decided to replace the spark plugs on my 4.2 trailblazer...appears easy enough...but I cannot get the old ones to budge. Using a 3/8" driver, I pulled fairly hard, though not as hard as I could for fear of stripping something. Is there a trick I can use to get them out without damaging anything? Can I spray some PBblaster in there without screwing something up?
stuck spark plugs
- Thread starter sunliner
- Start date
Einst-Hawk
Member
- Jan 31, 2014
- 105
My main advise would be to keep your extension and socket as straight as possible. Any amount of sway to either side of the hole could possibly crack the plug and I know you don't want that.
As long as PB Blaster is flammable, I don't see how it could hurt.
As long as PB Blaster is flammable, I don't see how it could hurt.
Rubber mallet can help, put ratcheteting/extension against palm and smack handle of ratchet with mallet counterclockwise. Can sometimes help break the corrosion/bonding.
I was tempted to do that...aluminum engine blocks scare me though. I'm no muscle man but I worry about pulling the threads.coolasice said:
http://gmtnation.com/forums/topic/11496-what-is-your-favorite-penetrating-oil/?hl=acetone#entry287608
Acetone and ATF is my goto nut buster since that thread.
Replaced the original rusted out exhaust headers on my brother's 1997 taurus last fall. I could not get the nuts to break free. Lil acetone and ATF and they broke free much easier than i thought.
I would take some in a turkey baster or similar and just put a few drops down the spark plug hole and let sit for fifteen minutes.
Acetone and ATF is my goto nut buster since that thread.
Replaced the original rusted out exhaust headers on my brother's 1997 taurus last fall. I could not get the nuts to break free. Lil acetone and ATF and they broke free much easier than i thought.
I would take some in a turkey baster or similar and just put a few drops down the spark plug hole and let sit for fifteen minutes.
Einst-Hawk
Member
- Jan 31, 2014
- 105
Do you have a cheater bar to put on the end of your ratchet to get more torque? I haven't heard of a case of stripping threads on the head (although I haven't worked on every car in existence) Breaking the plug is far more likely.
When you replace them, make sure you torque to only 156in/lbs. You would be surprised how little force that that is.
When you replace them, make sure you torque to only 156in/lbs. You would be surprised how little force that that is.
marinegrunt
Member
- Oct 13, 2012
- 110
I'm with Einst-Hawk on this one. Although not on our Envoy, I've had a couple break over the years, but have never had one strip out or have heard of it happening. If the threads do strip out they do have helicoils although I realize they might not be ideal for a head. You would have to worry about metal shavings from drilling it out though. I've read of people shoving a rope coated in grease down the plug hole first, drilling, and then pulling the rope out with needle nosed. I would think it would be easier to rig a small hose up to a shop vac though. If it were mine, and it stripped out, I'd probably pull the head to do it. If you left the head on there's really no way of knowing if you got all of the metal out and you don't want to score up the cylinder walls.
One thing that might help is by making sure the engine is hot. Aluminum expands at a lower temp than steel so it's worth trying if you haven't already. If push comes to shove you could probably even drain some of the antifreeze to get it a little hotter but you'd have to keep a very close eye on the engine temp. I would use a scan tool with live data and wouldn't push it or else you're asking for trouble. I almost didn't mention trying it because of the risk of getting it too hot.
If anything just take it to a shop and let them worry about it. Also be sure to use anti seize when installing new plugs. After I had my first one break I've always used anti seize on aluminum heads.
One thing that might help is by making sure the engine is hot. Aluminum expands at a lower temp than steel so it's worth trying if you haven't already. If push comes to shove you could probably even drain some of the antifreeze to get it a little hotter but you'd have to keep a very close eye on the engine temp. I would use a scan tool with live data and wouldn't push it or else you're asking for trouble. I almost didn't mention trying it because of the risk of getting it too hot.
If anything just take it to a shop and let them worry about it. Also be sure to use anti seize when installing new plugs. After I had my first one break I've always used anti seize on aluminum heads.
Mounce
Member
Isn't it molded into to the valve cover to never take them out while the motor is hot?
I know it says something..I just didn't bother to read the whole thing.
But +1 on antiseize on installation of new plugs.
I know it says something..I just didn't bother to read the whole thing.
