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Spark plugs stuck

Hey, all,
I tried to change the spark plugs on my mom’s 2001 Dodge Cavaran (3.3L V6 without flex fuel) as part of “regular” maintenance. I am not ASE certified or have any formal training in cars, but I do know my way around an engine well and can do most repairs and/or maintenance on my own. However, the spark plugs are stuck. I had a feeling this would happen, as my mom is terrible with maintenance and has her car with 181,000 miles with the original plugs in it. Needless to say, I blasted the plugs with WD-40, cleaned around the entry point to the cylinder head, and tried this many times all without even budging the plug. I don’t want to twist any harder with the ratchet because I really don’t feel like snapping the plug, but I just honestly don’t really see anything else I can do. Any suggestions, past experience, or help? Much appreciated in advance. Thanks!

Try using PB Blaster or SeaFoam, let it sit overnight. These can be found at any auto parts store. One product that often works when nothing else works is called Breakfree CLP. You can find it at most gun stores. which ever you use, let it soak overnight, then run the engine until it is hot and remove the plugs using a breaker bar and a good six point sparkplug socket.

If you only have a 3/8" drive spark plug socket, use the shortest extension you can get by with and a 1/2 to 3/8 adapter and a long 1/2" drive breaker bar. You will have more control over it with this.

The vehicle may now have what are called forever plugs.

When plugs are left in an engine that long, carbon can build up on the threads of the plugs that stick into the combustion chambers. This basically locks the plugs into their holes.

What you might want to try is decarbonizing of the engine with Seafoam.

Get the engine up to operating temperature and shut the engine off. Remove the brake booster vacuum hose from the brake booster and adapt a smaller hose that fits into the end of the brake booster hose and into the can of Seafoam. Take a pair of pliers and pinch off this hose.

Have someone start the engine and bring the idle speed to 2,000 RPM’s. Now slowly open the pliers so the Seafoam begins to be drawn into the engine. You’ll have to close and open the pliers during this to prevent the engine from stalling.

Once all the Seafoam has been drawn into the engine shut the engine off. Reconnect the brake booster vacuum hose. After a half hour has passed restart the engine and bring the speed back up to 2,000 RPM’s. Keep the RPM’s at 2,000 until the smoke clears from the exhaust and shut the engine off. Allow the engine to cool down and see if the plugs come out.


Wow, 13 years and 180k miles on those plugs…impressive. I’d love to see what they look like. Let us know if you succeed.

Man…I see the day coming when you may have to remove the cylinder head(s) just to replace the spark plugs. That’s after paying a machine shop to remove and replace them. @Tester…your comment sent shivers down my spine.

It used to be very common to see spark plugs protruding into the combustion chamber with exposed threads. Not saying it doesn’t still happen but with all the emphasis on reducing crevice volume (places for unburned hydrocarbons to hide), they are often flush with the inside surface now. I would still try the suggested decarbonizing treatment and pray for a miracle. But realize that there is still the potential for the plug to become corroded in place over time. You have galvanized steel body for the plug and aluminum for the head. While they are somewhat close in the galvanic series, they can and will eventually corrode to the point they are fused together and unable to be removed without damage. Platings, coatings, anti-sieze compounds only last so long…

Let penetrating lube soak in and then try an impact wrench. While it would be foolish to use and impact wrench on spark plugs in normal circumstances, the pulses might be enough to help loosen the plugs. If you don’t have one, and don’t wish to invest in a compressor, electric impact wrenches are available from some sources. They lack the power of a good air-driven unit, but they might be just the thing for this application.

If you manage to break them loose a little it would be a good idea to spray some PB Blaster down in there and allow it to soak a while.
After soaking try working any breakover with a back and forth motion. E.G. tighten a little, loosen a little, tighten, etc, etc until the plugs come out.
A mumbled prayer along the way might help; or not… :slight_smile:

If by chance the plugs come out without damaging the cylinder head threads it would be a good idea to use diaelectric grease on the plug boots and anti-seize on the threads of the new plugs.

Since ok4450 mentioned the prayer, I thought I’d help out if you need one:

I’d also add that, given the potential for the carbon issue, I’d be tempted to alternate my soak between PB Blaster-type product and a carb/throttle body cleaner-type product.

Hey, guys. Thanks for all the insight! I think I’ll soak them in PB Blaster today and work on it tomorrow. If that doesn’t work I’ll try the Seafoam idea that Tester suggested. I’ll keep you all posted.

There is an alternative to Testers method. You can buy SeaFoam in an aerosol can and just remove the duct from the throttle body, start the engine and spray into the throttle body. Might be a little easier.

