31-19, 10:17 AM
#22
Driver
Thanks for the many tips. Not looking forward to this job, but the good news is that it is still many years away for me. My wife's 2015 RX350 is currently approaching 37,000 miles and she averages around 8,000 miles per year.
Were your factory plugs indeed iridium, and did you install new iridium plugs that matched exactly?
Were your factory plugs indeed iridium, and did you install new iridium plugs that matched exactly?
I probably wouldn't wait too long to do your plugs. All of mine were really tight, so I bet the heat cycling got to them. I'd replace them earlier just to reduce the possibility of needing a helicoil.
09-09-19, 02:26 PM
#23
Best replacement Spark Plug??
I am going to change spark plugs on my 2010 RX350 at 124000. I want great plugs. Have seen many denso iridium at greatly different prices that fit. From $9ea 3526-FK20HR11 to "racing" 5749 at $28each . some with twin points--- -some with one point. Some called "long life -some called "High power" . Just what is best??? and how do I know they are genuine??
09-09-19, 02:45 PM
#24
I am going to change spark plugs on my 2010 RX350 at 124000. I want great plugs. Have seen many denso iridium at greatly different prices that fit. From $9ea 3526-FK20HR11 to "racing" 5749 at $28each . some with twin points--- -some with one point. Some called "long life -some called "High power" . Just what is best??? and how do I know they are genuine??
09-09-19, 03:52 PM
#25
Moderator
I trust you know it requires either removal of the intake manifold or the windshield wiper assembly.
09-11-19, 05:17 PM
#26
Intermediate
Just replaced mine for the first time for my 2011 (made in Sept 2010) at 231K KM (about 145K miles). C$100 for parts C$350 for labor + taxes, just over C$500 total. It is likely the last new set that this vehicle will see unless I decide to keep it past 500K KM. I looked at the different videos on how to replace it but I decided against DIY as we are a one-car family and if something broke or not done right, I'd never hear the end of it. Usual dealer perks - loaner, car wash, cappuccino.
Btw, I got the old set so I'll take a photo in case others are curious on how 231K KM plugs look like.
Btw, I got the old set so I'll take a photo in case others are curious on how 231K KM plugs look like.
Last edited by lex_rx; 09-11-19 at 05:22 PM.
09-12-19, 04:21 AM
#27
My experience with either Denso or NGK iridium plugs during the past 15 years or so is that they easily last more than 150,000 miles if the vehicle is properly cared for (meaning that the typical ongoing routine maintenance is performed in a timely manner).
09-12-19, 02:59 PM
#28
Instructor
I used oem denso iridium. No issues. I see no reason for racing or any other gimick like multiple electrodes. Doubt the coils have enough punch to really power multi-electrode plugs to take advantage of the design anyway
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raylor4 (03-17-20)
09-13-19, 04:40 AM
#29
OEM. Denso or NGK. Peace of mind.
