Ticking time bomb TICK TICK TICK: Spark plugs Alert Alert Alert! (4 Viewers)

[Spike555]

So I went out and double checked my plugs, none were loose, still just as tight as when I put them in 2yrs ago.

My money is on people using the touqre specs, I touqre nothing, I tighten until I feel it's good and then call it good.

So someone who works on these things I think needs to over touqre, then recheck a few yrs later to compare to trucks that they used the factory touqre specs for the plugs and see which ones are coming loose.

 

[reznunt]

Thanks for the heads up, OP. Something to look for next time I go to replace them.

 

[abuck99]

Good discussion Paul. Thanks for alert-alert. ( reminded me of the robot on lost in space....”warning will robinson”...)

I dont know if this is best practice or not, but on new plugs I tighten to finger tight, then put a socket on it and go about another 1/4 turn to squish the new washer, then back it off and then torque to spec.

That takes care of working through the initial squish of a new plug washer.

 

[fooldall1]

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!

Never even noticed that!! Thanks!!

 

[Drogon]

Changed my plugs about 1k mi ago, and torqued to13lbs. This thread has gotten me curious. I will recheck them in 6months to see how they holding up.

I did have one brown tipped coil pack, and all the coil packs were extremely easy to pull out. Should they have a little suction to them when pulling out?

 

[apdxyk]

Thank you for the detailed follow ups.

Here are some more pictures of the boot damage

 

[2001LC]

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!

That's some good data points.

48K miles in 18 months would be ~32k miles a year. That ~3X national averager.

This would indicate minimal cool down cycles. Also we've no way to know what Dealer torqued to. Many use old school of snug then a quarter turn.

So I went out and double checked my plugs, none were loose, still just as tight as when I put them in 2yrs ago.

My money is on people using the touqre specs, I touqre nothing, I tighten until I feel it's good and then call it good.

So someone who works on these things I think needs to over touqre, then recheck a few yrs later to compare to trucks that they used the factory touqre specs for the plugs and see which ones are coming loose.

If by this "My money is on people using the torque specs" you mean those using factory spec will find them loosening. Well I suspect your right. Toyota is known for using very light torque specs. Looking at Denso torque chart it's apparent Toyota is light and we can safely use a higher torque!

Keep in mind: It wasn't until I did an 11 year old rig (TBK) with only 59K on the factory installed spark plugs that I became convinced to add this to my PMs The 30K mile or 3 years is something I pulled out of the hat, as a PM. History and carfax indicated TBK was driven regularly < than ~500 miles a month. That is a lot of cool downs cycles.

Lexus had 60K on Lexus.com as replacement PM, whereas Toyota had at 120K IIRC for EPA laws. Lexus may have just felt the labor justified replacing while in there. I say this because I've seen plugs with 120K miles still good, that gap was just a little over 1.1mm. They looked like they could go another 100K.

Thanks for the heads up, OP. Something to look for next time I go to replace them.

Good discussion Paul. Thanks for alert-alert. ( reminded me of the robot on lost in space....”warning will robinson”...)

I dont know if this is best practice or not, but on new plugs I tighten to finger tight, then put a socket on it and go about another 1/4 turn to squish the new washer, then back it off and then torque to spec.

That takes care of working through the initial squish of a new plug washer.

" Will Robinson"


Many shop use that 1/4 turn technique.

Typically we don't reuse crush washer. For that reason I've been going spec torque plus a little anytime I'm just cleaning, inspecting and reusing.

Thank you for the detailed follow ups.

Here are some more pictures of the boot damage

Thanks for those. How about posting your picture in this thread?

 

[jerryb]

Hey Paul, mine was dealer serviced @ 149, I purchased @171 today it's @194. Sorry I wasn't clear, I drive about 18-20k a year.

 

[2001LC]

Hey Paul, mine was dealer serviced @ 149, I purchased @171 today it's @194. Sorry I wasn't clear, I drive about 18-20k a year.

 

[white_lx]

Very timely. Thanks. I was about to change the factory plugs for the first time, now she is officially no longer a minor.

I've been getting great deals at local parts stores the Denso's USA, and have not checked to see if where the Toyota supplied are made.

Toyota ones are USA made.

Factory plugs

• white_lx
• Mar 5, 2018

 

[sean2202]

Thanks for the alert. Funny thing its on my list to check my plugs this spring I have 35k and about 2 years on since I installed.

I don't use a torque wrench to tighten plugs and I rarely use a torque wrench for torque specs were I work. Have you all checked your torque wrench calibration?

I would not reccomend using anti seize on your plugs especially if using a torque wrench. If you really want to get technical anti seize can change the resistance measured. I used to use anti seize (too much can cause cross threading and creates a paste when hardened) but now use a dab of used engine oil on plug threads. I was told this by an old time engine builder. I guess something with the carbon in the used engine oil.

Also there have been threads about wheel lug torque not being high enough and lugs loosenening up. I feel Toyota specs are on the low side on these two items.

 

[Spike555]

Thanks for the alert. Funny thing its on my list to check my plugs this spring I have 35k and about 2 years on since I installed.

I don't use a torque wrench to tighten plugs and I rarely use a torque wrench for torque specs were I work. Have you all checked your torque wrench calibration?

