Ticking time bomb TICK TICK TICK: Spark plugs Alert Alert Alert! (2 Viewers)

[2001LC]

TICK TICK TICK POP POP POP is a ticking time bomb, often mistaken as exhaust manifold crack or gasket leak leak.

ALERT, ALERT, ALERT: Spark plugs are working themselves loose. "Walking Out" Then blowing out of head, taking their female threads of head with them! Very damaging!

You think TICK or POP, is blown exhaust gasket or crack exhaust manifold. Replace the spark plugs. If tick doesn't go away, then you've confirm exhaust leak. Exhaust leaks anywhere need to be taken care of. But they're less damaging if damaging at all. But, if you blow a spark plugs out the head, you'll regret it and kick-yourself. As you now know it is an issue!

Be aware of sound of a loose spark plug. A tick, tick, tick or pop, pop, pop sound on cold start up, is early stage. That as they get looser (walk out more), sound does not go away once engine warmed up (ready to blow out of head). If you hear after engine warm, turn engine OFF.

What are we hearing and seeing, that are being caused by loose spark plugs.

• False exhaust (tick or pop) manifold leak sound. If you hear this, replace spark plugs as a first step in diagnosing. Better safe than sorry!
• Premature failure of coil boot.
• Premature failure of coil.
• Plugs blowing out of head. Damaging threads of head.
• May even be cause a burnt valve. (This might be a stretch)
• Cylinder wall, ring & valve damage. If debris falls into cylinder camber. Either during a spark plug blow-out, or after during typical repair with a Time-sert install.

For this reason I'm adding Checking Spark Plugs as a 30K mile or 3 years PM 90K mile or anytime tick heard.
It's more so about warm-up and cool-down cycles, than miles. So 90K miles with timing belt service, is good for most. Typically we don't see plugs blow-out earlier than 120K. But it can happen earlier, even at 30K miles.

You can just retighten. But replace, and your done for next ~90K miles or until tick, tick, tick. Spark plugs have a gasket (crush washer), which doesn't work as well (but does work) a second time. I'm using, 18ft-lbf torque (Toyota spec is 13ft-lbf) on "hopes" we can get to 90K, until recheck or replace.

"Do Not Use" Anti-seize even a lite coating on threads is a bad idea.

I say this, because I've found evidence this cause plugs to seize in the heads. It seems as plugs start walking out, the anti-seize cooks as it's mixes with hot combustion gasses. This then stop the walking out, but also causes threads to seize in the heads. They can still blow-out of the head.

With frozen in plugs. I've found I can tighten a bit then loosen a bit, repeat repeat repeat working in penetrating oil. About 1/16 turns each way working up to 1/2. After adding penetrating oil & 44k (44k to gas tank) and then repeat after few tanks with 44K has been run through. BTW: we should use 2 cans of 44K to a full tank of gas.


Sound of loose spark plugs is easily heard:

• Place ear at/in front fender well, on one side than the other. tick tick tick. Mostly heard and loudest on cold engine start-up.
• Have someone driveaway, stepping (do not floor it) on gas as if in a hurry. pop. pop. pop.
• Drive close to/along a wall, like a brick building or concert HWY divider. tick tick tick.

Note: If you've a hole in your muffler, it may mask or be confused with the tick.

When replacing spark plugs:

1. Blow off top of engine and blow out spark plugs tubes, before removing spark plug. It is best to snug them down, before blowing out the tubes. We do not want dust (sand) dropping in cylinders, as spark plug removed or installed.
2. Replace spark plugs, using ones from a known good supplier. So many bootleg plugs in the market, which they too can be damaging. Buy cheap get cheap, but high price is no guarantee. I use Dense IK20TT. Because the China bootlegger's (last I saw), can not reproduce the ultra this .4mm electrodes. So I can spot them, by comparing with any other spark plug. The TT, also starts with a narrower gap of 1.0mm. The tighter the gap, the less AMPs required for spark, the less heat produced. Heat is the enemy, of the coil(s). Replacement is best, but not needed if gap has not increased by 0.1mm. Factory new spec 1.1mm gap, replace at 1.2mm<. The Denso TT start at 1.0mm, replace at 1.1mm. Checking gap is and art, done with a very very lite touch. If your a gorilla, do not even check or you'll damage the electrode. I use 0.01 or 0.02mm less thickness feeler gauge(s), so I don't put to much pressure on electrode. If gap wrong or electrode look misaligned. It's likely a junk plug, boot leg, a return that was damaged or packaging damaged. It is best to return those. Only experts can change gaps and alignment.
3. I torque to 18ft-lbf, which is 5ft-lbf above factory spec. I do this in "hopes", they hold longer before walking-out. But spec of 13ft-lbf is fine too, with new spark plugs.
4. I replace coil boots and top seal, while in there. Boot contain the spark form bouncing around inside tube and top seal keeps tubes clean. Torque coil bolt to 66INCH-lbf, gives proper sealing pressure to top seal.
5. I retorque head cover bolts to 53INCH-lbf, while there. This stops most (98%) all head cover oil weeps