Does anyone feel like there is too much risk to removal that maybe just leave it in “as permanent plugs” and let the thing be a problem when it decides to stop, vs purposely causing a problem now?

…and maybe change all of the other plugs that do come out easily and leave this one alone

@gdawgs, ALL the plugs are stuck.

The problem is that sooner or later there will problems from the plugs - and those problems can then go cause other expensive problems.

Are you now saying there is only one stuck? You said “this one.” Which bank is it on? Up front or back by the firewall? If its up front, its at least easier to work on if it breaks off.

If you can get 5 I’d be inclined to do those and keep soaking the last one (penetrating spray, then carb cleaner) over the next couple of weeks or so as she drives it. Then give it another whirl.

As an alternative to the impact, by the way, for certain things I prefer the “poor man’s impact” - which means whacking the end of the ratchet handle with a hammer. You keep a better feel for what kind of force is being visited on the plug.

As an alternative to the impact, by the way, for certain things I prefer the "poor man's impact" - which means whacking the end of the ratchet handle with a hammer.

I have to disagree on this one, you will damage the plug. I do have a system that works but you need the tools for this, if you don’t have them, you may not want to invest in them.

You need a sparkplug socket that has a hex head on it, most do anyway. Stick a 9 or 12" extension in it. Then use a wrench on the hex head to turn the socket while holding the extension to keep the socket properly aligned on the plug. You can use a hammer with this set up and you would be less likely to damage the plug because of the stability provided by the long extension.

Instead of using a hammer though, Id prefer a 16" or 24" breaker bar with a crows foot on the end to turn the socket while holding the extension to insure the socket is always aligned with the plug. You can sub a wrench with an Ozark engineered cheater bar (pipe) on it.

Of course you also need the room for the extension which you don’t often get with a sidewinder V6 engine, especially on the rear plugs. Any extension, even a 3" extension will help but the longer the better.

I think he’s just not getting enough leverage with a small ratchet.

Concur with the liquid wrench or pb blaster overnight soak and the importance of using a 6 point (rather than a 12 point) socket comments above. hmmm … An impact wrench would be a good idea to try, but it might be difficult to use one due to access problems. Whacking a breaker bar probably isn’t as good as an impact wrench at loosening stuck fasteners. The impact wrench would give a shorter and more firm impact effect than you’d get by hitting the end of a breaker bar, which would flex upon impact. But whacking with a hammer is better than nothing so is worth a try. There are reasonably priced electrical (and air driven) hammers available too, which sort of vibrate a nail into a piece of wood. Maybe something like that with the proper adapters might be worth a try.

What else? There’s an article on removing stuck fasteners (including spark plugs) in a recent issue of popular mechanics, I think it might have been just last month. One thing they suggested was to apply a tightening force first. They also mentioned when dealing with spark plugs, to be prepared to completely remove the plug once it begins to loosen, rather than stopping in midstream. Stopping may cause the plug to become impossible to remove without using a machine shop.

One bit of advice my dad told me as a teenager when working on cars is to remove as much stuff that is in the way as possible. For example, remove the battery, alternator, air filter box, filter box to intake manifold plenum, even the throttle body if that helps. It might even pay off time- & $$-wise to rent a engine crane and engine stand and completely remove the engine to give you optimum mechanical access to the spark plugs.

I agree with the others on the PB Blast.
The only good thing IMOO about WD 40 is the can is pretty. IMO it is worthless. I have a can and I don’t know why but I will keep it 40 years and get my money back from a picker.

edit, it makes a good flame thrower.

My air impact is rated at 525, and I wouldn’t want to put that anywhere near a plug (I mentioned this whole thing because mountainbike mentioned an impact). Even your wimpier impacts hit 200 or so and I wouldn’t want that on a plug either. I have no idea if mine actually does 525 ftlb, but I know I’m not getting there with a hammer.

The point about the hammer is that it is “gentler” and gives the user a better feel for the amount of power applied. But it still produces the shock/vibration that helps the penetrants make it down into the threads and can help break thing loose.

Before I owned an impact, I got many a stubborn fastener this way. The only way I’ve ever stripped a hex was with a breaker bar. I’ve broken a hex bolt with both impact and breaker bar. I also broke a 1/2" breaker bar once (well, I was jumping up and down on it - axle nut). But I never made any mess with a hammer and wrench or hammer and ratchet. I’ve also never had trouble keeping a spark plug socket on a plug. They contain the rubber sleeve that grips the plug and keeps the socket square and firmly on the hex.