replace your spark plugs
 

I just replaced the spark plugs this weekend. I thought it would be more difficult than it was. For anyone who changes their own oil, changing your spark plugs is not a bad do-it-yourself task.

Tools: 5mm hex socket (or allen wrench), 8 inch socket extension, 10mm socket, spark plug socket.

Here is what I did:

1) remove the rear wheels
2) remove the wheel well cover (use a 10mm socket on the 2 nuts). I found it easier to reach the plug closest to the front of the car with the cover removed.
3) there are 3 plugs on each side of the engine. you can see the 3 coil packs with the rear wheels off of the car. remove the wire clip from the coil packs by pinching (with your fingers) the clip about an inch from where it attaches to the coil pack. there are 2 5mm hex screws that hold the coil pack to the engine. remove the 2 scews and pull the coil packs from the plug.
4) put the 8 inch extension and plug socket into the plug hole and fit it onto the spark plug. fit the socket wrench to the extension. (i found it easier to keep the socket wrench off of the extension and socket until i had them placed on the plugs). remove the spark plug.
5) put in the new plug in, attach the coil pack (be careful to keep the coil pack wire away from the coil pack itself when you are screwing it back on. (i managed to pinch one of my coil wires behind the coil pack when i was screwing it back on).
6) replace the wheel well cover

I also had to remove a clip (I think i was to an O2 sensor) in order to get to the 5mm hex screws for the plug closest to the front of the car.

All in all it took me a couple of hours to replace the 6 plugs, but I'm also not a mechanic by any means.

I used the original Beru plugs for the replacements.

Porschegeorg, good job...but why did you replace them so soon?

You might add:

Put a little anti-seize on the new plug's threads to keep them from getting stuck.


Doesn't sound very complicated, maybe a couple hours worth of work? Might pull mine just to see what they look like - make sure it's not running poorly since I got that P1129 code a couple weeks ago. I also need to remove and clean the MAF soon, too.

Bill....I know I only have 4900mi on the car, but I couldnt stand the idea of having the same plugs in my car for more than 3 years. I get neurotic about stuff like that :)

How many times did you wash your hands when completed? :D

Did you use torque wrench? If so, did you adjust torque with the anti-seize compound? Thanks!

it shouldnt take 'coule hours', maybe like an hour or so.
i will be chaning out my plugs as well as the serpentine belt. i will document it w pictures and use your guide as well so soemone who hasnt done it can see the actuall process.

thx for the writeup btw

If you jack up one side of the car at a time you don't need to remove the wheel well cover.

Hi,

You can change the plugs in as little as 20 min. You should use a torque wrench to insure that the plugs are properly sealed and indexed. Also, Anti-Sieze is unecessary and you run the risk of overtorqueing the plugs and stripping the Head (aluminum).

As mentioned, lift one side, slide underneath (I use a creeper). Loosen and the Coilpak screws at one time, pull the Coilpaks after marking them w/ paint pen or tape to avoid mixing them up. Pull all 3 Coilpaks (pull and slight twist). Untorque all 3 plugs with ratchet handle - not torque wrench. Hand loosen all 3 plugs and remove marking them (Cylinder #) for later inspection.

Check Gap on all new PLugs and adjust as necessary - they come pre-gapped but are notorious for being off which will affect a smooth idle. Check Spark Plug Tubes w/ finger to insure no Oil leaks. Insert and hand tighten all 3 plugs. Torque plugs to spec in 2 stages.

Insert Coilpaks on plugs, following the labels. Insert Coilpak screws on all Coilpaks - hand tighten. Torque Coilpak screws in 2 stages. Go to other side - repeat. Hope this helps...

Happy Motoring!... Jim'99

I didnt use anti-seize and I didnt use a torque wrench. Call me crazy, but I've changed a bazillion plugs in my life on a bazillion different makes/models, and never torqued a-one. Never had problems either.

But now (thanks to you Jim), I'll be worrying about this until I change the plugs again! :)

Bill- only washed my hands 1 time per plug. ;)

I would never skip anti-seize on an aluminum head car. Steel threads into an aluminum head? I would not risk it. To each their own.

When using anti-seize, reduce the tightening torque by 30-40% and you won't have any concerns about thread stripping.

what are the torque specs?

Hi,

A couple issues. Plugs s/b changed out every 2 yrs. regardless of the Manufacturers claims. This is for 2 reasons: First, you actually get the chance to inspect them and insure that the electrode hasn't broken or such. Second, you'll never have the plug seize. Plugs are cheap (possibly the cheapest thing you can do to a Porsche), it's a false economy to let them run forever.

Using an Anti-seize can actually impede the grounding of the plug as it insulates the metal-to-metal contact. Most Anti-seize compounds will actually glue the plug in place as the 'grease' cooks off from repeated heat cycles. That is, unless you use a Hi-temp Anti-seize which actually uses a metal (usually Copper) to withstand the heat. But, now you have the interaction of multiple metals going on.

Also, 50% of the torque spec is to overcome the friction between the threads. All torque specs (unless otherwise stated) assume a dry thread. If using an Anti-seize, you need to reduce the Torque spec by 50%, not 30-40%.