Repeat every time tick heard or 90K miles (timing belt service) on average. Keep in mind; it's not miles driven. It's about how many heating and cooling cycles.

TICK TICK TICK goes the time bomb!

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Be alert, so you don't see a spark plug blow out the head:

 

[cwmoser]

BTW, what is the recommended tightening torque?

 

[2002TLCyes]

Also, how do I get at them, to check them?

 

[flintknapper]

Do you mean "loose" as in the threads have actually backed off...or just slightly loose from the sealing ring on the plug having gone through heat/cool cycles?

 

[2001LC]

BTW, what is the recommended tightening torque?

Factory spec is 13ft-lbf.

But I'm using 18ft-lbf from a range Denso torque chart gives. Use this higher torque, at your own risk.

Also, how do I get at them, to check them?

If you have a high pressure air pistol. Use it to below out dust/sand from heads covers and each spark plug tube, before removing plugs.

Pull air box off RH side, and fuel line bracket's on driver side (bank 1) head cover near # 5 coil/spark plug, to gain access to all plugs.
Use a 10mm socket to remove bolt retaining air box, fuel bracket.
Clean top of engine. Blow dust off heads.
Then disconnecting wire housing blocks, from coils. By pinching release catch, as you pull off wire housing block. Blow out dust from wire housing block. Remove 10mm bolts from each of the 8 coils and pull out. Blow dust from coil while on the bench.
Blow out spark plug tubes. Best to sung plugs before blowing out tubes. We do not want dust/sand falling into cylinders past lose threads, or when spark plugs removed
If coil boot has/have a good seal, they tend to be a little hard to pull off coil, due to suction between boot seal on spark plug. Some coil boots may be cooked on and tear apart. A little rotational twisting, can help free coil boot from spark plugs
Then use a 16mm spark plug socket with various size extension, universal and 3/8" breaker bar to remove all plugs.

#7 (driver side near fire wall) spark plug is the one everyone complains is a PITA. It's not bad if you put a short 3" extension topped with a universal (swivel) connected to your 3/8" breaker bar or ratchet. The combo gives me the correct height, with the universal sticking up just above top of head cover so I can attach my breaker bar. I also have a spark plug socket w/permanently attached short swivel extension, that works very well.

Once plugs out (if reusing) I clean threads, with spark plug cleaner if reusing. With a $20 HF spark plugs cleaner, for 20 seconds at 90psi. A wire brush can be used to clean threads, being careful not to touch business end of the spark plug. Then blow off spark plug or rinse with gasoline, to clean oil and or debris. Final step is to check gap. Do not change gap of used spark plugs. Increase gap from use of .1mm replace them. Spec. 1.1mm (1.0mm on the Denso TT) is new, limited of used is 1.2mm (1.1mm on Denso TT). At or wider than increase of 0.1mm, replace. I replace if just approaching 1.2mm gap.

Remember, during install to always thread on by hand. By putting your extension on the plug socket tool without ratchet or breaker bar attached. If you've clean threads they will thread in easy.

Also, it is important to keep your extension of the socket wrench stable and centered in the spark plug tube at all times. You may break the porcelain of the spark plug if not.

Final torque to 13ft-lbf is the FSM recommended. I use 18ft-lbf.

Typical on new Denso I see a gap of 1.09mm

Do you mean "loose" as in the threads have actually backed off...or just slightly loose from the sealing ring on the plug having gone through heat/cool cycles?

I can say for sure if a combination of just loose at first, then walking off and blow out.

The washer (gasket) crushes on first install, so those are walking off. Here's the rub; Ones that have been loose for some time, threads may be carbonized. So they "may" feel tight all the way out. If you start by snugging down, and they turn. They where loose.

 

[2001LC]

I like to blow off loose sand & dust, even washes engine or before beginning. You must take care not to get any dust into heads. I also use an air pistol, to blow out spark plug tube, before removing plug.

Here a few pictures that may be helpful.

