spark plug removal - best practice?

JC1

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4,499
Location
Oshawa, Ontario Canada
Originally Posted by Schmoe
NEVER remove plugs when the engine is even warm. You want ambient temperatures. My experience is not getting them loose, it's actually making sure the plug socket fits securely on the plug before you even begin to loosen. If not, you can round off the plug edges and then you got problems. I always drop the socket with an extension on to the plug and make sure it's on there nice and tight, then hook up ratchet and slowly remove them.
+1. If you can't feel slight tension when you are loosening the first plug then I would stop. Don't try to be an Ape man when removing plugs. Slow constant force works for me. Post pics of these plugs when you get them out. I'm curious to see their condition.
 
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4,165
Location
WA
Originally Posted by NissanMaxima
And, do folks think cranking the engine after they are all removed to blow out penetrating oil (as NGK suggested) is unnecessary?
Not unless you plan to use enough penetrating oil that it would fill up the combustion chamber once the plug is removed. (you could hydrolock the engine like I mentioned)
 
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1,526
Location
TX, USA
Try it first before expecting the worst. Who knows, there may NOT be any problem or challenge.
 
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14,539
Location
Santa Barbara, CA
I was always taught to always do it on a cold engine, especially with aluminum heads. That being said the current best practice is to do it on a warm engine. Then you have oddballs like the Ford 3V engines with the 2 piece plugs where people have found the best way to remove them is on a hot engine with a 3/8" impact gun ignoring the TSB to let them sit overnight with carb cleaner in the holes.
 
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927
Location
ottawa
How are you supposed to compression test an alum engine then???????????????? If you can not get it to operating temp before plug removal?
 

Kestas

Staff member
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13,729
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The Motor City
I could never understand why it was instructed that spark plug removal be done on a cold engine... why? What's wrong with doing it on a hot engine? If anything, a hot engine would expand the aluminum hole more than the spark plug, making for easier removal.
 
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933
Location
Arizona
The reason you change plugs on a cold engine is not for removal but for reinstall. Hot aluminum and cold plug fits loose ...much easier to strip threads. Most issues Ive ever seen/heard of are from water getting into that area and sitting. Aluminum oxide (Rust) is very hard and will tear out the threads before letting go. Old fords had drain holes that would clog and hold water. So IMO the chronic hand washing ADD types that must wash their engines too its gonna be more likely an issue. If you use penetrating oil at all make sure the boots don't get contaminated. They can easily short out and cause rough idle or worse. Use plenty of Dielectric grease on them.
 
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137
Location
TX
I just remove 'em with the engine cold. Try to keep pressure straight down on the plug and not on the ratchet handle. Back and forth if it's a bit stubborn, but don't muscle it. Penetrating fluid would be OK if it doesn't want to come out, but I've never had to go that route.
 

wtd

Messages
2,457
Location
southwest Mo.
Originally Posted by bdcardinal
I was always taught to always do it on a cold engine, especially with aluminum heads. That being said the current best practice is to do it on a warm engine. Then you have oddballs like the Ford 3V engines with the 2 piece plugs where people have found the best way to remove them is on a hot engine with a 3/8" impact gun ignoring the TSB to let them sit overnight with carb cleaner in the holes.
I was also taught to do it on a cold engine when the vehicle had aluminum heads. Kind of off topic but does Ford have a better replacement Motorcraft plug for the 2 piece ones? My fiancee has a 2007 Mustang GT with the 2 piece plugs. I was thinking of changing them out early if there was a better plug out there. Thanks.
 
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6,688
Location
California
Originally Posted by bdcardinal
Then you have oddballs like the Ford 3V engines with the 2 piece plugs where people have found the best way to remove them is on a hot engine with a 3/8" impact gun ignoring the TSB to let them sit overnight with carb cleaner in the holes.
Reminds me of a time when I saw the techs use a 3/8" electric impact to R&R spark plugs. This was done on Hondas. I was taught via the Haynes manuals to always remove spark plugs cold. I also applied a little anti-seize to the threads and a little silicone grease to the wire boot or COP coil end.
 
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3,922
Location
SW Ohio
Originally Posted by NissanMaxima
But what about that video from Motor Week and Pat Goss (linked in my first post) saying you should start backing them out and then start the engine to presumably blow out any loosened carbon that would otherwise pull up into the threads when you continue to remove the plug?
That sounds like one of those "tricks" that some mechanic stumbled upon once or someone told him about it and he's dead-set that it works, he's done it for 37 years with no problems, and everyone else should do it too.
 
