Seized spark plugs

[Kamalea]

Need help in releasing seized spark plugs in my 86, 930 Turbo.
The engine is in the car with limited working space.
Is it safe to apply Liquid wrench or similar products to help releasing them?
Many thanks in advance

[Lyle O]

Should be no problem, if you stick with the good, name brand stuff. Just wipe it down well when you free them up (stick a swab of some sort down the tubes). The common penetrating oils have pretty low flash point compared to regular oils, and what little residuals that are there will get burned off if they make it into the cylinder. Just be sure NOT to use anything with silicone or graphite in it. Good luck.

[CCM911]

I know this may sound dumb, but would they budge if you ran the engine a bit to build up some heat?

[ArchHibb]

By "seized" do you mean they won't break loose or do you mean they started to turn and then seized or bound up?

If the former, hit them with PB Blaster every day for a week. That worked to free my rusty frozen O2 sensor, so it should work for plugs.

If the latter, it's most likely carbon deposits on the very ends of the plug threads that are jamming in the head threads. No Liquid Wrench or PB is going to clear that. Carefully work each plug back and forth to chase the deposits out. Be patient, go slow, and spray either of those products to help lubricate the process.

[911pcars]

If the engine runs, I would also suggest bringing it to operating temperature after applying penetrating oil. The aluminum head (and spark plug hole) should expand at a greater rate than the steel spark plug.

In tests, Liquid Wrench is okay, but there are better products e.g. Kroil, ATF + acetone, etc.).

Porsche says not to use anti-seize on spark plug threads. I say nein. Apply it very sparingly to the threads and this shouldn't happen anymore.

Sherwood

[gamin]

+1 on using anti-seize on the plug threads. I've been doing that on Porsche's for 46 years and never a problem.

[911pcars]

Originally Posted by ArchHibb

By "seized" do you mean they won't break loose or do you mean they started to turn and then seized or bound up?

If the former, hit them with PB Blaster every day for a week. That worked to free my rusty frozen O2 sensor, so it should work for plugs.

If the latter, it's most likely carbon deposits on the very ends of the plug threads that are jamming in the head threads. No Liquid Wrench or PB is going to clear that. Carefully work each plug back and forth to chase the deposits out. Be patient, go slow, and spray either of those products to help lubricate the process.

Spark plug threads shouldn't be exposed. However, carbon buildup could make it more difficult to back out the plug. In this case, try "steam cleaning" the combustion chambers with a fine spray of water into the intake at high idle. Disregard the temporary neighborhood smoke coverage, but after a bit, the steam will have scoured the chamber of all carbon. Use in conjunction with a bit of Marvel Mystery oil in the fuel tank. Acts like an upper cylinder lube to help soften combustion byproducts and lube moving parts.

Resist the urge to apply brute force.

Sherwood

[p911dad]

+ 1 on Kroil. My mechanic couldn't get #3 and #6 out so I fiddled with it for a week or so giving it little daily shots of Kroil, one day they busted loose. Very slowly turn counter-clockwise a little and then turn back in a little, ease them out. It was a "crap your pants" moment, when I thought I might have stripped them, but no aluminum on the threads! Some say a little tap in the end of the plug can help too.

[E Sully]

Since aluminum expands more than steel, warm engine might make it easier.

Originally Posted by gamin

+1 on using anti-seize on the plug threads. I've been doing that on Porsche's for 46 years and never a problem.

This is OK when reinstalling spark plugs, but should not be done on new spark plugs. All manufacturers state that anti sieze is pre done on new plug threads and not to add anything, but when putting used plugs back in and using compound, reduce from original torque used.

[Bob Kontak]

[QUOTE=E Sully;8159220]Since aluminum expands more than steel, warm engine might make it easier.[/QUOTE"

Absolutely +1.

Ed, do you own a ford truck? That's the secret with them Warm block, crack the plugs 1/4-1/8 turn, spray PB Blaster (or equivelent) and a shot of carb cleaner to speed the penetration. Give it 20 minutes before removing.

Problem is with the mid 00's Fords, the tip of the plug extends into the cylinder and the extension cakes with carbon. Bore too small to back plug out. Heat and soften.

