Spark plugs keep loosening up!

[CRUZR]

I've searched for this problem using the custom search but can't find any info here on this site regarding my problem.

I went to replace my NGK plugs two months ago on my 1.8t AWM and noticed that the plugs were only finger tight when I went to remove the old ones. I know that I torqued them down to 23 ft/lbs when I installed them. No codes were thrown and the torque wrench is only about 3 years old. It's never been abused so it should be ok.

So I replaced the old set of plugs with new NGK's (again torqued to 23 ft./lbs. and went for a test drive. Car felt awesome. Flash forward to this weekend and I noticed that there was some degradation in performance. I checked the plugs and found that they were back to being only finger tight again. Has anyone else had this problem?

Should I use Loctite or should I tighten them more than 23 ft./lbs? I'm not sure what is causing this, but I've got to get this figured out/fixed. Any ideas as to what's causing this? Any/all help would be appreciated!

Happy New Year everybody!

Jim

[Steve in Chicago]

Don't use thread locker on spark plug threads.

Is this happening with all the plugs or just the same specific ones each time?

[CRUZR]

Don't use thread locker on spark plug threads.

Is this happening with all the plugs or just the same specific ones each time?

Hi Steve,

It's all of them.

[Steve in Chicago]

I'm at a loss, but I can guess a few things.

Try a different torque wrench. (this one might be out of calibration)
If you're doing the plug changes with a hot head, try doing it with a cold head.

[hu vw]

Or threads are stripped.

[TurboJim]

I've had this happen with used spark plugs but not new ones. Are you using to much anti-seize on the threads?

[VAGguy]

At a 40k mile interval (maximum) you should not need to use any anti sieze. I have never used it on spark plugs and never had a problem removing them on either of my 1.8Ts with a combined 250K

[bvariant]

Here is a recent article arguing against anti-seize entirely on modern plugs/heads:

MOTOR Magazine Article | MOTOR Information Systems

[CRUZR]

Thanks for all the replies guys. In a way you are all making me feel better because I've been stumped by this.... other than trying a different torque wrench.

I change my plugs yearly when using copper (just 12k a year these days) and every 2 years if I'm using platinum. I've never used Loctite but was wondering if that was a solution. It seems that collectively we are are against using anti-seize compounds on our plugs.

I'm going to go borrow a torque wrench from autozone and see if their tool torques them differently/better. My dad was a Service manager for an auto dealership (GM products) for most of his career. Because he started out as a mechanic, he always had all the basic tools I would ever need. He retired (and moved a distance away) and so that's why I invested in my very own torque wrench. Perhaps the problem is the torque wrench (which I bought brand new from Sears/Craftsman) just 3 years ago. It's never been banged around or mistreated. It goes back in the blister package after each and every use.

I always change my plugs when the engine is cold. So that's not it.

No, the threads aren't stripped. My dad asked if they had ever been put in to tight thereby "stretching" the threads in the aluminum head. I've done most every tune-up except the one at 110k. The dealership changed them as a courtesy when they replaced my coil packs. I don't believe they would over-torque them.

I'll let you know how I make out, but it will take some time to know as I'll have to check them in another month or so after going to Autozone....

Just an interesting note on this... though the plugs wind up just finger tight in time, there doesn't seem to be any blow by. I would think that my plug access holes would be all carboned up, but they aren't.

Thanks again for all your thoughts. It's appreciated!

Jim

[scotts13]

Sounds like you have a head on your shoulders. Somehow, I doubt it's the torque wrench; even when using mine, it always feels like I'm leaving them too loose - in other words, the instinct is to over-tighten rather than under-tighten.

Thinking back through the mists of time, the only car I've ever had the plugs keep loosening up on was a 1971 MGB. A new head (installed for other reasons) solved that.

[CRUZR]

Here is a recent article arguing against anti-seize entirely on modern plugs/heads:

MOTOR Magazine Article | MOTOR Information Systems

This was a great read. Back in the day my dad told me that 'some' of his mechanics were using loctite on the cast iron heads. According to this article, loctite would be a no-no due to the aluminum heads. They also state that threads can be "stretched" if over-tightened. I really hope that's not the problem. I don't know what the solution would be here. I recall using heli-coils on a friends v-8 (old Chevelle) he had forgotten the lefty loosey rule and snapped the plug right off in there. Had to get it out with an ez-out and then fix the threads with a heli-coil. My dad was a real hero to my friend that day!

Again thanks for the article - I'll start reading Motor magazine on-line!

[CRUZR]

Sounds like you have a head on your shoulders. Somehow, I doubt it's the torque wrench; even when using mine, it always feels like I'm leaving them too loose - in other words, the instinct is to over-tighten rather than under-tighten.

Thinking back through the mists of time, the only car I've ever had the plugs keep loosening up on was a 1971 MGB. A new head (installed for other reasons) solved that.