Air box removed reveals RH plugs #'s 8, 6, 4 & 2 (#2 front of engine).

Plugs #1, 3, 5, & 7 (#7 rear by fire wall) are accessible once fuel bracket removed.
Two 10mm bolts secure the fuel bracket that's in the way.

To remove coil pinch at top to release catch and pull off. I use a needle nose pliers to pinch and pry off with a wide blade screwdriver between bottom of wiring housing block & coil or a hook like screw driver to pull off. This must be done very very very gently or you will break the tab of clip or wire housing. Just take your time and go easy, they can get stuck from dirt jammed in it.
Once coil out. Use compressed air, to blow dust out spark plug tube.

Here is and example of coil boot premature aging from heat. Notice the two brown boots compared with the one good gray one.

The brown boot indicates prematurely aged. Can be seen cracking when squeezed and are no longer soft and pliable. Denso sell a boot& seal kit. Which I use with spark plug changes. Number one concern, even if they look good. Is the top seal. It keeps dust out, and water from washing in sand/dust.

 

[2001LC]

Here are tools I'll use.
You can do without the pliers & screwdriver. Also you'll find tools in your Land Cruiser tool kit with exception of torque wrench to do the job.

Oh and my 3/8" Universal. Use with the short (3") extension above for #7 spark plug. Works great.

This old tool is great for hooking on wire housing blocks to pull them off.

Here set-up for #7 & #8 plugs. Use breaker or ratchet to remove.

This has become my favorite style, which few different manufactures make. Has swivel build in, so can't separate while in the spark plug tube.

 

[YardPig]

Are the Denso's made in Japan or the USA? I've seen a lot of the Denso stuff manufactured in the USA lately. I usually stick to NGK.

 

[jerryb]

ngk is in the book also as oem reccomended

 

[TheForger]

Great advice on checking the torque I have never really thought the plugs would back out on their own. Just curious, why do you recommend not changing the gap of used spark plugs? I realize it will change how it fires but wouldn't disconnecting the battery for 30min or so and then letting it idle after you have it all back together correct this?

 

[flintknapper]

IDK. I can't say for sure if a combination or just walking off. The washer is crushed on first install, so I'm leaning toward walking off as primary. Here's the rub; Ones that have been loose for some time, threads may be carboned up. So they may feel tight all the way out.

^^^^^^^^ Agreed. While it is not impossible for the plugs to physically back off the threads, it would require poor contact with a coil 'boot' to do so. Good idea to replace the boots along with the spark plugs. Just about every one of mine had hardened from engine heat, last time I installed new plugs.

Not much that can be done about the sealing ring ....except to check your plugs from time to time.

**** BTW, judging by the color of your radiator 'top' you'll be needing a new one in the not too distant future.

 

[Spike555]

On #7 I used all my extensions and got my ratchet past the a/c lines.
That worked pretty well for me, just throwing that out there.
I also spray down into the spark plug hole with WD-40 or the like and let it soak for a few minutes before trying to remove the spark plugs.
You don't need much, just a quick squirt or two.

 

[SARguy]

UPDATE BELOW; Last July, I replaced two 80s with an 04 LX470 with 110,000 on the clock. In my base lining I replaced the plugs with denso iridiums. I used the FSM torque value of 13 lbs/ft to tighten. I also used a little antisieze specified for spark plugs. Since then, I thought I had developed the header tick on the Passenger side. Last week at 124,000 on the clock, and with all the posts on self loosening plugs, I thought I would check that first. Sure enough, All plugs were in various stages of looseness. One on the PS had some corona burning on the base of the outside ceramic. Most were little more than finger tight. Several had cooked oil/exhaust residue on the threads which I cleaned up. The exhaust tick went entirely away for a week. Now it is back. Does anyone know a safe torque value to use that will prevent this loosening?

I just went out and checked torque and passenger side plugs. I would say the breakout force to loosen the plugs ranged from 3 to 8 ft lbs. I have always used the strong arm method of tightening plugs before this car. Never had a problem with stripped threads, difficult to remove, or loosening plugs. ( that is over 8 different landcruisers.. 1F, 2F, 3F and four 1fz engines, not to mention several honda and toyota sedans. Never a problem. I always tightened new plugs to where I could feel the crush ring settle... plus a little more.

I just re tightened the passenger side to 16 ft lbs and the exhaust tick is gone again. I forgot to mention I have been able to smell a little exhaust , and re-torquing the plugs the exhaust smell is gone.
I will wait for a while before I check the drivers side.

 

[jerryb]

I wouldn't use never seize, but I understand why some would.