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14,539
Location
Santa Barbara, CA
Originally Posted by wtd
Originally Posted by bdcardinal
I was always taught to always do it on a cold engine, especially with aluminum heads. That being said the current best practice is to do it on a warm engine. Then you have oddballs like the Ford 3V engines with the 2 piece plugs where people have found the best way to remove them is on a hot engine with a 3/8" impact gun ignoring the TSB to let them sit overnight with carb cleaner in the holes.
I was also taught to do it on a cold engine when the vehicle had aluminum heads. Kind of off topic but does Ford have a better replacement Motorcraft plug for the 2 piece ones? My fiancee has a 2007 Mustang GT with the 2 piece plugs. I was thinking of changing them out early if there was a better plug out there. Thanks.
SP-547 is the latest number, with SP-514 and SP-462 being the previous numbers. I think they are still technically 2 piece but the Mustangs tend to have a lot less plug break issues than the trucks. Probably because Mustang owners tend to be a bit more proactive with changing the plugs.
 
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14,539
Location
Santa Barbara, CA
Originally Posted by nthach
Originally Posted by bdcardinal
Then you have oddballs like the Ford 3V engines with the 2 piece plugs where people have found the best way to remove them is on a hot engine with a 3/8" impact gun ignoring the TSB to let them sit overnight with carb cleaner in the holes.
Reminds me of a time when I saw the techs use a 3/8" electric impact to R&R spark plugs. This was done on Hondas. I was taught via the Haynes manuals to always remove spark plugs cold. I also applied a little anti-seize to the threads and a little silicone grease to the wire boot or COP coil end.
The theory on the 3V motors is the impacting breaks up the carbon. You can also bring the car in before the shop closed, crack the plugs loose, and put carb cleaner in the holes and let it sit overnight. Then they should come out by hand or with a 3/8" impact no issues. Then obviously put anti-seize on the interference fit portion and reinstall by hand.
 

wtd

Messages
2,457
Location
southwest Mo.
Originally Posted by bdcardinal
Originally Posted by wtd
Originally Posted by bdcardinal
I was always taught to always do it on a cold engine, especially with aluminum heads. That being said the current best practice is to do it on a warm engine. Then you have oddballs like the Ford 3V engines with the 2 piece plugs where people have found the best way to remove them is on a hot engine with a 3/8" impact gun ignoring the TSB to let them sit overnight with carb cleaner in the holes.
I was also taught to do it on a cold engine when the vehicle had aluminum heads. Kind of off topic but does Ford have a better replacement Motorcraft plug for the 2 piece ones? My fiancee has a 2007 Mustang GT with the 2 piece plugs. I was thinking of changing them out early if there was a better plug out there. Thanks.
SP-547 is the latest number, with SP-514 and SP-462 being the previous numbers. I think they are still technically 2 piece but the Mustangs tend to have a lot less plug break issues than the trucks. Probably because Mustang owners tend to be a bit more proactive with changing the plugs.
Thanks for that info. Her car only has 24,000 miles so I doubt it would be an issue yet. I didn't know if Motorcraft had ever come out with a 1 piece replacement. I know a couple of other companies have but I like using OEM brand plugs if possible.
 
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279
Location
Kah-nah-dah
Ugh... doing the plugs when an aluminium head is hot, is just begging to rip the threads out. Blow em out. Remove when the engine is ambient temp, install when the engine is cool. Use a touch of nickel anti-seize on the threads. Torque to 15ft lbs. If they are gasket type, if they are wedge style, +1/8 turn once tight. It's how I do everything from flat heads to VVT DOHC engines, 2 and 4 strokes. Personal, relatives, friends, work, and customer's vehicles. I've never had to repair threads in a head that I did plugs on, I've had to repair others who've stripped or blown them out.
 