__________________________________________________ ___________

What I should also do is use the torque wrench to remove them and see what the ft/lbs is. I have always felt that 23 ft./lbs was "loose". Perhaps I'm getting stronger in my old age and this is much ado about a non-problem. Still seems that they are just finger tight upon removal though. I'm going to check with another torque wrench as this is the only thing that I think is plausible. The problem did seem to start right around the time of the torque wrench purchase.

[hu vw]

What I should also do is use the torque wrench to remove them and see what the ft/lbs is.

Unless the torque wrench you use to loosen the spark plugs is designed and calibrated to loosen fastners/etc. you will not receive an accurate reading. Typically torque wrenches are calibrated to work only in one direction, tightening or loosening, not both.

Are you the original owner of the car? Has anyone else performed maintenance on this vehicle?

[CRUZR]

I am the original owner, however the dealership only changed plugs once at approximately 110k when coil pack recall took place. They said they did spark plug change as a courtesy.

Currently, when I put the plugs in (and out) it feels normal. There is no cross threading at all. Plugs have always been put in by hand until snug and then torqued using torque wrench to 23 ft/lbs. I do recall one time (a long time ago) when they were a bit tough coming out. Not crazy tough just tougher than expected

So just for arguments sake, let's say that the threads are "stretched" - what if any would be the fix?

[bvariant]

I am the original owner, however the dealership only changed plugs once at approximately 110k when coil pack recall took place. They said they did spark plug change as a courtesy.

Currently, when I put the plugs in (and out) it feels normal. There is no cross threading at all. Plugs have always been put in by hand until snug and then torqued using torque wrench to 23 ft/lbs. I do recall one time (a long time ago) when they were a bit tough coming out. Not crazy tough just tougher than expected

So just for arguments sake, let's say that the threads are "stretched" - what if any would be the fix?

One other thing you might try is cleaning off the threads in the head and the ends of the plugs with a small amount of acetone or rubbing alcohol on a rag that won't leave lint behind. If there's any excess antiseize or oil, that will remove it from the mix without hurting anything, then evaporate quickly. It may not make a lot of difference, but costs very little time or money to be sure.

Sorry, I can't help with the answer about stretched threads myself but am sure others here can comment.

[Tom Dee]

Chase thee threads with a correct size tap Sap on makes a chaser tap for each spark plug thread size I use em in machine shop

[CRUZR]

Chase thee threads with a correct size tap Sap on makes a chaser tap for each spark plug thread size I use em in machine shop

Tom - I'm liking this idea. I'm actually pretty friendly with the Snap-On rep for my area. I'll ask him to order one for me. Thx! Jim

I'll keep everyone abreast of how this works out.

[Matt98B5]

I have not done anything like this but I'd think that you'd have to be careful not to get metal shavings in the cylinders, or somehow use compressed air to get them out if anything drops in there.

[Zodicus]

I had the same problem too on #3 and 6. I figured the lazy turd of a mechanic who did the tune up before I bought it just finger tightening those because they were in hard to reach areas (under the intake duct and coolant tank) - a quick 3 minutes to loosen a few screws and move said objects out of the way solved that problem. Now that I know this can happen autonomously I'll keep a closer eye on it.

[Steve in Chicago]

...I'd think that you'd have to be careful not to get metal shavings in the cylinders, or somehow use compressed air to get them out if anything drops in there.

One method is to load the channels in the tap with thick grease. The idea behind this is the grease will capture and hold most of the metal shavings.

If you have an old alloy part you don't mind destroying, drill a hole and run the tap (with grease) through it as practice.

[Matt98B5]

One method is to load the channels in the tap with thick grease. The idea behind this is the grease will capture and hold most of the metal shavings.

If you have an old alloy part you don't mind destroying, drill a hole and run the tap (with grease) through it as practice.

That makes sense. It would have to be pretty thick grease, with not too much extra blobbed on the tap so it won't come off the end of the tap when you make it to the bottom of the hole. I guess one other option is to tape a skinny hose onto a vacuum to get anything out of the cylinder.

[CRUZR]

Sorry I'm getting back so late on this, and thanks for all the great ideas / discussion.

I got a tap from my Snap On friend and went to work chasing the threads. I greased the threads on the tap before I started (as suggested). There was minimal resistance using the tap. I did all 4 cylinders, wiping the tap clean and then re-greasing after each one. I then replaced the plugs and torqued 'em down properly, then drove around for 3 months. I then removed the plugs to see if the still felt tight. They felt somewhat "tighter" in there. So I guess - problem solved. I also didn't notice any change in performance at all.

[Tomvw]

If you want to check your torque wrench, borrow a known accurate wrench with a dial, and connect your wrench to it with a suitable socket,
apply force to see if the two match.