Spark Plug replacement DIY
04-14-13, 02:24 PM
#1
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Spark Plug replacement DIY
A tribute to scdroptop to attempted to coach some of us to do a Spark Plug change DIY quite a while ago! I miss scdroptop.
It was a rainy day in ATL (thank God the pollen was insane) so I decided to go for it. The SC had 108K to the day. I have had the spark plugs for 2 years sitting on my my drawer.
Took me about 3 hours and I was taking it slow. I have been somewhat intimidated by this DIY as I have seen a Lexus mechanic friend do it while he did the timing belt on another friend's SC. You have to have the right tools to get into the the tight spots.
The Plugs I used: NGK IFR6T11 Stock 4589 Laser Iridium Premium (which is the exact plug installed I would soon find out).
You will need a 5/8" Spark Plug Socket; 10 mm socket, rachet, extensions short and long. Stubby ratchets are a plus. I will show pics of my tools I used.
It was a rainy day in ATL (thank God the pollen was insane) so I decided to go for it. The SC had 108K to the day. I have had the spark plugs for 2 years sitting on my my drawer.
Took me about 3 hours and I was taking it slow. I have been somewhat intimidated by this DIY as I have seen a Lexus mechanic friend do it while he did the timing belt on another friend's SC. You have to have the right tools to get into the the tight spots.
The Plugs I used: NGK IFR6T11 Stock 4589 Laser Iridium Premium (which is the exact plug installed I would soon find out).
You will need a 5/8" Spark Plug Socket; 10 mm socket, rachet, extensions short and long. Stubby ratchets are a plus. I will show pics of my tools I used.
Last edited by mandyfig; 09-05-14 at 09:42 AM.
04-14-13, 02:47 PM
#3
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If you look at the manual it says 100K...not sure.
04-14-13, 02:54 PM
#4
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Here we go...
The battery and the battery tray must be removed. You will need the space to get into the plugs. As well as the Power Streering fluid reservoir must be set aside, I used a bungee cord to set it on the side, no need to take off. On the RH (Pass side), the oil dip stick must be off to get to the plug.
The battery and the battery tray must be removed. You will need the space to get into the plugs. As well as the Power Streering fluid reservoir must be set aside, I used a bungee cord to set it on the side, no need to take off. On the RH (Pass side), the oil dip stick must be off to get to the plug.
Last edited by mandyfig; 04-14-13 at 03:30 PM.
04-14-13, 02:56 PM
#5
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Progress...take your time, clean up as you go along...
The Stick Coils just pull out easy after you unbolt them. Cleam them up. The spark plugs are sitting tight but does not need muscle to unbolt. When bolting the plugs, use moderate tight feel to make sure the cruch ribs on the plugs sit on the cylinder head. I did not use a torque wrench as I knew how the plugs were tightened in. Check the manaul for the right torque if you need to.
The Stick Coils just pull out easy after you unbolt them. Cleam them up. The spark plugs are sitting tight but does not need muscle to unbolt. When bolting the plugs, use moderate tight feel to make sure the cruch ribs on the plugs sit on the cylinder head. I did not use a torque wrench as I knew how the plugs were tightened in. Check the manaul for the right torque if you need to.
Last edited by mandyfig; 04-14-13 at 03:10 PM.
04-14-13, 02:58 PM
#6
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Moving along...do not be intimidated, it is actually straightforward.
I numbered the stick coils, L means looking at the engine left hand and R for right hand. Numbers represent from left to right.
I numbered the stick coils, L means looking at the engine left hand and R for right hand. Numbers represent from left to right.
Last edited by mandyfig; 04-14-13 at 03:11 PM.
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Pep59 (08-20-18)
04-14-13, 03:00 PM
#7
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Some more notes and tips...
Very important, apply anti seize on the plugs. The plugs I removed had generous anti seize on them. They were in there tight but would give way with some decent torque.
Very important, apply anti seize on the plugs. The plugs I removed had generous anti seize on them. They were in there tight but would give way with some decent torque.
Last edited by mandyfig; 04-14-13 at 03:13 PM.
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04-14-13, 03:15 PM
#8
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When the plugs are in and the battery is in, before putting the cover back (in some cases the air intake system), start up and make sure it hums....
04-14-13, 03:16 PM
#9
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When everything works after multiple start and stops, replace everything in the engine bay.
Then it is time to re-set the power seat settings and the radio stations.
Then it is time to re-set the power seat settings and the radio stations.
04-14-13, 03:19 PM
#10
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scdroptop used to replace his plugs every 30K miles. Might be overkill but he says it feels that the ride is better every time he replaces the plugs....
With Laser Iridium, I think 100K would be the way to go. But to each his own way.
With Laser Iridium, I think 100K would be the way to go. But to each his own way.
04-14-13, 05:32 PM
#12
Lead Lap
Great job as usual Mandy. 40 years ago I would have thought it crazy to think that to change a spark plug would require removing the battery and the power steering reservoir. That is quite the ordeal just to change out spark plugs. Your old plugs did look to be in really good shape though, you were right. (Going back those 40 years again, you'd never find spark plugs in that good a shape as that, if you'd find anything left inside at all.)
Great documentation.
Great documentation.
04-14-13, 07:37 PM
#14
Advanced
Great write-up and excellent pictures. 
I replaced mine at 95 K and found the previous owner had them replaced before. I used the the DENSO IK20 plugs. They are rated better for performance but have a shorter service life ( 30 to 60 K ). Didn't feel any gains, so in retrospect, due to the amount of labor, the 100K plugs are a better choice. The anti-seize compound on the threads is real important, especially if you only touch them every 100K.
I managed to do the job without removing the battery ( plenty of various sized extensions & universals ), but there is some extra air intake plumbing on the non-modified engine ( w/o Injen intake ) that needs to come off.
I replaced mine at 95 K and found the previous owner had them replaced before. I used the the DENSO IK20 plugs. They are rated better for performance but have a shorter service life ( 30 to 60 K ). Didn't feel any gains, so in retrospect, due to the amount of labor, the 100K plugs are a better choice. The anti-seize compound on the threads is real important, especially if you only touch them every 100K.
I managed to do the job without removing the battery ( plenty of various sized extensions & universals ), but there is some extra air intake plumbing on the non-modified engine ( w/o Injen intake ) that needs to come off.
04-15-13, 06:10 AM
#15
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Thread Starter
Great job as usual Mandy. 40 years ago I would have thought it crazy to think that to change a spark plug would require removing the battery and the power steering reservoir. That is quite the ordeal just to change out spark plugs. Your old plugs did look to be in really good shape though, you were right. (Going back those 40 years again, you'd never find spark plugs in that good a shape as that, if you'd find anything left inside at all.)
Great documentation.
Great documentation.
I must say that the Sc430's engine is built rock solid, part of teh reason why the plugs are good after 100K.