Spark Plug Removal, dodged the bullet....! (1 Viewer)

[flintknapper]

I have been base-lining a 'new to me' 99 LX470. Very clean for the year model and mileage, pretty good service history.

Went to change out the spark plugs a couple of days ago and got quite the 'scare'.

All plugs in the passenger side bank cylinders (2,4,6,8) came out easily (almost too easy).

But when I went to the other side (cylinders 1,3,5,7) all were tight and # 3 was REAL tight!

Over a period of 24 hrs. I managed to slowly back out the plugs 1,5 & 7 by soaking the S/P tube with PB Blaster, letting it sit and then getting maybe a quarter turn on the plug. Let sit for a while... then try again.

But the #3 cylinder was clearly going to be a challenge. I just knew a heli-coil was going to be in my future for that cylinder.

It's not good when you can only turn the plug about 1/8th round before it really 'loads up'. Even had it 'chatter' a couple of times. 2 days later (moving it a small bit and keeping it soaked) I finally got to a point where I could get 1/2 turns with just a good constant pressure.

I suppose everyone has a different technique, but some accounts I have read suggested turning the spark plug out until it binds then turn it BACK a small amount. I disagree with this strongly (turning it back).

Each time I would try to turn the plug back it would immediately try to 'seize'. You should not underestimate the heat build up created by the friction involved. Once you gall the threads in the head...its a done deal and nothing good is going to happen after that.

Take it slowly, let the penetrating oil work. Don't expect to get much movement out a plug as 'stuck' as mine were. By not 'forcing' it I was able to get all the plugs out without damage to the head.

When installing your new plugs....do NOT over-tighten them. There is some controversy as to whether or not using an 'anti-seize' product on the plug threads is helpful. I did on mine. Went back with a light coat of Copper Anti-Seize.

So glad I didn't ruin a cylinder head, it was nip and tuck for awhile.

Flint.

 

[Mike6158]

I hope I never need this info but I'm glad that you posted this

 

[cwmoser]

Good information for us DIYers. Thanks for sharing.

 

[brianrride]

Good work and even better patience!

 

[cwmoser]

BTW, what is the Torque we should use to tighten Spark Plugs?

 

[LEX]

I'm doing mine soon and now picking up a can of PB Blaster just in case.

 

[RND1]

Thanks for sharing your experience - how many miles on your LX and were the plugs original? I'm at 115K miles on original plugs so it's on my list for the next service.

 

[2001LC]

BTW, what is the Torque we should use to tighten Spark Plugs?

13ft lbf

 

[sean2202]

Way to have patients...bravo!!! you saved some money and frustration. I have used a dab of anti seize on plugs in the past. The one thing that you have to remember with this is that anti seize on threads can change the amount of torque needed on a plug and too much can cause issues such as fouling and stripping the threads. Recently an engine builder told me to use "used motor oil" on spark plug threads. Something about the carbon in it.
For those really stuck bolts use Kano Kroil penetrating oil. Expensive but works better than p-b blaster. I have seen this used on those notorious ford plugs in the 5.4 with good results and patients as well.

 

[Mike6158]

Another vote for Kano Kroil. That stuff is amazing.

 

[flintknapper]

Thanks for sharing your experience - how many miles on your LX and were the plugs original? I'm at 115K miles on original plugs so it's on my list for the next service.

186K on the LX. My best guess is the plugs are the originals, judging by the appearance and erosion of the electrodes.

Before purchasing the vehicle I obtained a CarFax report (pretty much worthless) but also service history reports from 'Lexus Drivers'. The L/D reports (while not always detailed) showed so much more than the CarFax.

This vehicle missed it's 90K scheduled service (timing belt, spark plugs, ect) so I doubt they had ever been changed. The timing belt and pulleys/tensioner was done at 156K when one of the pulleys seized and shredded the belt (resulting in a no start condition). All of that is documented.

As for 'torque' figures on the spark plug....it is a good 'guideline' but personally....I will rely on 'feel'. The reason being...each thread bore is going to be a little different in terms of its condition when you remove the plug from it. Some amount of residue (carbon from plug, and galvanic corrosion). Since the plugs use a flat washer to create a 'seal', I just run them down until I can feel the 'crush' and then stop.

 

[Slickspawn]

Did you start the job with the engine hot or warm?

 

[2001LC]

186K on the LX. My best guess is the plugs are the originals, judging by the appearance and erosion of the electrodes.

*******
As for 'torque' figures on the spark plug....it is a good 'guideline' but personally....I will rely on 'feel'. The reason being...each thread bore is going to be a little different in terms of its condition when you remove the plug from it. Some amount of residue (carbon from plug, and galvanic corrosion). Since the plugs use a flat washer to create a 'seal', I just run them down until I can feel the 'crush' and then stop.

I think feel is what PO's repair shop used. I found two finger tight, three over tighten and three maybe just right!

 

[flintknapper]

Did you start the job with the engine hot or warm?

No, dead cold. Had the intake off replacing the starter.

I know where you are going with this, some maintain (and I agree) that plugs 'can' be easier to remove when the heads are warm.

I don't disagree with that...but in my case there was more going on than just cool cylinder heads.