Page 221 Land Cruiser Toyota OEM Engine, Chassis & Body Manuals
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When to change spark plugs?
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Page 221 Land Cruiser Toyota OEM Engine, Chassis & Body Manuals
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The price is a bunch more than the Haynes or Chilton book you see at your local part store. After I spent about 5 seconds comparing manual cost with Lexus or Toyota labor rate per hour, I discovered it's a no brainer.
Replaced plugs at 159K in my 98. My guess is that the plugs were original.
I measured the gaps on the old plugs - labels on the first photo. The odd one is the .041 on plug 5 which was also significantly more discolored than the rest. I also had replaced the coil on plug 8 (the crush washer of which was very clean).
I measured the gaps on the old plugs - labels on the first photo. The odd one is the .041 on plug 5 which was also significantly more discolored than the rest. I also had replaced the coil on plug 8 (the crush washer of which was very clean).
Photos of even cylinder plugs
Some tools/tips I found useful:
1) The magnetic socket I purchased on AMZN was well worth the $22 (AMPRO T33390 3/8-Inch Drive by 16mm Spark Plug Socket with Magnet).
2) For cylinders 1-7 I was able to remove all the plugs with a 6" extension. I threaded the plug back in by hand with the extension on the magnetic socket. I could then put my wrench on the extension by just matching the ratchet plug with the extension socket.
3) For cylinder 8, I tried the universal setup recommended in the TLC FAQ article (which is quite good) but it wasn't working for me. I happen to have two 3" extensions so I just put one on the magnetic socket, threaded the plug on, and then put the second one on.
1) The magnetic socket I purchased on AMZN was well worth the $22 (AMPRO T33390 3/8-Inch Drive by 16mm Spark Plug Socket with Magnet).
2) For cylinders 1-7 I was able to remove all the plugs with a 6" extension. I threaded the plug back in by hand with the extension on the magnetic socket. I could then put my wrench on the extension by just matching the ratchet plug with the extension socket.
3) For cylinder 8, I tried the universal setup recommended in the TLC FAQ article (which is quite good) but it wasn't working for me. I happen to have two 3" extensions so I just put one on the magnetic socket, threaded the plug on, and then put the second one on.
None of the plugs felt loose on removal - everything was quite snug which is the opposite of what I would have expected given the discoloration. There was dried oil on the tube of #5, I'm wondering if in part the oil was coming from the plug tube seal - oil leaking from the top and being vaporized/ 'cooked' on the plug. The coil on that cylinder was discolored as well. I'm going to replace the coils on 3 & 5 as a PM.
RoboRed - thanks for the write-up. I used it save for the universal aspect (It wasn't working for me and I didn't want to force things so came up with the use of 2 3" extensions on #8).
Since we're talking about spark plugs, do you guys use anti-seize when installing?
Determining if a spark plug loose is difficult, because they'll build carbon in threads from combustion gases escaping. So they may feel tight all the way out. This may also leave dried up oils in spark plug tube.
These combustion gases are suspected of cooking the coil boots and heating coil. Loose spark plugs also don't fire as well, which may causing the coil to run hot.
Typically, with leaky tube seals we'll see wet oil in tube, and just above gasket/washer on plug.
Checking in 5K or 10K for wetness in tube may be good idea. But my money is on loose spark plugs.
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I use anti-seize sometimes, very sparingly keeping away from tip.
I also wipe & blow off so that only residue remains, "out of concern" some may get into combustion chamber.
That brown ring stain on the insulator is what’s referred to as a corona discharge stain - oil particles being ionized due to the high voltage field around the plug. Ozone is also produced and that deteriorates coil boots.
I replaced my plugs over the weekend. The plugs from even numbered cylinders looked good- no staining. They came out quite easily.
The Odd numbered cylinders 1&3 were ok, 5 was very, very tight and 7 was tight. I approached #5 with fractional turns and stop then come back and try again 5 min later; took about 30 minutes of slow deliberate work to get that plug out- and it looked just like the #5 pictured above. You can also see the boot discolored. It crumbled into pcs. The tubes were clean, valve cover seals not leaking. You can also see the carbon build up on the bottom threads.
Curious to know others that are seeing stuck and discolored plugs on odd number cylinders 5 & 7.
The plugs were last changed 85k ago in 2010. I think its a good idea to inspect them every so often and re torque. Maybe replace sooner than 90k.
I used a copper antiseize very sparingly thin coating on the upper threads of the plug and wiped off excess. Mainly to lube the threads going into the head.
I also replaced all of the coil boots and donuts that sit at the base of the coil with the Denso kit. Did not replace the included spring retainers: they looked fine and the replacements are not easy to reset and can fall out.
Will inspect in 10k and see how #5 is looking.
Even side
Odd side
The Odd numbered cylinders 1&3 were ok, 5 was very, very tight and 7 was tight. I approached #5 with fractional turns and stop then come back and try again 5 min later; took about 30 minutes of slow deliberate work to get that plug out- and it looked just like the #5 pictured above. You can also see the boot discolored. It crumbled into pcs. The tubes were clean, valve cover seals not leaking. You can also see the carbon build up on the bottom threads.
Curious to know others that are seeing stuck and discolored plugs on odd number cylinders 5 & 7.
The plugs were last changed 85k ago in 2010. I think its a good idea to inspect them every so often and re torque. Maybe replace sooner than 90k.
I used a copper antiseize very sparingly thin coating on the upper threads of the plug and wiped off excess. Mainly to lube the threads going into the head.
I also replaced all of the coil boots and donuts that sit at the base of the coil with the Denso kit. Did not replace the included spring retainers: they looked fine and the replacements are not easy to reset and can fall out.
Will inspect in 10k and see how #5 is looking.
Even side
Odd side
You bet...either the copper or nickel varieties. No more than a paper match head or 2 spread evenly over the threads. Any that might remotely get into the combustion chamber will be consumed and quickly blown out of the exhaust.
You bet...either the copper or nickel varieties. No more than a paper match head or 2 spread evenly over the threads. Any that might remotely get into the combustion chamber will be consumed and quickly blown out of the exhaust.
This is how I justify most of my tool purchases... and the knowledge gained is priceless. If you enjoy turning wrenches, that is the best way to build your tool collection