If you properly torque the Plugs - Dry, change every 2 years, you'll never risk stripping the threads or having them seize. BTW, the Torque Spec for Dry Threads is 30+3 Nm or 22+2 Ft. Lbs. and should be set in two stages.

Hope this helps...

Happy Motoring!... Jim'99

Jim,

What does it mean to torque the 22+2 in two stages? Would I torque it to 22 and
then 24ft/lbs?

Georg


btw.....I do torque my lugs, but I do not own a smaller torque wrench for things like plugs and such. Any recommendations??? Craftsman????

I think Jim means 22 plus or minus 2???

Torque in two stages means torque once at say 1/2 the final amount all 3 plugs on that side, and then go back and do the final torque setting at 22.

Porschegeorg, are you going to be able to sleep tonight...thinking about your spark plugs! :)

Hi,

No, the torque spec is 22 + 2 Ft. Lbs. First torque to 22 and then 24, that's straight from the Service Notes...

Happy Motoring!... Jim'99

I have my eye on a $229 Snap-on torque wrench. Perhaps if I purchase it, I'll be able to sleep better (on the couch, however).

Hi,

Snap On is good stuff, but if you go with a top-end Craftsman, you get free recalibration (not certain Snap On offers this). That can be important because a recent SAE study of 1000 random quick release (Click Type) Torque Wrenches showed them to be as much as 50% inaccurate. So instead of applying 24 Ft. Lbs., you could be applying as little as 12 or as much as 48 ft.lbs.

The most accurate, and those used by professional engine builders, are the Beam Type. I have both and can check my quick release against the Beam Type for a fair accuracy check...

Happy Motoring!... Jim'99

Well, this isn't the first time and it won't be the last, but I disagree.

Yes, you must use a high-temp anti-seize. And no, it will not "glue" the plug into the chamber. The correct anti-seize for a steel plug into an aluminum head is a copper-based high temperature anti-seize. Agreed with your comment about checking the plugs every couple of years, but I'm not sure what that comment was in reference to.

Yes, I have seen steel plugs seize into aluminum heads, and no, they weren't overtorqued or left for an unreasonably long time. The electrolysis between the two metals is what you're trying to eliminate by introducing the third metal (copper). Having to helicoil an expensive head is not something I'm willing to do AGAIN because someone forgot to use the anti-seize.

As I said though - to each his own.

If I had a lot of money to buy a torque wrench, id get a digital one. My brother made a couple in college and they are super accurate. I think they may sell kits so you can make your own, but im not sure.

Well.. yes and no. The quality digital wrenches are great, but they need to be calibrated periodically (just like a click type wrench). I agree with Jim that the beam type, though not necessarily the most convenient, are the most repeatable and trustworthy. I will never get rid of my beam type, and use it almost exclusively for critial applications like steel bolts into aluminum threads.

JV

My short response is that all of this has been covered on Renntech. I have the 986 and 996 shop manuals. There are errors in both manuals.

You do not torque a spark plug to 22 lbs. then go back and torque it another 2 lbs. You do not torque it 24 lbs in one shot This is an error in the Boxster shop manual when it says 22 plus 2. A smiple printing/translation error. This error is not in the 996 manual. It is 22 plus or minus 2.

Another example is the size of the wrench to remove the belt. It is 24 mm on the 986 and 996. I have changed the belt on both. The Boxster shop manual says 24 mm, but the 996 manuals says 27 mm. A mistake in the 996 manual.

Porsche issue a TSB in 1994 that says not to use anti-seize. A copy of this bulletin is on Renntech. The 986/996 did not exist in 1994. But until Porsche issues another bulletin on anti-seize the mechanics are taught to follow the old.

Porsche needs to outsource its publications like other car companies. They cannot not even spell Boxster correctly on the 2001 tech intro booklet.

All of this is from my memory, so don't quote me.

that's why I never read the manual, throw out all instuctions for video equipment, end up with 20 extra screws and washers from Ikea, Can never find the English section in user manuals and post all questions on internet forums...
scribners error...what's next?

I tend to agree with MNBoxster and Tool Pants on not using antisieze.

I sell Loctite brand as one of the industrial lines I represent for work and will ask the mfr. rep. for some "official" input on this and post it later.

Most of the issues with using it have been addressed already such as lubrication/torquing/stripping threads, etc.

See ya,

Jeff

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.

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

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

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

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.

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....

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

I started using it in the late 60's when first building motorcycle engines. Always used a high temp lead or copper based paste. I also use it on my wheels. It's saved having the wheels bond to the hubs (alum alloy to steel). Never had a problem with it. Yes, a little goes a long way. I was taught to spread it evenly in the threads and wipe excess prior to threading.

We use it in the refinery business as a matter of course. You try removing a 2 1/8" nut that's been heat cycled to over 800F several hundred times without it....it's no different in cryogenic service. Lots of our refrigerated propane systems run at -60F and anti seize is a must.

I've read the TSB's also and take them with a grain of salt.

To each his own indeed!