I used PB blaster in the past and let it sit for a couple of hours. Another thing I have done for non spark plugs is get a blow torch and heat up the bolt/nut

 

Just curious, would it be better to try and remove them when the engine is hot or cold? I would guess hot?

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Just curious, would it be better to try and remove them when the engine is hot or cold? I would guess hot?

It seems like a good idea. The coefficient of thermal expansion is much higher in aluminum than in steel. The spark plug hole will expand radially more than the spark plug which may loosen it, however the length of the aluminum thread will elongate more with heat than the spark plug thread which may cause more thread binding. If they won't come out cold, it is worth trying to do hot just because it is different and might succeed as long as the same level of care to not damage the cylinder head is used.

I don't think that the crush washer on the spark plug would let penetrating oil pass to the threads and it would require cleaning up real well after to avoid leaving oil on the threads that could lead to overtightening the new spark plug when setting the installation torque.

 

I had to use a 2ft pipe to break all 3 on the driverside loose last time I did mine.. no more anti-seize and no more forearm torquing

 

I was once shown an old school trick to remove seized bolts. Set the ratchet to remove the plug and apply a Small amount of pressure. Change the direction of the ratchet (Tightening) and apply a Small amount of pressure. Repeat this process many many times and hopefully the plug will free up.

 

I saw this just before I had to remove 12 22-year old exhaust manifold bolts on my diesel RV. Before starting, I sprayed liberally with CRC Freeze Off and warmed the engine - several times over several days. Then I did what he says. Worked beautifully for me.

 

Great video, I would take a small wire brush and clean the bolt threads before / during backing it in / out when you can. THX oldMattB

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And I would have proceeded to continue with that spray along with that wire brush..

 

As alongapo2 said ... apply torque in both directions ... loosening direction then tightening direction to free-up the threads ... and once the plug let's go, continue to do the same (back-and -forth) until completely removed. This will minimize any thread damage. Using a huge breaker bar is asking to shear the plug off in the head ... then you are in for a big adventure. This post is proof that replacing the plugs every 50,000 miles is prudent ... for all reasons.

 

Hi,
I agreed on the PB blaster or just penetrating oil to soak on the threads for a day or two. Maybe try tightening by 1/8 or 1/4 turn but be careful, it’s aluminum. Also the hot/cold might do it too. Heat the engine and try spraying the top of the spark plug with compressed air in a can. When sprayed it gets very cold and might shrink it enough to help break the corrosion lose. Good luck and keep us posted.
Fort

 

Your probability of success depends heavily on what was done at the dealership before the mechanic gave up.

If the brute force method was used and the plugs were tight at first, but started to turn slightly and then got progressively tighter as the threads started to gall and seize, then you have a real challenge.

If the mechanic applied what would normally be adequate removal torque, but the plugs didn't budge, hopefully he took the conservative approach and rather than risk catastrophic damage via the 'apply more force' method, just stopped and noted that the plugs were 'seized'. If this is what happened, you're probably better off.

The repeated CW/CCW torque approach is likely your only lower-risk initial option.

If you can get the plugs rotated 1/4 - 1/2 turn, you may be able to 'unseal' the crush washer, and then flood the plug well with PB Blaster or similar penetrating lubricant and let it sit overnight if not longer. Once you get a little lubricant started into the top threads, repeatedly using the alternating LH/RH rotation + lubricant soak approach will tend to slowly work lubricant deeper into the threads.

I have also used a mixture of acetone (very low viscosity and great penetrating ability) and a small amount of very light oil as an initial penetrating lube, probably better than the commercial penetrating lubricants, but it evaporates rapidly. This isn't so much of an issue in a spark plug well where you can put something over the open end to seal it while soaking.

The FJ spark plug thread pitch is 1.25mm (about 0.05" per turn), so getting it unscrewed 1/4 turn will move the plug about 0.012", which (depending on the resilience of the crush washer) may be enough to allow your lubricant to seep past the washer and reach the threads.

Let us know what the final outcome is.

 

... hmmm ... how does a wire brush access the spark plug threads inside a spark plug well in the head ????

 

It doesn't, I was commenting on the video.

REEL-M-N said:
Great video, I would take a small wire brush and clean the bolt threads before / during backing it in / out when you can. THX oldMattB

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OK

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