[TCracingCA]

Yes aluminum will expand and seize the plug also harder than it is! ""Thus"" why do people think that the aluminum head is going to expand with heat everywhere except where it holds the spark plug threaded in???? OH Boy! ????? First so you don't make any mistakes and wipe out the threads, but it could happen anyways. Put a torque wrench set at about 1/2 of the spark plug torque and after using some penetrating oils or I have used a spritz of kerosene which can act as a cleaner, lubricant, etc. soak on oxidized parts etc.. then hit it will the torque wrench in the opposite direction. If no go, spray more stuff and let sit! Then reset the torque wrench but no higher than about a couple of pounds below the recommended torque and try to back it out. You might try torqueing it also in the normal in direction which on occasion will free it turning it in and not out, which is another trick! It is hard to get penetrating oils down locked threads, so that could take time. And as others said, if it was just some carbon, torqueing in and out a few times normally breaks that, rare that it would seem heavily stuck because of carbon! If you took the torque up one pound over normal torque, and gave it a nudge inward, then you would get a hair of movement to tell you it is carbon holding it up, But It would really need to be bonded on to carbon stick a plug in my opinion. It was the lack of an anti-seize more than likely as the cause!

[Tidybuoy]

Originally Posted by 911pcars

In tests, Liquid Wrench is okay, but there are better products e.g. Kroil, ATF + acetone, etc.).
Sherwood

+1 on the ATF + Acetone (50/50 mix). I used this on my fuel distributor piston and after just a few minutes it unfroze. This was after two weeks of no success with all the other products. It's really a miracle worker.

[TCracingCA]

But if the plugs were torqued in, then it is going to take the entire torque setting to get them back out at least and hopefully not more. I hate to put more force on it than torque plus 1 pound to get them back out. The 1/2 setting attempt is just so you know where you are at with your force, and maybe you will get lucky, but the torque wrench should snap! The close to torque is the same and we are trying to attempt to apply less than the normal torque if lucky to get it started out! But if no go, then go torque plus one and try! Then after that, you would be putting more torque on it than should be normally needed or recommended and darn! It could be a reality that you have to apply more. Since it sounds like you can't get any of them out, the same problem is causing the problem, so that wouldn't be carbon for each and every one of them. The carbon on a plug would vary in one engine cylinder to cylinder some but enough that some in that case would have screwed out! If you put solvents on it, and they same to soak in, then that is hopeful. Then keep trying it at torque plus one or if someone gorilla-ed them in, then you might just have to go for it and get a rachet what the hell! Etc. I will spend alot of time on something like this, so as to not just strip out the threads and cause more problems.

[911pcars]

Breakaway torque is always higher than the initial applied torque. However, I understand the need to not overdo the rotational torque which could tear the aluminum threads from the cyl. head.

Still, the best method to minimize damage seems to be to take advantage of the different coefficient of expansion of the two materials in order to create a path for penetrating oil between the two parts.

As for what happens to the ID in a piece of metal when heated. Does it contract or expand?
It expands, as in heating a metal lid with hot water to unscrew it from a jar. And conversely, when reducing its temperature, it contracts.

To brain storm; if one were able to apply e.g. dry ice/freon/liquid nitrogen primarily to the spark plug it would rapidly lower its temperature relative to the surrounding metal and perhaps maybe shrink it just enough.

Sherwood

[E Sully]

Originally Posted by E Sully

Since aluminum expands more than steel, warm engine might make it easier.[/QUOTE"

Absolutely +1.

Ed, do you own a ford truck? That's the secret with them Warm block, crack the plugs 1/4-1/8 turn, spray PB Blaster (or equivelent) and a shot of carb cleaner to speed the penetration. Give it 20 minutes before removing.

Problem is with the mid 00's Fords, the tip of the plug extends into the cylinder and the extension cakes with carbon. Bore too small to back plug out. Heat and soften.

Yes Bob, like all my vehicles, had my truck till the frame rotted out from under it.

Originally Posted by TCracingCA

Yes aluminum will expand and seize the plug also harder than it is! ""Thus"" why do people think that the aluminum head is going to expand with heat everywhere except where it holds the spark plug threaded in???? OH Boy! ????? First so you don't make any mistakes and wipe out the threads, but it could happen anyways. It was the lack of an anti-seize more than likely as the cause!

I have pulled a lot of spark plugs from hot engines to read plugs for a/f mixture, leak down and compression checks. I have never stripped a plug.
As for the anti seize, I have been to spark plug manufacturers web sites and spark plug manufacturers coat the threads on new spark plugs and specify to not add any anti seize. They have found that anti seize will lead to over tightening. If re installing plugs some may want to use anti seize, but I never have, and have never had a spark plug strip threads when removing. I would say most problems with stripped plugs comes from cross threading when installed, and over torquing. If it's already stripped, no procedure will help, just have to fix it.