But +1 on antiseize on installation of new plugs.
marinegrunt
Member
- Oct 13, 2012
- 110
I've never really paid enough attention to know if it says that but very well could. I wonder what the reason is behind it? Maybe more of a chance of stripping out the threads? Maybe a warning because some idiot sued after burning his hand?
It wouldn't surprise me if the reason really is to prevent someone from burning their hand. I know it's always best to follow manufacturer recommendations but I don't see how it could hurt anything. Don't take my word on it though because I really have no idea. Maybe only go this route as a last resort.
Mounce
Member
You "really have no idea" yet you're telling someone to drain coolant in order to make the engine even hotter...?
Sunliner, have you seen MAY's video? Maybe he said some tips or maybe it'll reassure you on the job. Good luck.
http://youtu.be/hB95ERNaUUk
Sunliner, have you seen MAY's video? Maybe he said some tips or maybe it'll reassure you on the job. Good luck.
http://youtu.be/hB95ERNaUUk
From the service manual: "Notice: Allow the engine to cool before removing the spark plugs. Attempting to remove the spark plugs from a hot engine may cause the plug threads to seize, causing damage to cylinder head threads."marinegrunt said:I've never really paid enough attention to know if it says that but very well could. I wonder what the reason is behind it? Maybe more of a chance of stripping out the threads? Maybe a warning because some idiot sued after burning his hand?
Mounce
Member
May03LT's videos are awesome and have saved my a$$ a few times. his spark plug change was pretty uneventful though. possibly because he's smart enough to not wait until 110,000 on the odometer to do his.
Mounce said:
Mounce
Member
Mounce
Member
Yeah, had not been driven for almost 24 hours. I have heard some say that maybe engine should be slightly warm for removal, but wait till it's stone-cold again to try to install new plugs, to avoid damage. I don't know for sure. It's just # 1,2 & 4 giving me grief, the others will come out.Mounce said:
Blckshdw
Moderator
I helped a buddy of mine change the plugs in his mom's 04 EXT that was about 60K miles overdue. A few of the plugs didn't want to play nice and he got worried about breaking them, but we kept at it with steady pressure and they eventually gave and came out. The engine was still warm when we did it, we let it sit for about 2 hours after he drove to my house. 
Eric04
Member
I've only ever broken one plug and it's not something fun to deal with. I have to assume the plugs in mine are the original set due to the mileage but if that's the case I feel as though I should change them soon because they've been in there for ten years. And yes, I'll be doing it cautiously when I do. Lol
Went at it again tonight. Tried it with engine warm. ..about three hours after last drive. Using a 3/8" driver (7" from ratchet axis to handle) even after soaking for about four hours in pb blaster, I can pull the damn driver pretty hard and this thing will not budge. I could pull harder and/or put a cheater bar on it but I think it should have loosened by now. The other three came out with far less effort. I'm not prepared to repair threads.
marinegrunt
Member
- Oct 13, 2012
- 110
I'm not trying to start a pissing match but you took two different sentences from two different posts to make it sound the way you wanted it to sound. The "no idea" came after someone mentioned about the warning under the hood and I was mentioning maybe why it was there but admitted to not knowing why. Most people know that aluminum expands at a lower temp than steel so seems like a plausible idea that would probably work even at normal operating temps. I mentioned getting it hotter before anyone mentioned that the warning was there. I even said if push comes to shove, monitor with a scan tool, and that I almost didn't mentioned because if you weren't careful you're asking for trouble. All of that is a lot different than what you decided to combine.Mounce said:
I was just throwing some ideas out there. I'd personally rather get everyone's ideas no matter how off the wall they are and decide on my own on how I want to approach it. After someone mentioned the warning I then said to only heat the engine as a last resort. I even mentioned about taking to a shop. Most can decide on their own when they're out of their comfort zone. I'm sure you've ran into problems before where you had to veer off the manufacturer recommendations. I'd rather take the chance of heating the engine than breaking a plug if they're that hard to get out. I've done it before on other vehicles and have never had the threads strip out because of it. They also warn about only using a certain type of specialty tool for certain jobs to prevent damage but there are ways around that. My Sierra has aluminum heads and there's no warning about only replacing plugs when engine is cool. It might be in the owner's manual though.
Call me stubborn or cheap but I've never taken a vehicle to a shop so sometimes I have to push the envelope because things don't always go as planned. Sometimes it bites you but sometimes nothing else will work. I left it up to the op on how far he wanted to push it. You've been here a long time so just let me know if you only want me posting what the manufacturer recommends.
