What is the general opinion on installing spark plugs into aluminum heads? Should there be a thin coating of anti-seize lubricant?

 

That's actually a very polarizing question. AFAIK new style plugs with nickel coated threads don't need anti sieze. The manufacture may specify on their website.

The poeple that say never use anti seize on spark plugs usually say it can cause over torquing of the plugs, or that it makes the plugs contain too much heat, or that it affects the electrical connection between the plug body and the threads.

With that said, I always apply a VERY sparing amount with a q-tip, then use a torque wrench. I feel most of the problems associated with seized spark plugs are to to people over tightening.

 

From an engineering perspective, that anti-seize will change the friction, and could lead to over-tightening. I'm not an automotive engineer, so I can't say how much this matters, but given the troubles some people have had with spark plugs on various engines, I would be pretty careful.

In industrial applications, i've seem anti-seize compounds reduce friction by up to 40%, which is pretty huge.

 

I use anti-sieze and then tighten the plugs down by hand, I have never used a torque wrench. Some cars I have you are lucky to get any tool on the plug let alone a torque wrench. I have been wrenching long enough to know what tight is, calibrated wrist
I cringe every time I have to pull a plug from an aluminum head that I did not install.

 

There's a thread on the Garage Journal by a guy who had one plug (of 4) stick so hard in a Toyota's head that the spark plug's shell broke clean off. Anti-seize CAN'T be worse than that!

PS it was a nickel-whatever plug....a Denso I believe

 

On my 98 with the 5.4 I use a very thin smear of the copper anti seize. Then torque to 14 lbs. Putting the t/w on to remove them takes about 17 lbs. In any event be careful tightening them. When your wrist clicks, stop there.

 

I could post a long and in depth post about the use of antiseize on plugs .
I tire of banging my head on that wall .
I do Not recommend the use , as do many publications , spark plug manufacturers , and automotive and motorcycle manufacturers .
The problems are too many to list in this limited forum .
Torque alteration , flash over , heat dissipation , conductivity .......
Not recommended .

 

My Offy heads are vintage. I had a couple of worn out plug holes so I had steel threads installed in all eight. Problem solved.

 

Of course, those folks don't have to deal with the stuck plugs, either.

 

I have seen More issues due to improper use of antiseize and improper procedures over 30 years than seized plugs . I can count on one hand the number of seized plugs ( 3 valve 5.4 not included in that ) that were an unexplained issue . All others were caused by poor maintenance practice , washing engines causing rust or seizing issues, improper install ,or total lack of care for the vehicle .
If properly installed , properly maintained , Not an issue .

 

aluminum heads almost always use a gasketed plug... use a tiny dab of antiseize and tighten 1/2 turn past contact with the gasket. done and done.

 

Just did the plugs on my daughters v6 Escape on Sunday. 130,000 on original plugs. Must admit I was concerned, but they came out no problem. I use anti seize on most fasteners, comes from decades as a dairy farmer. But, no anti seize on plugs.


B

 

I have never had an negative issue with anti-seize...I have however had severe issues when anti-seize was not used on threaded aluminum applications. There is no worse feeling than that of a bolt turning into aluminum just fine and then galling to a stop.

 

I have always used a bit of anti-seize on fasteners that are prone to galling (like stainless steel and steel into aluminium) then torque as required . No problems yet .

 

Amen! I slather it on and onto the shoulder of the plug too!