[TCracingCA]

A running operating engine, where it is getting regular service, should be no problem taking plugs in and out without problem and stripping and even hot or even if they were treated or not treated! Don't Know what we have here yet with this problem, the history or whether a gorilla torque was applied, the plugs haven't been out for so long that they are corroded in. Yes usually you need break away level of torque to loosen, and the ideal would be torque plus 1 pounds ideally or it should be a discipline to exercise, or if it takes more, then it would indicate that they are starting to bond themselves within the head for some reason. For all we know is why I suggested (and it is only a suggestion) is that if this was a stored engine with plugs installed, they could have been hand tightened in for storage and maybe a 1/2 torque might take them out. Since it is bonded or stuck or frozen and I am not the guy manipulating this wrench, I have no judgment of the actual force except as is being described and the guy could get a judgment as to the level of force being applied. Thus you could just step up the torque wrench until you have the pressure to turn them. And if the threads are all compromised from corrosion, then all of the carefullness in the world might not save them anyways! I have alot of aluminum stuff in my garage and I employ a torque wrench to also loosen things is something that I personally chose to do just because I am working with aluminum. Because I am not turning the wrench or knowing the condition or state of this engine, being overly cautious on my approach to giving a solution.

I have seen both negative and positive conversations on anti-seize compounds or oils and torque etc.. The anti-Seize could also be why the plugs are stuck! They were overtorqued do to it, and then heat and such burned that off, and now stuck!

Ps the ideal is not to be unscrewing things from aluminum when the aluminum is hot even if you have had success and no apparent problems. Thus if you have never lost any thread or experienced a problem, then you probably have a good sense for wrenching pressures and control.

I see that we are taking a very simple topic of some stuck spark plugs into a mega thread. Yes and I am at fault to! This should not be that hard and actually for most mechanics should not even warrant any type of discussion! Most of us good wrenches would just handle the problem!

[Bob Kontak]

[QUOTE=TCracingCA;8159475]Yes aluminum will expand and seize the plug also harder than it is![/QUOTE

Are you ABSOLUTELY sure of this? Not arguing, but this is a good data point to nail down for certain.

The below thread (post #1) says Waynes book states to change the plugs stone cold. Not convinced either way as to what would be the impact on the hole diameter when heated.

Offsetting the above a bit, in addition to what Ed said about reading plugs, it's common practice - not just an Ed thing - to shut the car down at speed, pull over and pull a plug(s) for a reading. Of course, the assumption is you don't have seized plugs.

Stuck spark plugs - good news

[TCracingCA]

I am actually trying to not argue about anything either!

I think the heat of the head or aluminum expansion etc. can affect torque also! I just think without changing any of the dynamics of the head with any condition, it is just better to put them in and take them out with torque dead cold!

Thus if you put them in hot, you probably reached torque earlier and then when cold it is easier to take them back out or they can be removed when hot again! Thus I would suspect that torque recommendations would have been made on parts when things weren't hot!

If that makes sense!

[Bob Kontak]

Originally Posted by Bob Kontak

Are you ABSOLUTELY sure of this? Not arguing, but this is a good data point to nail down for certain.

Did some sniffing and it's a mixed bag with over 50% saying NO, especially in a HOT engine.

One post I found outside of pelican indicated that the expansion rates does make the hole fatter than the plug but the pitch of the threads change between the two keeping the interference fit intact.

The seemingly knowledgeable folks say the secret is to create some form of movement between the two, then soak. Put some back and forth torque on the threads as TRacing says, Warm the engine slightly, freeze the plug, whack the plug when cold, then soak and walk away for a day.

Locktite makes a freeze spray for this and it has a penetrant.

Freeze Your Nuts Off | Toolmonger

[Bob Kontak]

Originally Posted by TCracingCA

II would suspect that torque recommendations would have been made on parts when things weren't hot!

If that makes sense!

I'll tell you what caught my eye is when you asked what if the plugs were over-torqued. Crud and corrosion fall out of the equation and interference becomes issue.

I do like the freezing the plug option to shrink before the final reef is applied - and that is the day after you perform procedures to get some penetrant in there.