Why no anti-seize on spark plugs?

[Moose]

I read the how-to on spark plug replacement for my Boxster. I trust the 996 replacement is essentially the same. Two things. First, why no anti seize on the plugs? I always used anti-seize on my 928 aluminum heads. What gives?

Also, I see that the serpentine belt must be changed from inside the passenger compartment. Any way to get at the plugs from in there? Also, I think I will use plastic tarps to protect the inside of the car when changing the serp belt.

David Cmelik

01 Boxster 5sp seal gray metallic

:cheers:

[Gundo]

Not sure about the anti-seize, but I do know, the only easy way to get at the plugs is to remove both rear wheels - no way you could do it from passenger compartment....

[Loren]

Porsche does not recommend the use of anti-seize compound on spark plugs being installed in aluminum cylinder heads. The reason is that spark plug torque may not be correctly measured and the plugs will be tightened too much, damaging the threads in the cylinder head.

[Tool Pants]

This is a debated subject, like what oil or filters to use.

I started using anti-seize many years ago on every vehicle I've owned because I experienced a steel plug welded to an aluminum head on my first Fiat X/19. 3 of the 4 plugs came out fine. When I removed the 4th plug the threads came out with it and I had to pull the head for a spark plug insert. It was a Champion plug with nickel plated threads. The Fiat is a mid-engine, but it is harder to replace the plugs on that car than a Boxster.

When I replaced the plugs on my Boxster I used anti-seize. When I have replaced the plugs on local Boxsters I don't. My dealer does not.

Porsche issued a bulletin on June 14, 1991 that states not to use a lubricant on spark plugs. Anti-seize is a lubricant. What does this 1991 bulletin have to do with a Boxster/996 that did not come out until years later? Well, until Porsche comes out with another bulletin you follow the old bulletin.

If you go on the Bosch site it says anti-seize is not needed because their plugs have nickel plated threads.

Replacing the plugs on a Boxster is much easier than a 996, as the Boxster does not have the exhaust manifold and heat shield in the way. We remove the tire and the plastic shield in the wheel well to get to all the plugs.

To replace the belt on a Boxster you just slide the seats forward and remove the service cover. Porsche says to replace it at 60k miles. I have replaced the belt on four 60k cars and there was nothing wrong with the old belt, but we did it anyway since the owner had already purchased a new belt. http://www.renntech.org/forums/index.php?s...t=0entry10610

1991 Bulletin

[Moose]

Thank you for responding to my post. I appreciate it greatly.

:cheers:

[aak5454]

I think there are two issues at hand here: one technical and one customer service related.

You have two dis-similar metals in contact which present an opportunity for reaction (given the right conditions). Al and Ni do react to form some very strong intermetallic compounds, but if my memory serves me correctly ( I have a grad engr. degree in materials science), this only happens at temperature well above operating temperature of an engine. HOWEVER, the present of a third substance can cataylize such a reaction at a lower temperature; here in lies the issue the customer service issue. If you allow an anti-seize compound, you have to specify exactly how much, what types, etc, etc.(and customers will invarible take this as a license to do whatever they want) and when there is a warrenty claim it become unpleasant since the customer will never admit they did not follow the specification (or think they have, but did not) and Porsche ends up eating warrenty claims and/or pissing the customer off (bad either way). Disallowing anti-seize compound makes it simple from both a technical and customer service standpoint.

Mike

P.S. I managed an applications engineering department for a German equipment company for 4 years; I've been through many, many warrenty claims on equipment supposedly "fixed" without the aid of the manufacturer. The story is almost allows the same.....