I would not reccomend using anti seize on your plugs especially if using a torque wrench. If you really want to get technical anti seize can change the resistance measured. I used to use anti seize (too much can cause cross threading and creates a paste when hardened) but now use a dab of used engine oil on plug threads. I was told this by an old time engine builder. I guess something with the carbon in the used engine oil.

Also there have been threads about wheel lug torque not being high enough and lugs loosenening up. I feel Toyota specs are on the low side on these two items.

Using a light oil on threads is fine for when using a torque wrench, the oil will squeeze out of the threads and not mess with the torque values.
Never never ever use anti sieze on lug nuts, light oil only, WD-40 works great as it evaporates. So any excess will not stick around.

My wifes van, spark plug replacement...when the check engine light comes on for random misfire codes. Then and only then do you mess with the spark plugs, says it right in the maintence book.
185k on the factory Iridium's and still running great.

 

[dace voit]

13ft/lb, while OEM spec, seems low. In my 1FZ I torqued to feel which was around 18-22 when I checked after. In my Audi UrS4 the spec is 22 ft/lb and I would torque to 25. Those cars were known to have plugs back out as well. I never use anti-seize on plug threads either. Only clean threads. I can understand why one would consider using it given a 100k plug change interval, but personally in 25+ years of wrenching(shade tree) I have never come across a plug that was seized for any other reason than cross-threading. That said, I don't advocate for serious over-torqueing of plugs. That's an YMMV situation

I dont know if this is best practice or not, but on new plugs I tighten to finger tight, then put a socket on it and go about another 1/4 turn to squish the new washer, then back it off and then torque to spec.

That takes care of working through the initial squish of a new plug washer.

I've read of others using this practice as well. It has worked for them from what I've read. I've not needed to try this as my over-torqueing seems to compensate.

 

[Superflo]

Good tip. I just got around to doing my plugs last week at 116k. #8 got stuck and would not come out but after shooting it with some penetrating lube and letting it sit for about 30 minutes it finally loosened.

I'll be checking them in 25k to see if they've loosened and maybe during oil changes if I'm not being rushed.

 

[KFunk740]

I normally use a torque wrench for about everything, but 13 lb-feet seems way low. I've got a lot of other vehicles, and around 21 to 25 is the usual spec (although my friends have made fun of me for using the torque wrench on plugs).

I haven't touched the plugs on my LC yet, but its on my list. I may just go for 'good and tight' blindly, as I do when I get sloppy on other plugs and its never been a problem.

 

[abuck99]

@2001LC - What is Denso’s torque spec?

 

[2001LC]

Good tip. I just got around to doing my plugs last week at 116k. #8 got stuck and would not come out but after shooting it with some penetrating lube and letting it sit for about 30 minutes it finally loosened.

I'll be checking them in 25k to see if they've loosened and maybe during oil changes if I'm not being rushed.

I avoid spraying penetrating oils in spark plug tube. It's probably not a big deal, but one of my concerns is accentuating heat transfer. Additionally next person to look down the tube may think the burnt off oil in bottom is a spark plug tube oil seal leak.

So for those occasion when I do use a penetrating oil, I wipe it out the best I can. To wipe out spark plug tube, I built a simple tool. It's a wire coat hanger with a lint free rag pitched in wire loop at one end.

I normally use a torque wrench for about everything, but 13 lb-feet seems way low. I've got a lot of other vehicles, and around 21 to 25 is the usual spec (although my friends have made fun of me for using the torque wrench on plugs).

I haven't touched the plugs on my LC yet, but its on my list. I may just go for 'good and tight' blindly, as I do when I get sloppy on other plugs and its never been a problem.

I ussal use a torque wrench on ever bolt & nut, I can find a spec for.

But to be clear, the four inner plugs I've been finding loose consistently, I've no idea of what method was used to tighten them. The one exception, were the loose factory installed (torqued) in The Black Knight.

I do think but don't know, increasing torque will help. The only way we'll know is by those torque to specific higher torque and report back here years from now.

One thing more to consider doing this as a 30K mile or 3 year PM. It's not a bad idea to clean and inspect plugs anyway.

 

[2001LC]

@2001LC - What is Denso’s torque spec?

Sorry I thought it was here, which is good to read also Plug Torque Settings

Here is the actual Denso link Spark Plug Installation

15 to 22ft-lbf.

Reading both links, you'll see lubing threads or reusing plug (washer is crushed) changes recommendation.

 

[abuck99]

Sorry I thought it was here, which is good to read also Plug Torque Settings

Here is the actual Denso link Spark Plug Installation

15 to 22ft-lbf.

Reading both links, you'll see lubing threads or reusing plug (washer is crushed) changes recommendation.

Perfect- thanks!

 

[white_lx]

Here is another data point: Just replaced the original plugs in our '00 LX470 with 81k miles. All plugs were tight, without being too difficult to remove. No sign of leakage.

Torqued the new plugs to 14 ft.lbf, just to make sure. I did notice that there was quite a bit of creep. When I re-tightened the plugs after about one hour, some of them were turning another 20-30 degrees with the same torque setting. All of them turned at least a little. Waited a bit more and third time there was very little additional turning. Engine was cold and I was using a quality (Norbar) torque wrench, in case there is questions abut the torque wrench.