Sparky
Member
- Dec 4, 2011
- 12,927
When pulling on the ratchet you are supporting the extension with the other hand to keep it straight right? I've noticed that if you just pull on the one end of a wrench when using an extension, without supporting it, that the resulting angled forces not only risk damage but it reduces effectiveness as the force is no longer applied in just one axis, so you pull harder for less effect.sunliner said:
You could try the old spray it daily trick for a few days so it goes through several heat cycles with fresh PB to let it work into the threads. Did that on my manifold to Y pipe bolts on my old car, the ones I could spray came off OK and the ones I couldn't get to broke off and I had to drill them out.
Blckshdw
Moderator
Sparky said:
When my friend's plugs were stuck and he didn't want to try anymore, I made sure to put my offhand on the ratchet head to hold it in place while cranking away on the handle. Using steady pressure, they eventually gave way.
marinegrunt
Member
- Oct 13, 2012
- 110
Yeah, it's never fun fixing threads especially spark plug threads. Just the idea of not knowing whether or not you got all of the shavings out is enough to drive you crazy. I feel for you because there's nothing worse than dealing with a stuck spark plug. When I was younger I had an old car where it happened. On that one I put the helicoil in with head in place. I also had one break on a Chevy Blazer. It was a much nicer vehicle, and the wife's ride, so I pulled the head for that one. It was newer so I didn't want to take any chances.
I think Sparky has the best and safest ideas here if you don't want to take it in.
I know some Ford trucks are known for having issues when removing spark plugs. Some use a battery operated impact to loosen them up. There shouldn't be enough torque to break them off and the vibrating action helps break them loose. I'd still be careful that way though. I have a 20v Dewalt impact driver. It's small but that thing has some decent power. As you know, regardless on how you try and get a stuck one out, there's always the risk of breaking one off.
I know an old guy who has been a mechanic for 40 years and also owns a couple of shops. I'll try and get ahold of him and see how he goes about a stuck plug.
I think Sparky has the best and safest ideas here if you don't want to take it in.
I know some Ford trucks are known for having issues when removing spark plugs. Some use a battery operated impact to loosen them up. There shouldn't be enough torque to break them off and the vibrating action helps break them loose. I'd still be careful that way though. I have a 20v Dewalt impact driver. It's small but that thing has some decent power. As you know, regardless on how you try and get a stuck one out, there's always the risk of breaking one off.
I know an old guy who has been a mechanic for 40 years and also owns a couple of shops. I'll try and get ahold of him and see how he goes about a stuck plug.
BlazingTrails
Member
- Apr 27, 2014
- 19,409
Missed this comment earlier?BlazingTrails said:
From the service manual: "Notice: Allow the engine to cool before removing the spark plugs. Attempting to remove the spark plugs from a hot engine may cause the plug threads to seize, causing damage to cylinder head threads."
I've never used antiseize on plugs and never had any issues....
Ok...you've never steered me wrong before, and it makes sense in a way...but everything I've seen out there says engine should be cold. My own (often flawed) logic reasons that it's more important to tighten things when cool (thinking of wheel lugs). Maybe the book say change plugs cold just to cover their butts .BlazingTrails said:
BlazingTrails
Member
- Apr 27, 2014
- 19,409
Let's agree to disagree. There's the manual you can read, and then there's 16 years of real world experience. Not to mention working along side several bad ass old school mechanics over the years. I've never broken a single spark plug.coolasice said:
littleblazer
Member
- Jul 6, 2014
- 9,265
My rear two were in there pretty good, I went for a drive and let it cool with the hood open for a couple hours, the head was slightly warm, probably 100 degrees. I was using a regular craftsman ratchet, after that didn't work I pulled out the spark plug ratchet, essentially it has a flex head and a longer handle. That broke it free quite quickly, they were the originals too, I knew that cause of the old part number 41-981. 
I wasn't really afraid to use force, pulling the plugs from the boat in a cast iron head that had salt water dripping on it for the last three years, that required force. Sorry to whore up your thread, moral of the story, longer handle = easier job. But I would recommend the anti-seize, even though I've personally never used it. And only re install when it is completely cooled.