{{ title }} NGK website

Plug Torque Settings denso

 

[SARguy]

I wouldn't use never seize, but I understand why some would.

{{ title }} -NGK
Plug Torque Settings -denso

I have questioned myself of use of the anti seize. I think it comes from paranoia from when I have purchase a used car and have had to use so much force on my first plug removal, wondering if the threads, or plug would destruct. I have wondered if the anti seize is a factor, I have also wondered if I need to check the calibration on my torque wrenches. I have seen the damage a loose plug can cause and I hope someone out there can find a solution. 14,000 miles and finger tight plugs is downright un nerving.

 

[jerryb]

estimate 20% percent increase is what they say. denso and ngk.
In my work we go higher than that. Actually the engineer tells me, on hand torque at least.

One drop of never seize on the bottom face of the washer will change the value. I always went 1/4 turn + a nuge, not quite half a turn on cars.
That's just the way I do it. Doesn't mean it's right. I don't have an accurate certified inch pound wrench either.

 

[Spike555]

UPDATE BELOW; Last July, I replaced two 80s with an 04 LX470 with 110,000 on the clock. In my base lining I replaced the plugs with denso iridiums. I used the FSM torque value of 13 lbs/ft to tighten. I also used a little antisieze specified for spark plugs. Since then, I thought I had developed the header tick on the Passenger side. Last week at 124,000 on the clock, and with all the posts on self loosening plugs, I thought I would check that first. Sure enough, All plugs were in various stages of looseness. One on the PS had some corona burning on the base of the outside ceramic. Most were little more than finger tight. Several had cooked oil/exhaust residue on the threads which I cleaned up. The exhaust tick went entirely away for a week. Now it is back. Does anyone know a safe torque value to use that will prevent this loosening?

I just went out and checked torque and passenger side plugs. I would say the breakout force to loosen the plugs ranged from 3 to 8 ft lbs. I have always used the strong arm method of tightening plugs before this car. Never had a problem with stripped threads, difficult to remove, or loosening plugs. ( that is over 8 different landcruisers.. 1F, 2F, 3F and four 1fz engines, not to mention several honda and toyota sedans. Never a problem. I always tightened new plugs to where I could feel the crush ring settle... plus a little more.

I just re tightened the passenger side to 16 ft lbs and the exhaust tick is gone again. I forgot to mention I have been able to smell a little exhaust , and re-torquing the plugs the exhaust smell is gone.
I will wait for a while before I check the drivers side.

I wonder if this might be going on with me too.
On my way to work one day this week i had a strange smell, almost smelled like gear oil, but a quick check showed nothing.
Then after work when I got home walking past the front of the truck I smelled raw exhaust coming from the passenger side, popped the hood, smell lingered.
I do have an occasional exhaust tick but I figured it was the manifold leaking.
I will have to investigate further.

 

[FxFormat]

I did my plugs last week, and ALL of them were loose. I spun them out by hand without a ratchet, i just stuck a socket and an extension in there just to "seat" the onto the socket, and it just twisted right off! So yeah, check you plugs.

 

[2001LC]

Are the Denso's made in Japan or the USA? I've seen a lot of the Denso stuff manufactured in the USA lately. I usually stick to NGK.

All the Denso plugs I see these days are USA made. When I pull plugs from a 100 series for the first time, where made is big clue as to factory installed plug or replacements. Japanese or USA made is not making any difference in my findings.

I've been getting great deals at local parts stores on the Denso's USA. I've not checked to see, where the Toyota supplied one's are made. But unfortunately, to many parts store plugs. The gap is off. WHY, I can only speculate!

These days I but only from either Denso distributor (which sell NGK also) or Toyota. Gap always dead-on.

Great advice on checking the torque I have never really thought the plugs would back out on their own. Just curious, why do you recommend not changing the gap of used spark plugs? I realize it will change how it fires but wouldn't disconnecting the battery for 30min or so and then letting it idle after you have it all back together correct this?

Look back at the FSM picture on gap. Factory clearly states do not change gap of used. Why! Well I suppose it has to do with the annealing/heating of the metal. Once heated/used it's properties change.

^^^^^^^^ Agreed. While it is not impossible for the plugs to physically back off the threads, it would require poor contact with a coil 'boot' to do so. Good idea to replace the boots along with the spark plugs. Just about every one of mine had hardened from engine heat, last time I installed new plugs.

Not much that can be done about the sealing ring ....except to check your plugs from time to time.

**** BTW, judging by the color of your radiator 'top' you'll be needing a new one in the not too distant future.

I'll find some boots are still soft and pliable. While others are hard, cracking and discolored. The later is almost always, on the loose plugs. A second question becomes; has integrity of coil been compromised by heat from combustion gasses. I say this because heat is the killer of coils. When to replace Ignition coils.
Edited: 12/27/23 BTW: That radiator last another 60K miles. Until I replaced thermostats & radiator cap, being pressure back up to spec.

On #7 I used all my extensions and got my ratchet past the a/c lines.
That worked pretty well for me, just throwing that out there.
I also spray down into the spark plug hole with WD-40 or the like and let it soak for a few minutes before trying to remove the spark plugs.
You don't need much, just a quick squirt or two.

I think you mean cylinder #8 (RH rear) spark plug.

I'd suggest cleaning out tube before installing plugs if anything sprayed in them.

UPDATE BELOW; Last July, I replaced two 80s with an 04 LX470 with 110,000 on the clock. In my base lining I replaced the plugs with denso iridiums. I used the FSM torque value of 13 lbs/ft to tighten. I also used a little antisieze specified for spark plugs. Since then, I thought I had developed the header tick on the Passenger side. Last week at 124,000 on the clock, and with all the posts on self loosening plugs, I thought I would check that first. Sure enough, All plugs were in various stages of looseness. One on the PS had some corona burning on the base of the outside ceramic. Most were little more than finger tight. Several had cooked oil/exhaust residue on the threads which I cleaned up. The exhaust tick went entirely away for a week. Now it is back. Does anyone know a safe torque value to use that will prevent this loosening?

I just went out and checked torque and passenger side plugs. I would say the breakout force to loosen the plugs ranged from 3 to 8 ft lbs. I have always used the strong arm method of tightening plugs before this car. Never had a problem with stripped threads, difficult to remove, or loosening plugs. ( that is over 8 different landcruisers.. 1F, 2F, 3F and four 1fz engines, not to mention several honda and toyota sedans. Never a problem. I always tightened new plugs to where I could feel the crush ring settle... plus a little more.

I just re tightened the passenger side to 16 ft lbs and the exhaust tick is gone again. I forgot to mention I have been able to smell a little exhaust , and re-torquing the plugs the exhaust smell is gone.
I will wait for a while before I check the drivers side.

I have, once used a tiny dab of anti-sieze then wiped it off. This leave just a very thin film on threads. But I'm going to stop that practice. Your finding those loose so quickly reinforce not using any anti-seize. Toyota, in recommending these plugs, must have consider steel going into aluminum heads. So Denso & NGK surely have considered this in selection of metals used.

But it was pulling a factory installed set from The Black Knight, that convinced me we've and issue. Before that I was thinking guys just weren't torquing. But I was becoming concerned something was up. So I was really started paying attention. The factory installed would not have any lubricant on thread and would have been torqued to spec.

I've been considering going with a higher torque in the 16 to 18ft.lbf range. Overtime we'll hopefully get report back here if this makes any difference at all.

I wouldn't use never seize, but I understand why some would.

{{ title }} NGK website

Plug Torque Settings denso

I had looked at these a few months ago, when I first became aware of issue. It's gave me comfort we can use a higher torque. Just not sure it will help.

I have questioned myself of use of the anti seize. I think it comes from paranoia from when I have purchase a used car and have had to use so much force on my first plug removal, wondering if the threads, or plug would destruct. I have wondered if the anti seize is a factor, I have also wondered if I need to check the calibration on my torque wrenches. I have seen the damage a loose plug can cause and I hope someone out there can find a solution. 14,000 miles and finger tight plugs is downright un nerving.

That 14K miles statement has me concerned, my 30k 3 yr PM may be to long and interval. Edited 2023: I've found it's heating and cooling cycles more than miles, is the key. Where 30K mile recheck may be best for some, that drive very short distance daily. Most will be fine, just replacing ever 90K miles. Clue is listen for the tick/pop on cold start up. Sounds just like an exhaust header leak.

It will be this forum, that over time, will gives the best practice IMHO.

 

[jerryb]

you guys had me all paranoid. Mine were dealer replaced by PO @146k miles, I'm @194k today. So I never checked them or the coil packs for 18 months since purchase. I didn't find any loose or any sign of never seize on the five that I checked. They looked nice, coils looked nice, and the coil boots looked next to new. Thanks PO

They were definitely tighter than 15ft lbs.

Anyway, the reason I posted is that the spark plug socket in the toyota tool pouch is nice!