replace your spark plugs

[Tool Pants]

But I do use anti-seize on my vehicles for the spark plugs, including my Boxster. When we have a work on cars day and replace the plugs I do not use it unless the owner says ok. Not my car so I follow what the owner wants.

I have the gray and copper colored stuff, for picky people like me.

Just did it on my 1988 Toyota pickup that I have owned for 18 years.

I am old, and old habits die young.

[jwilson95]

All-

My Loctite rep. basically contradicted himself. I guess they want to sell product to those willing to use it. They have a product specifically for spark plugs, but then they have a I guess it is personal opinion/choice:



Model # : LOC37617
Item Id: 372112
Loctite 20 Gm Silver Anti-Seize Stick: Loctite Silver Anti-Seize Stick is a heavy-duty, temperature-resistant, petroleum-based lubricant compound fortified with graphite and metallic flake. Will not evaporate or harden in extreme cold or heat. Use during assembly to prevent seizing, galling and corrosion. For use in assemblies up to 1600 F (871 C). Test to Mil-PRF-907E. Suggested Applications: For easy removal of spark plugs, cylinder head and exhaust head bolts.


There is a second school of thought on using anti-seize on spark plugs; the AC/Delco spark plug installation procedure page says not to do it:
Do not use any type of anti-seize compound on spark plug threads. Doing this will decrease the amount of friction between the threads. The result of the lowered friction is that when the spark plug is torqued to the proper specification, the spark plug is turned too far into the cylinder head. This increases the likelihood of pulling or stripping the threads in the cylinder head. Over-tightening of a spark plug can cause stretching of the spark plug shell and could allow blowby to pass through the gasket seal between the shell and insulator. Over-tightening also results in extremely difficult removal.


He did say that if you use it, use it very carefully because a little goes a very long way and will get down in the chamber if it is excessive.

Let the battle rage on!


Jeff

[John V]

You don't need much. A small dab near the end of the plug will work its way up the threads as you screw in the plug.

If you tighten the plugs using the "hand tighten until seated, then one additional 1/4 turn" you'll never overtorque them.

I guess I am paranoid after seeing the results of aluminum to steel galling. Never again. I use anti-seize on my wheel lug bolts too. I remove and install wheels two to three weekends a month for the spring and summer, and being 1,000 miles away from home with a stripped stud is no fun. Been there, done that at the Peru National Tour two years ago and it sucked.

John V

[MNBoxster]

Hi,

Sorry John, to each his own...

Hand tightening and then going another quarter turn is widely imprecise for a procedure where precision is exactly what is called for to insure proper sealing, and indexing, of the plug. I wouldn't be surprised to see variations of as much as 15 ft.lbs. over 6 plugs using this method. They may never be overtorqued as you say, but they never be properly torqued either.

I do admit to having used this method in my distant past when working on motors with Cast Iron Heads (Flathead 8's, Smallblocks, and the like), but when working with Aluminum Heads (actually usually Aluminum/Magneseum alloy), proper torqueing of the plugs is key to both preventing seizure and galling the threads, and proper sealing and indexing. I have installed/replaced literally hundreds of plugs in my life using this method without a single issue. And, Porsche does not specify using anything on the threads, if this were to cause issues, they certainly would.

Fact is, the only time I ever had a seized plug requiring a Heli-coil fix was when an Anti-Seize had been previously used, so my natural inclination is to stay away from it for Plugs. I do use Anti-seize for many other procedures on the 6 cars I own and maintain.

Again, I'm averse to using it on wheel lugs as well unless specifically called for. Proper torqueing, in stages, has never left me wanting. But, to each his own...

Happy Motoring!... Jim'99

[John V]

To each his own, agreed. However if a plug seized in "due to anti-seize being used" then someone used the wrong anti-seize. User error.

[Tool Pants]

I had a plug seized in the head. It was an aluminum head. Standard copper plug with nickle plated threads. Technically that should not have happened. Pulled the head for a heli-coil. That is when I started using the stuff on plugs. That was something like 25 plus years ago. It is an old habit I have. Guess I will not go to Porsche heaven....

[John V]

Never mind that helicoils used for spark plugs are a nightmare on their own, but not a whole lot of other options....