Edit: I'm not saying add three feet of pipe to the end of the ratchet though, that will just end badly, but a little over a foot (head to end) should be okay. (don't need to get blamed for anything breaking, sorry)
I wasn't really afraid to use force, pulling the plugs from the boat in a cast iron head that had salt water dripping on it for the last three years, that required force. Sorry to whore up your thread, moral of the story, longer handle = easier job. But I would recommend the anti-seize, even though I've personally never used it. And only re install when it is completely cooled. Edit: I'm not saying add three feet of pipe to the end of the ratchet though, that will just end badly, but a little over a foot (head to end) should be okay. (don't need to get blamed for anything breaking, sorry)
Don't worry about blame Lol,I'm reading everything but ultimately it's my responsibility for how things go. I have spark plug sockets but I didn't know there was a specific spark plug ratchet. Thanks.
[quote name="littleblazer" post="383712" timestamp="1420403346
Edit: I'm not saying add three feet of pipe to the end of the ratchet though, that will just end badly, but a little over a foot (head to end) should be okay. (don't need to get blamed for anything breaking, sorry)[/quote]
[quote name="littleblazer" post="383712" timestamp="1420403346
Edit: I'm not saying add three feet of pipe to the end of the ratchet though, that will just end badly, but a little over a foot (head to end) should be okay. (don't need to get blamed for anything breaking, sorry)[/quote]
littleblazer
Member
- Jul 6, 2014
- 9,265
It's just a fancy tool, not necessary, it's just a longer 3/8 ratchet that the head flexes and the handle is slightly bent so that when you yank it it keeps everything in line. Just adding a little length to a regular ratchet will accomplish the same thing.sunliner said:
marinegrunt
Member
- Oct 13, 2012
- 110
Yeah, it might be the same reason why "caution hot" is on the side of a McDonald's coffee cup.
The logic behind the warning does make sense but you sometimes run into a lose lose situation. You keep torqueing and the plug breaks or you take a chance that the threads won't strip out. I've had a couple plugs break but I've never stripped the threads on a hot engine. It's definitely a possibility if the warning is there though.
I talked to that old mechanic and he said if he gets one that won't come out he lets the engine come up to temp. He said he has pulled the threads but hasn't had one break in 20 years. To get the metal shavings out he sticks a small blow gun inside and there's only one way out. They make special helicoils for spark plugs.
With the plugs being easy to get to it wouldn't be all that tough if you do end up pulling the threads. They also have Time-serts instead of helicoils. It's the same idea though. I want to say a helicoil spark plug kit is about $30 or so but can't remember for sure. It really wouldn't take that long but let's hope you don't have to go that route.
The logic behind the warning does make sense but you sometimes run into a lose lose situation. You keep torqueing and the plug breaks or you take a chance that the threads won't strip out. I've had a couple plugs break but I've never stripped the threads on a hot engine. It's definitely a possibility if the warning is there though.
I talked to that old mechanic and he said if he gets one that won't come out he lets the engine come up to temp. He said he has pulled the threads but hasn't had one break in 20 years. To get the metal shavings out he sticks a small blow gun inside and there's only one way out. They make special helicoils for spark plugs.
With the plugs being easy to get to it wouldn't be all that tough if you do end up pulling the threads. They also have Time-serts instead of helicoils. It's the same idea though. I want to say a helicoil spark plug kit is about $30 or so but can't remember for sure. It really wouldn't take that long but let's hope you don't have to go that route.
littleblazer
Member
- Jul 6, 2014
- 9,265
This is what I was pulling on, the amount of torque is significantly greater than what can be achieved on a shorter ratchet, so a regular sized one has less of a chance of breaking a plug than this one does. 
Edit: Plugs are pretty hard to break when you are using a spark plug socket, but its not impossible, like everyone else said, keep it strait.
Edit: Plugs are pretty hard to break when you are using a spark plug socket, but its not impossible, like everyone else said, keep it strait.
marinegrunt
Member
- Oct 13, 2012
- 110
That's a nice ratchet. It looks like it would come in handy for a lot of other things besides spark plugs. I too didn't know they had a ratchet specifically for spark plugs. I can see how it could help keep more of the force where it needs to be.
littleblazer
Member
- Jul 6, 2014
- 9,265
Tight spaces and it folds 90 degrees and it can be used like a screw driver. It's quite useful and it's older then me. (At least 20) it's a dual pawl and I believe it's 82 teeth, so in tight spaces you get a few clicks instead of just one or two. And the bend in the handle makes it nice to hold/work with.marinegrunt said: