Planet 9

I don't see anything mentioned by Porsche on this or find anything in the numerous exhaust install articles. All I found was that Porsche recommends replacing them each time. Good practice in any case.

Should an anti-seize compound be used on the exhaust manifold bolts when replacing the headers? Is there any particular type preferred, nickel, copper, moly? And if anti-seize is used should the torque value be reduced?

Maybe not an issue for P-cars but I've always found that these pesky things want to rust, freeze up and snap off on other cars.

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Les

I'm not sure how antiseeze would stand up to that heat. I hope someone will chime in with some good data on this because I've thought of doing the same, because I like to rotate my exhaust systems regularly...

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Gator Bite
PCA Cayman Register Advocate

I used anti-seize for the bolts between the exhaust manifold and the pipe that goes back to the silencer. There is no need for anti-seize for the bolts that attach the exhaust manifold to the heads. The heads are aluminum, and the bolts therefore cannot rust themselves to the head as could occur with the usual iron block.

Isn't there a special kind of anti-seize that is made to withstand heat? It's made for exhaust and brake parts.

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’08 Cayman S, 6 Speed, PASM, Sport Chrono, Sport Seats & Steering Wheel, 19” Carrera Sport Wheels, PCM, Bose, Xenon, plus some other stuff not worth mentioning

Yes there are several, here is an example:

Molykote P37

More P37 Info here

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Current Cars:
2008 Orange - Limited Edition Boxster S
2004 Atlas Grey - Boxster S

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Have to disagree with you there i'm afraid Fort.

We would suggest using anti-seize (we use copper slip as our preffered topping) on all bolts as a matter of principle.

Haven't seen any issues on Caymans yet, mainly because we havent seen any with that high a mileage yet. But on 986 Boxsters and 996's we get rusted up exhaust to head studs/bolts ALL THE TIME, which then shear off. These engines still have aluminium blocks and heads and were only talking cars that are a couple of years older than the oldest Caymans and only a few extra thousand miles on the clock.

A good days work if the engine stays in the car to drill out each individual stud/bolt by hand and rework each one, tapping holes etc.

The fact is, for a few extra seconds with some paste you could end up saving yourself a lot of Dollar.

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[SIGPIC][/SIGPIC]

I'd have to agree. I've had similar experiences on aluminum motorcycle engines. The aluminum oxidizes and the threads turn to a white dust.

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Gator Bite
PCA Cayman Register Advocate

OK - thanks for the correction!

Thanks for the input. A material and process guy whose an aquaintance also got back with me today. He indicated for steel bolts in aluminum either the copper based type products already mentioned or a molybdenum sulfide type anti-seize would be good. Since this is in aluminum the temperatures won't be high enough to do more than cooked off the oil used as a carrier for the friction modifiers.

From the sounds of it no one reduces the torque for lubricated threads. Given the low torque called for it probably doesn't make a significant difference.

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Les

For GB who likes to rotate exhausts having the bolts corrode likely won't be the problem. Wearing out the threads in the heads maybe. Little anti-seize might help there too.

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Les