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325
Location
Colorado
Thread starter
Hi all: Well bolstered and encouraged by the support and education of my BITOG brothers I removed the spark plugs today. I have never done a spark plug job on a car with coil packs so it was as an interesting experience. I was meticulous about cleaning all sand and dirt away from the coil packs before removing them. I had to zip tie connectors and other peripherals out of the way so would have an unencumbered access to the plugs. Coil packs came right off. To my pleasant surprise, there was zero dirt/sand actually down in the spark plug holes but I gave each a good blast of compressed air by taping three of those straws together so it would reach way down into the hole. For the first three, I cracked them loose about 1/4-1/2 turn. Here I appreciated the tip about attaching the spark plug socket first to get it well-seated and THEN attaching to the ratchet. I probably would have done this anyway, but thanks for that tip. It definitely took a considerable but not too excessive amount of tug on my 3/8" ratchet and certainly more than 18 or so ft lbs speced to tighten them and I was pretty nervous about having to apply that much tug on the ratchet but it slowly gave way as I carefully bore down on the shaft on the extension. However, it probably felt like more torque due to the short length of the 3/8" drive ratchet. I don't know. I did not put any penetrating oil before starting as it seemed folks here thought it wouldn't make it past the tight gasket and I suspect they are right. After loosening the first three 1/4" or so turn, I drizzled down a few drops of PB Blaster letting it run down a long screwdriver right to base of the gasket. I let it set a few hours. In the meantime, I tackled the rear three which were somewhat more challenging to get to simply reach-wise but not terribly difficult. I found that after getting those loose by about 1/4-1/2 turn, they spun out relatively easily so didn't mess with the oil. I wrapped up the afternoon by wrapping a paper towel around a screwdriver, dipping it in isopropyl alcohol and then inserting it down into the spark plug hole to carefully clean any residual penetrating oil and debris from where the new plugs will contact the top of the cylinder. A few questions now: 1. My only regret is on the first one after breaking it free by about 1/8" of a turn, it seemed so hard to turn that I thought perhaps retightening it to just short of the original location might help break free crud in the threads. I did not apply oil before retightening. I didn't do that with the others and just maintained steady CCW motion, in between repositioning the ratchet handle for another short swing. Should I be OK with that first one? 2. I tried in vain to get a good look at the threads. They are so deep it was really impossible to get a good side-on view of them. I have a very tiny inspection mirror I was able to insert down the spark plug hole shaft hovering over the threads. They seem OK as much as I can see. 3. No need to do any thread chasing right? Would it be a good idea to run each new plug into finger tight point and then pull them out again to sort of clean out any crud in the threads? I would wipe out the treads of the spark plugs of any debris collected. 4. NGK states that with anti-seize to reduce torque by 20%. I got to thinking that having used a few drops of penetrating oil in the first three which now is certainly on the threads, does this now act like anti-seize such that I should drop the torque down by 20%. My manual says 14-22 ft lbs and I was going to torque to 18 ft lbs figuring mid point was good. That is still almost 20% lower than top torque so I'm guessing I will still be good at 18 ft lbs. I plan on inserting the new NGK plugs (same ones that came out) dry per NGK instructions. I could detect no trace of antiseize on the threads although maybe a small amount would be undetectable anyway. For sure, I will never wait this long again to do this job although in all honest with about 76k miles on the car and about 3-4k miles a year, not sure I'll even be around when it comes due for the next change assuming the car is still running then anyway - but it is in spectacular shape so who knows! 5. the top of the pistons were pure black (if that is what I was looking at). I didn't really know what to expect here other than I know folks like to look at them when they remove plugs and even insert borescopes down for a better look. Attached for your viewing pleasure that only a member of this forum could appreciate are some nice zoomed in photos of one representative plug from various angles and a new identical one. I was really interested to measure the gap thinking it was perhaps at least 0.005" larger than spec but to my surprise they were at most about 0.002 off the high end spec! I was hoping that the gap had really increased and that new plugs with the resotred gap would provide more hp now but perhaps gap change alone is not a reason to change plugs as I have read on this forum resistance changes too so we will see. I read on the NGK site that new spark plugs really don't increase/restore hp but rather fuel efficiency. I have read on this forum some folks experience a real or perhaps perceived hp/performance change. The tip was definitely not sharp like the new one although who knows if the NGK design has changed since 1995. The electrodes look tan like I read is a good sign. [Linked Image] [Linked Image] [Linked Image] [Linked Image]
 
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4,165
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WA
Looks pretty much like normal wear to me. No deformation of center electrode or ground, no signs of wetting (fuel/oil), no excessive carbon/ash deposits. A little bit of burning on the ceramic but nothing I'd personally get worked up about, especially if the plugs have been in service a while.
 
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7,759
Location
Oklahoma
Surprised how big of a gap on picture number 2 only after 24K miles. Color wise, engine is working fine. You should take a look at removing spark plugs from a 5.4L 01 F150 plugs....UGGGHHHHHH.
 
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